DESIGN, DEVELOPME'IT, MANUFACTURE

AND QUALIFICAT'QN OF WE'L' -SLUG

ALL-TANTALUM CAPACITORS

FINAL F.FPORT

Period: July 2'7, 1973 - December 15, 1976

Prepared By

Robert H. Maher - Project Engineer Tantalum Capacitors

PreDared For

GEORGE C . MARSHALL SPACE FLIGHT CENTER Marshall Space Flight Center, Alabama 35812

Contract No. NAS8 -298 19

(NAS A - C F - 1 5 n 2 1 2 ) D E S I G N , DEVELOPHENT, 877- 20 3 35 MANUFACTURE AND Q V A L I P I C A T I O N OF WET-SLUG ALL-TANTALUH CAP?CITORS F i n a l Report, 27 J u l . l a ? ? - 15 3ec. 1976 (Sprague Electric Unclas C3.1 93 p HC \r>S/MP 301 CSCL r ) q A G3/33 21748

SPRAGUE ELECTRIC COMPANY North Adams, Massachusetts 01247 January 1 5 , 1977

https://ntrs.nasa.gov/search.jsp?R=19770013391 2018-07-14T22:48:33+00:00Z

Contract No. NAS8-29819 Sprague Reference: A119-59 Pro jec t Engineer: R. H. Maher

Surmlemental ReDort to the F ina l ReDort

Attached i s Table XXXVIII f r o m the final repor t , for the 250pF - 10volt r emake group of 20 units, which has been revised to include the e lec t r ica l pa rame te r resu l t s f r o m the 10, 000 hour m a r k achieved on Apr i l 1, 1977. pa rame te r s were acceptably s table throughout the tes t .

It will be noted that all e lec t r ica l

The capacitance stability data quite conclusively proves that the extended cathode capacitance has stabil ized the total capacitor capacitance throughout the tes t . comparison of this pa rame te r between the original group and the remake group with the extended cathode capacitance which makes this fac t very apparent.

Following is a

Capacitance Stability at 10, 000 Hours of 12.5"C Life T e s t

250vF - 10Volts Standard No. Units with

Acapacitance (YO) Deviation 70 ACap > 10% 0- -- Low Avg. High -

Original Units 4 4 . 9 t 2 6 . 2 +37.9 5 .8 18/18

Remake Units t 2 . 8 1 t 4 . 08 t 4 . 9 5 0.54 0 120 (Extended Cathode

Cap)

Al l requirements of this contract a r e complete.

N

0000

000

000

m

6"

0'0 0 0

000

00

0

Ns

O

...- 000000000

rn

oo

oa

oo

o

4- N' m

' *- a" w' 2- N

OO

OO

OO

O

U

a

-73

-

T A B L E O F C O N T E N T S

SECTION 1 - ABSTRhCT

SECTION 2 - SCOPE OF WORK

SECTION 3 - DISCUSSION A. Development Phase

( 1 ) Special Tooling and Equipment (2) Procurement of Parts (3) Cathode Studies (4) Capacitor Design

B. Enginee, *ng Evaluation Phase (1) Test Specification

C. Qualification Test Phase D. MSFC Pieeting

SECTION 4 -WORK TO Bd PERFQRMED DURING THE NEXT REFORT PERIOD

SECTION 5 - EXPENDITYRES AND FORECAST

Page

1

2

13 13 14 18 23 24 24 55 83

84

85

i

L I S T O F F I G U R E S A N D T A B L E S

Figure No. Title

1 Percent Cathodic Effic-sncy V s Cathoc3 Formation Voltages F o r Various Cathode Systems

Table No.

I

II

ILI

IV

V

V I

v I1

Tit le

Cathode Liner Durability Testing (560p.F - 6V)

Tempera ture Character is t ics Per S pe ci f i c a ti on hi I t - C - 3 9 0 0 6 250pF - 10VDC Rating

T e mp e r a tu r e C h a r act e r i s ti c s P e r Specification MIL-C -39006 60pF - 50VDC Rating

Vib;ation Tes t Results P e r MIL-STD-202 60p.F - 5CVDC Ratings

T emp e r atu r e Cycling P e r f or man c e (-55°C to t125"C) 250pF - 1 0 V D C Rating

Engineering Evaluation Testing Specification MIL-C -39006B Qualification Inspection - Group I T e s t

Engineering Evaluation Tes t Specification MIL-C -39006B Qualification Inspection - Group VI Tes t s 250pF - lOV, T3 Case (26 Units)

Page

19

Page

22

26

27

28

29

3 1

32

ii

L I S T O F F I G U R E S A N D T A B L E S (CONT'D)

Table No. Title

VIII

:X

x

XI

XI1

XIII

XIV

xv

Page

Engineering Evaluation T e s t Specification MIL-C -39006B Qualification Inspection - Group V I Tes ts 18OpF - 25V, T 3 Case (26 Units) 33

Engineering Evaluation Tes ts Specification MIL-C -39006B Qualification Inspection - Group V I Tes ts 60pF - 50V, T3 Case (26 Unit:) 34

Engineering Evaluation Tes t s specification MIL-C -39006B Qualification Inspection - Group V I Tes ts 30pF - lOOV, T 3 Case (26 Units) 35

Engineering Evaluation Tes ts Specification MIL-C -39006B Qualification In'spection - Group LLI Tes t 37

Engineering Evaluation Tes t s Specification MIL-C -39006B Qualification Inspection - Group IV Tes ts 38

Engineering Evaluation Tes t s Specification MIL-C -39006B Qualification Inspection - Group V Tes ts 250pF - 1 0 V / 7 V , T3 Case ( 3 Units) 39

Engineering Evaluation Tes ts Specification MIL-C -39006B Qualification Inspection - Group V Tests 180pF - 25V!15V, T3 Case ( 3 Units) 40

Engineering E.Jaluation Tes ts Specification MIL-C -3S006B Qualification Inspection - Group V Tests 6OpF - S O V / 3 0 V , T 3 Case ( 3 Units) 41

iii

L I S T O F F I G U R E S A N D T A B L E S (CONT'D)

Ti t le Page - Table No.

XVI

XVII

xvm

XIX

xx

XXI

XXII

XXIII

XXIV

xxv

Engineering Evaluation Tes t s Specification MIL-C -39006B Qualification Inspection - Group V Tests 1OOyF - lOOV/65V, T 3 Case (3 Units) 42

Engineering Evaluation Tes t 2 Volt Reverse Bias at 85°C 7 Volt Cathode Formztion

Engineering Evaluation Tes t 2 Volt Reverse Bias a t 125°C 7 Volt Cathode Formation

Engineering Evaluation Tes t 2 Volt Reverse Bias at 25°C 3 Volt Cathode Formation

Engineering Evaluation Tes t 2 Volt Reverse Bias at 85°C 3 Volt Cathode Formation

Engineering Evaluation Tes t 2 Volt P-everse Bias at 25°C 5 Volt Cathode Formation

Engineering Evaluati?q Tes t 2 Volt Reverse Bias at 125°C 5 Volt Cathode Formation

Engineering Evaluation Tes t Test /Sample Plan (UnitsITest)

Ripple Current Tes t on Remake C'niys 60pF - 50V, ltT1' Case Size Extended Cathode Area

45

46

48

49

50

51

52

54

Specification MIL-C -3900oR Qualification Inspection - Group I Tes t 57

i v

LIST O F F I G U R E S A N D T A B L E S (CONT’D)

Table No. Tit le

XXVI

XXVII

xxvm

XXIX

xxx

XXXI

XXXII

XXXIII

XXXIV

xxxv

XXXVI

Page

Specification MIL-C - 39006B Qualification Inspection - Group 11 Examination 58

Specification MIL-C -39006B Qualification Inspection - Group 111 Tes t s 55

Specification MIL-C - 39006B Qualification Inspection - Groilp IV Tests 60

Speci fi cation MIL -C - 3 9 00 6 B Qualification Inspection - Group V Tests 250pF - 10V/7V, T 3 Case (6 Units) 61

Specification MIL-C -39006B Qualification Inspection - Group V Tests 180pF - 25V/15V, T 3 Case (6 Units) 62

specification MIL-C -39006B Qualificatim Inspection - Group V Tests 60pF - 50V!’OV, T3 Case (12 Units) 63

Specification MIL-C -39U06B Qualification Inspection - Group V Tests 30p.F - lOOV/65 V, T3 Case (12 Units) 64

Specificati 19 MIL-C -39006B Qualification Inspection - Sroup IX Tests 6 5

Specification MiL-C -390068 Qualification Inspection - Group VI1 Tests 67

Specification MIL-C -39006B Qualification Inspection - Group V I Tes ts 68

Specification MIL-C -39006B Qualification Inspection - Group VI11 Tests 69

V

L I S T O F F I G U R E S A N D T A B L E S (CONT'D)

Table No. Title Page

XXXVII Specification MIL-C -39006B Qualification Inspection - G=oup VUI Tests 72

XXXVIII Parameter Behavior on Extended 125°C Life Test , Rating 25OpF - 10V/7V, Test Temp. 125"C, Test Voltage 6 Volts ( 2 0 Units) (Remake Units with Extended Cathode Capacitance) 73

XXXIX

X L

XLI

XLII

XLIII

x LIV

Parameter Behavior on Extended 85°C Life Test, Rating 250pF - lOV, Test Temp. 85"C, Test Voltage 10 Volts (51 Units) 74

Parameter Behavior on Extended 8 5 " C Life Test, Rating 180yF - 25V, T e s t Ter-ip. 85"C, Tes t Voltage 25 Volts (5 1 Units) 75

Parameter Behavior on Extended 85°C Life Tes t , Rating 60yF - 5OV, Tea t Tamp. 85"C, Tes t Voltage 50 Volts (102 Units) 76

Parameter Behavior on Exteaded &5"C Life Test, Rating 30pF - 1OOV. T e s t Temp. 85"C, Test Voltage 100 Volts (102 Units) 77

Parameter Behavior on Extended 125 O C Life Tes t , Rating 250pF - 10V/7V, Tes t Temp. 125"C, T e s t Voltage 6 Volts (20 Units) 79

Parameter Behavior on Extended 125°C :-Le Test, Rating 180pF - 25V/15V, Test Temp. 125"C, T e s t Voltage 15 Volts (20 Units) 80

L I S T OF F I G U R E S A N D T A B L E S (CONT'D)

Table No. Title

XLV

XLVI

Page

Parameter Behavior on Extended 125 a C Life Test , Rating 60pF - 5 0 V / 3 0 V , Test Temp. 125"C, Test Voltage 3 0 Vol ts t40 Units) 81

Parameter Behavior on Extended 125 C Life Test, Rating 30yF - lOOV/65V, T e s t Temp. 125"C, Test Voltage 6 5 Vol ts (40 Units) 82

v i i

SECTION 1

ABSTRACT

Over eleven hundred T3 case s ize all-tantalum capacitors

encompassing four ratings were developed and tested in accordance

with the MIL-C -39006 specification. Approximately one-half of the

capacitors were tested as Engineering Evaluat-on units and one -half

tested after the development stage as qualification units.

ra te level IIPtl has been granted by DESC primarily on the basis of

test data generated f rom this contract.

Failur o

The finalized product has all the advantages of the s i lver

cased wet ar.d i c capable of withstanding some reverse potential and

AC ripple current.

-1 -

SECTION 2

SCOPE OF WORK

1 . 0 Purpose

The contractor shall design, develop, manufacture, and qualify

a ser ies of wet-slug all-tantalum capacitors capable of meeting the

performance requirements of MIL-C-39006 and having the same

characterist ics 2.s st,-le SLK65 of MIL-C -39C06 , except a s noted

below. These devices shall be constructed so as to:

a.

b.

Have a hermetic glass-to-metal seal.

Withstand nominal reverse voltages and ripple

currents and remain functional.

c. Prevent formation of internal conductive whiskers

or particles.

2.0 Technical Requirements

2. 1 General DescriDtion

The contractor shall design and deve,Jp a capacitor w :h -. -.

the following general features, 5 --/-a '

- 2 -

y. Detailed drawings of proposed capacitor

construction shall accompany the manufacturer's proposal.

2 . 1 . 1 Case - .

The capacitor case shall be MIL-C-39006 size T 3 .

The case mater ia l shall be tantalum of such structure and purity that

it is capable of being formed to withstand reverse bias of up to two

volts at 125°C.

and anode.

The re shall be no EMF (generated) between the case

2 . 1 . 2 Seal - The cz7acitors shall have a hermetic sea l

consisting of a glass -to-tantalum bond and a tantalum-to-tantalum

weld capable of maintaining a seal-leak rate of no more than

1 x cc/second, at 1 atmosphere pressure differential at 25°C.

2 . 1 . 3 Electrolyte

The capacitor electrolyte shall be such that the

capacitor characterist ics a r e not affected by placing the capacitor

for at least 1000 hours in any position under normal ear th gravity.

2 . 1 . 4 Reverse Bias

The capacitors shall be capable of withstanding

a continuous reverse bias of 2 volts up to 125°C with no pernanent

degradation of capacitance, r?, o r DCL.

- 3 -

2.1.5 Shape and Size

Capacitor s ize , shape and external dimensions

shall conform to the requirements of case s izes specified in MIL-C-

39006, Style CLR65.

2.1.6

The capacitors shal l be manufactured in 4 ra, .A-.Zs*

10, 25, 30 and 100 DC working volts respectively at 85°C.

2. i . 8 Capacitance

The capacitance shail be at l ea s t the lower values

listed in MIL-C-39006, Style CLR65 for 85°C rated voltages of 10, 2 5 ,

50 and 100 volts under Case T3.

acceptable.

than the values l is ted in MIL-C-39006.

Capacitance tolerance of *20'70 *

Capacitance of -55°C and 125°C shall not change more

2.1.9 - Surge Voltage

The capacitors shall be capable of withstanding

surge voltages as follows a t 85°C:

WVDC

10 25 50

100

Surge V o l t a E

11.5 28.8 57.5

115

2.1.10 DC Leak-.ge

The capacitors shall have DC leakage values

l e s s than those l is ted in MIL-C-39006 at 25" anL 125°C and their

respective ratings ,

-4 -

2 . 2 P r o g r a m Description

2 . 2 . 1 Engineering Evaluation

The contractor shal l submit tes t data and reporis

showing successful completion of all of the following tes ts . H e shall

construct sufficient capacitors in case s ize 7 '3 and perforin the tes t s

presented in MIL-C-39006 for Qualification Groups 1 thru V I and

additional tes t s as specified] using the sample speciffed belcv: for

10, 25, 50 and 100 volts capacitors. The contractor shall propose

the quafitity of each voltage needed. Af'ier complet im of each tes t the

contractor shall per form failure analysis and submit .report to MSFC.

2 . 2 . 1 . 1 Groun r and I1 Tests

Group I and Group LI t es t s prescr ibed

for Qualification i n M L - C -39006 wi l l be performed.

2. 2. A. 2 Group LII Tests

The contractor sha l . pzrform Group XI

tes ts ( thermal shock, vibration] tsrnperature cycling, but not salt spral-)

defined i n Table I of MIL-C-39006B for each voltage,

- Leak;ge of

electrolyte af ter each tes t shall be determined by litrllus paper

moistenec i n deionized water. The tes t data shall be recorded,

2 . 2 . 1. 3 Groap IV Tests

The contractor shall perform Group IV

tes ts specified LIL-C-39306 for each voltage rating. Results shall

be recorded.

- 5 -

2.2.1.4 Group V Tes t s

The contractor shall per form Group V

tests specified in MIL-C-39036 for each voltage.

recorded at the various temperatures .

Readings shall be

2.2.1.5 Group VI Tes t s

The cor t rac tor shal l per form life tests

on all capacitors that successfully pass the abote tests. The life tes t

shall be in accordance with Group V I requirements. The contractor

shall perform failure analysis, report t o MSFC, and shal l send all

good capacitors to MSFC. Capad to r s shal l be weighed each time

measurements a r e taken.

2.2.1.6 Ripple Current Matrix

The contractor shall per form a matrix

study or. effects of ripple current on ten properib- biased capacitors of

each of the four voltages specified above, 240 units total, as follows:

85°C 125 "C - 25°C

Condition 1 (120Wz Sinusoidal) 450 n 4 450 mA 450 mA

Condition 2 Sawtooth pulses of Pulse Pulse Pulse f r equencv and amplitude to be determined

The current level should not cause a r i s e of capacikor temperature more

than 5°C a t room ambient.

exceed this level of I R heating.

If cecessary , reduce the 450 mA so as not t o

2

-6-

During electrical tes ts the contractor

shall f i r s t measure Cap, D F , and DCL before any forward bias is applied.

He shall then apply forward rated voltage for some chosen period, sur::

as five minutes, and again measure Cap, DF, and DCL. I’,ots f o r Cap,

D F and DCL before and after forward bias ;Cd l be made at 0, 120,

500, 1000, 2000 and 4000 hours, and curves drawn.

--

At least one l i t rms check shall be

made during this testing, and final visual inspection shall be made.

Two capacitors f rom each rating shall

be opened and examined for internal deteriorktion (whiskers, leaks,

cracks, etc.).

Remaining capacitors shall be sent

to MSFC.

c 2 . 2 . I . 7 Reverse Bias

The contractor shall perform matrix

studies at a reverse voltage of -2 volts using 10 each of each voltage

rating made with at least three cathode formation voltages (such a s

3 V , 5 V and 7V) as indicated below.

-7-

Nominal Cathode Formation Temperature

25°C - 85°C lZ5OC 7

Voltage

3.0 10 each 10 each None voltage voltage rating rating

5.0 Same None 10 each voltage rating

7.0 None 5 ea@ 1OV 10 each 5 ea@ 100 V voltage

rating

This is a total of 210 capacitors.

These tests shall run for 2000 hours, with

electrical tests (Cap, DF, and DCL) taken at 0 , 250, 500, 1000 and 2000

hcurs. See Para. 2.2.1.6 for Electrical Test Method. r

2.2.2 Demonstration of Capability to Mass Produce and Qualify

When tes ts in 2 .2 .1 indicate to MSFC a capacitor

of stable design and of good workmanship and quality, the manufacturer

w i l l produce a minimum of 600 s ize T3 capacitors and subject them to

screening and qualification tes ts as specified in MIL-C-39006B for

Style CLR65. The subgroups should be divided using the full total

specified, however only the T3 case s ize will be used. That will be

a minimum of 594 devices for the voltage classes specified in

MIL-C-39006B. All limits and tes t conditions shall be those specified

in MIL-C -39006B.

-8-

After the successful completion of the above

tests and inspection, the all-tantdum capacitor in the T j case size

in the voltage ranges specified in MIL-C-39006B will be considered

qualified for MSFC use in Critical Space Hardware. These capacitors

wi l l be sent to MSFC after completion of tests.

2.3 Reports Requirements

2.3.1 Monthly Progress Reporat

The contractor shall have this report prepared

for distribution by not later than the 15th day of the month following

the reported period. Reports shall be in narrative form, brief and

informal in content, and w i l l include, but not be limited to the following:

a. A quantitative description of overall progreg . ;

b. An indication of any current probler- .vhich may impede performance, and prop, zd corrective actions , and:

C. A discussion of %e uork to be performed during the next mcmthly reporting period, including the approximate man hours and dollar expenditures.

d. Expenditures t o date and forecast of funds required for completion. a detailed discussion of funding deviations or problems.

This should include

2.3.2 Final Report

2.3 .2 .1 The final report shall be narrative i n

form and include, as applicable, the following:

-9-

a.

b.

C.

8.

e.

Initial program concepts;

Changes in program concepts and factors causing the changes;

Problem areas and necessary corrective actions;

An overall evaluation of the program and the program results, and;

Recommendations.

2.3.2.2 A rough draft of the final report shall be

submitted for approval to the Contracting Officer within twenty (20) days

after completion of the Scope of Work. Comments w i l l be furnished to the

contractor wit& fifteen (15) days of receipt of the draft copy of the

report. Upon receipt of the draft copy in its approved form, the

contractor shall reproduce and distribute it as directed-in Para. 2.3.5.

2.3.3 Report(s) Preparation Instructions

The above report(s) shall be submitted under a

title page showing the following information:

a. Contractor's name and address, including segment generating the report.

b. Title of report, including period covered, when applicable.

c. Author(s)

d. Type of report and contract number

e. Date of publication

- 10..

f. Prepared for George C. Marshall Space Flight Center, Marshall Space Flight Center, Alabama 358 12

g. fnclude an abstract

h. All technical reports. wblications, and wisuol presentations submitted to MSFC under this contract shall use the International System of Units as the preferred primary system. Ekpression in SI unite alone would obviously impair communications or reduce the usefulness of the report to the primary recipients. When both systems of units are used, SI units are to be stated first and customary units afterwards, in parentheses. In each such case, the publication shall state which system of units was used for the principal measurements znd calculations. SI units are specified in National Bureau of Standards Technical News Bulletin, Vol. 48, No. 4, page 61, April 1964; and defined in NASA SP-7012, The International System of Units , Physical Constants, and Conversion Factors, revised 1969. Both of these documents can be obtained from the Superintendent of Documents, U. S, Government Printing Office, Washington, D. C. 20402.

2.3.5 Reports Distribution

Copies of report(s) other than those intended for the

Defense Contract Administration Services District, shall be distributed

to National Aeronautics and Space Administration, George C. Marshall

Space Flight Center, Marshall Space Flight Center, Alabama 35812 to the

codes 2nd in the quantities indicated below. A copy of the transmittal

letter showing distribution of the reports shall be furnished to A&PS-PR-M.

-11-

Monthly Quarterly Final - C d e s

A&=-PR-RDMI 1 0 0

A&=-MS-D 5 AQPS-TU 0 SQE-QUAL-QT 3

S&E-QUAL-OC 1 S&E-ASTR-RNI 1 StE-QUAL-E (Davis) 1

1 Totals 13

W. R. Barlow

Applicable DCASO -

*Plus reproducible copy.

5 1 1W

1 1 1 1

20 -

5 1

10

1 1 1 1

20 -

- 12-

SECTION 3

DISCUSSION

A. Development Phase

(1) Special Tooling and Equipment

'It should be noted that a l l tooling and equipment a r e

funded solely by the Sprague Electr ic Company.

An indexing welding fixture was designed in the

ear ly par t of September, 1973 to be used in the

hermetic sealing operation of the can rim and outer

seal header. The welding method employed was that

of overlapping TIG welds.

Problems with cracked glass plagued this operation

and required severa l modifications in the mechanical

and electrical design of the indexing fixture.

fifth month evaluations revealed that the efficiency

By the

and reproducibility of the system was improved to the

point where a total of 218 capacitors were welded with

-13-

acceptable quality and were scheduled for use in the

evaluation of processes in the Engineering Evaluation

Phase of 5 . ~ contract.

Several refinements were subsequently made in the sys tem

t o facilitate the welding operation and this system was

not finalized until the eighth rr-onth of the contract.

(2) Procurement of P a r t s

a. Tantalum Cans

Several dozen prototype drawn tantalum cans were

obtained f rom a potential supplier.

evaluation of these tantalum cans indicated that the

supplier has the necessary technology t o produce

tantalum cans having the properties required in this

contract. Subsequent to finalization of the appropriate

par t specifications, procurement was initiated for a

sufficient quantity of tantalum cans needed to complete

this program.

Results of an

Two shipments of drawn tantalum cans were received

during January 1974.

was used for evaluation including welder set-up and

cathode studies.

The f i r s t of these shipments

The second shipment was used tc

- 14-

refine processing techniqzes and to construct par t s

fo r the Engineering Evaluation portion of the contract.

The remainder of the tantalum cans to fulfill the

requirements of this contract were received by

March 1974. However, due to the quantity of cans

used i n developing a solution to the hermetic seal

problem and to alleviate the possibility of a future

shortage, 200 additional cans were procured i n

December, 1974.

b. Tantalum Shells.

The tantalum shel l portion of the all tantalum

capacitor construction is a drawn metal par t used

in the construction of the tantalum-to-glass-to-

tantalum seal,

of the sea l and is welded to the capacitor case. The

tantalum can is distinguished f rom this par t in that

it comprises the cathode and contains the working

electrolyte for the system. Initial attempts to procure

the tantalum shell were successful. Subsequent

attempts, however, resulted i n cracks and excessive

metallurgical s t r e s ses . These properties precluded

It is that par t which forms the periphery

-15-

the use of these par ts in seal construction.

Attempts to alter metallurgical properties were

futile.

problem to the surface condition of the tantalum

Extensive evaluation finally traced the

stock. A cooperative program between the Sprague

Electric Company, the shell manufacturer and the

material supplier was initiated in an attempt to solve

the problem. Numerous t r ips by both Sprague

representatives and the mater ia l supplier were

made. A decision was then made to physically

t rea t the surface of the tantalum stcck by established

Sprague processes in order to improve drawing properties.

Several samples of specially prepared tantalum stock were

prepared and submitted to the shell manufacturer.

The treated tantalum was found to perform infinitely

better than the untreated stock.

scheduling was adhered to and sufficient par ts to

manufacture the remaining engineering evaluation

par t s were put through the first stage of shell manu-

facture.

examined by the metallurgy department of the Sprague

Electr ic Company and resubmitted to the shell manu-

facturer for finishing oper G t' ion.

Preliminary program

The partially completed shells were then

Two s eparat e pre -drawing t r e atrnent s we r e

tr ied, and the resulting parts evaluated. Both

treatments resulted in the satisfactory drawing of

shells with one method preferred chemically. Seals

were manufactured f rom the shells using the

perferred treatment method and these were

used to finish additional capacitors.

supply was cri t ical , but the drawing problem was

solved.

The shell

During the December 1974 report period 1700 shells

were received which supplied an adequate number of

shells for the contract completion. However, the

delay incur red her e unavoidably delayed the

completion of the contract by a minimum of two

months.

c. Glass Insulator (Tantalum Shell)

The extruded glass for use in the glass-to-tantalum-

to-glass sea l was received in mid-December, 1973.

Glass preforms were prepared f o r use in seal

evaluations.

d. Chamber Top Retainer

Initial experiments with the prototype tantalum

-17-

e.

cans revealed that it was necessary to modify the

top retainer. Hence, redesigned top retainers w e r e

ordeydd and received during December, 1973, These

par ts , however, along with the bottom retainer required

slight modifications for the purpose of a better fi t . The

modified par ts were subsequently procured.

Construction of the Engineering Evaluation parts

utilized the original par t s which did not a l ter the

capacitor performance o r capabilities.

Specifications and Drawings

Specifications and drawings pertaining to the

component capacitor par ts were completed by

March, 1974.

Cathode Studies

LCeveral tantalum powders and processing cmditions

(identified i n Figure 1) were evaluated for producing a

suitable cathode system.

the percent cathodic efficiency, plotted against cathode

Figure 1 graphically represents

formation voltages for these cathode systems,

cathodic efficiency is defined as:

The percent

Percent Cathodic Efficiency VS

Cathode Formation Voltages For Various Cathode Syste

100

90

80

70 ?'o CatLodic Efficiency

60

50

40

30

20

10

Figure 1

-19.

Where CAE is the capacitance of a standard 10 volt

rated anode measured ia series with the experimental

cathode system; and CAS is the capaa tance of a standard

10 volt rated anode measured in se r i e s with a platimted

silver cathodz. The cathode sys tem F which utilized an

ultrahigh CV/gram powder identified in Figure 1 represented

.e best 'obtainaole cathode performance. Results of

these cathode stL*dies indicated that presently available

tantalum powders could provide monometallic cathode

systems which will permit the contract capacitance

objectives to be met at the specified cathode formation

voltages of 3, 5 and 7 volts.

Preparation and processing parameters fo r the mono-

metallic tantalum cathode were finalized and implemented

during Febrtlzry 1974.

cans were processed with good results using thr-se

techniques.

-9 significant number of tantalum

A patent application for th is processing technique was

' filed on August 22, 1974 under number SN 499750,

entitled "Method for Preparing the Container of an

Electrolytic Capacit , I

-20-

The above processing technique was obsoleted by a more

improved, pressed cathode l iner method. The l iners a r e

pressed and sintered in the car.. In this man2er the l iner

weight and density can be increased and controlled within

5-770 thereby yielding higher and more uniform capacitance

values between cans. I

Five capacitors rated at 560pF - 6 V which were made with

pressed cathode l iners were vibration tested up to the 80G

level, as a means of determining the durability of the

cathode system, with satisfactory results. These units were

vibrated at 20G1s, 40G's and 60G's in each of two directions

for 1 hour/direction ahd with the frequency modulated between

10 and 2000 hertz. At the 80G level the same procedure was

followed a s above but then the capacitors were given 3 hours

of additional vibration for a total time of 8 hours. At this

point testing of these units ceased.

Listed in Table I a r e the individual data fo r each capacitor

before test , after shock (100G's) and after vibration at 80G's.

The decrease i n the dissipation factor (DF) after the 80C

vibration tes t was looked at as a means for lowering the

equivalent se r ies resistance (ESR) however these results could

not be repeated with other units tested similarly.

-21-

TABLE I .

CATHODE LINER DURABILITY TESTING (560yF - 6V)

Before Tes t Post (IOOG) Shock Post Vibration (80G) DF DCL Cap DF DCL UnitNo. Cap. Dz DCL Cap -

1 574.1 23.4 .0055 560.1 26.8 .005 592.4 18.2 1.4

- -

2 563.0 23.8 -0075 549.5 26.2 .0130 582.6 16.5 1.4

3 569.6 26.6 .0090 556.7 25.1 .0135 592.6 16.4 1.5

4 571.5 22.4 .0062 557.6 25.6 .0075 593.5 17.3 1.0

5 567.8 24.4 .0048 561.0 28.2 .0084 599.9 18.3 1.3

Cap = Capacitance in yFd D F = D;-ssipation Factor in 70 DCL = Direct Current Leakage in PA.

-22 -

(4) Capacitor Design

During the first quarter sevaral prototype 250pF - 1OV rated

tantalum capacitors which were constructed (without the

hermetic seal) using cathode sys tem F were evalvated for

electrical characterist ics. After assembly the par t s were

processed according to standard Sprague Electr ic Company

processing techniques and measured. The typical electr ical

parameter values for these capacitors were as follows:

a. Capacitance = 263pF

b.

c.

d.

Leakage Current @ 1OV = 2. SPA

Equivalent Ser ies Resistarice = 1.3 ohms

Leakage Current @ -2 V = 0.39@.

Sever21 prototype capacitors were constructed during the second

quar te r period to evaluate cathode systems and the welding

fixture.

were necessary to ensure compatibility with processing

pa i -me te r s .

These evaluations indicated that 2 ?sign modifications

Difficulties encomtered i n containing the acid

electrolyte during welding necessitaLed modificat:ons to the

top retainer portion of the capacitor. Evaluation of the modified

design proved to be effective in containing electrolyte during the

welding operation and was incorporated into the finalized

capacitor design.

Evaluatim capacitors.

This design was used in the Engineering

-23-

Ten 60yF - 50V capacitors were consigned to Marshall Space

Flight Center (L. Hamiter) for evaluation.

B. Engineering Evaluation Phase

(1) Tes t Specification

Tes t specificatims outlining test procedures and sequences

to be used during the Engineering Evaluat iw an-! Qualific-t;m

Testing portions of this contract were prepared and issued

to appropriate personnel by the Sprague Quality As mrance

and Reliability Department during the first quar te r of t h i s

contract.

Work on the Engineering Evaluation Phase of the contract was

initiated i n mid-January, 1974.

Processing of par ts necessary for use i n the Engineering

Evaluation began, including the processing of the cathode

and anodization of tantalum pellets.

i n procuring tantalum sea l shelia resulted in a delay in the

execution of this portion of the contract. Several Engineering

Evaluation tes t sample capacitors were randomly selected

f rom parts being processed and evaluated.

evaluation was to characterize the parts for electrical , temper -

ature and environmental performance.

evaluated were the 250pF - 10VDC and the 60 pF - 5 0 V D C units.

The difficulty encountered

The purpose of this

The two ratings

-24-

Electrical and temperature characterist ics for the 250pF - lOVDC and 60pF - 50VDC ratings a r e shown in Tables LI

and ILT respectively. Al l parameters were within the Specifi-

cation MIL-C-39006 limits except for two par ts which slightly

exceeded the -55OC capacitance change requirement. Two

parts do not meet initial capacitance specification (i. e. *20%).

All other performance parameters for the 6OpF - 53VDC

rating were within specification limits.

Several units of the 60pF - SOVDC rating were vibration

tested per Specification MIL-STD-202 Tes t Condition ttDtt ,

wi*thout voltage. All par ts were fcund to meet the electrical

performance requirement after vibration testing. These

dpta a r e presented i n Table IV.

of this test demonstrates the capability of the cathade coating

to withstand severe vibration without adversely affecting

The successful completion

electrical performance.

Temperature cycling performance for the 250p.F - lOVDC$

rating ( -55'C to +125"C after 30 cycles) i s presented i n

Table V. Electrical performance was not affected adversely

by cycling tests.

of meeting Specification MIL-C -39006 requirements.

This performance indicates the capability I

Q

0

0

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rr) I

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c w E

u 0 In

ru r(

u 7 * E

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-27-

TABLE IV

VIBRATION TEST RESULTS PER MIL-STD-202

60pF - 50VDC RATINGS

Reading Initial Reading After Vibration Test

5 OV 5 OV ESR DCL C a p - - ESR DCL - Unit # C a p - -

1 2 3 4 5 6 7 8 9 10

60.1 .93 b 06 55.3 1.2 . 06 61.9 -95 . O S

60.7 1.0 .05 55.2 1.2 . 05 54.6 1.2 .05 54.3 1.9 .09 63.0 .92 . 05

57. 1 091 1.5

59.9 1.0 b 2

60.2 .90 .I3 55.4 1,l . 13 57.3 .92 1.2 .

60.0 1,O 1,3 60.8 .94 .13 55.3 1.2 0 1 1 54.4 1.2 011 54.7 1.8 . 12 63.0 092 0 1 1

62.0 b87 014

Cap = Capacitance in pFd. ESR = Equivalent Ser ies Resistance in ohms. DCL = Direct Current Leakage in FA.

TABLE V

TEMPERATURE CYCLING PERFORMANCE ( -55°C to +125'C) 250~1.F - 1OVDC RATING

Post 10 Post 20 Post 30 Temperature Cycles Temp. Temp. Tes t

Initial Cycles Cycles 1 ov 1 ov 1 ov

Cap ESR DCL CGL DCL Cap ESR - - - Unit #

291 . 76 . 56 . 68 -88 274 -63 302 -77 2.6 6.1 6.2 279 1.0 363 -86 .54 1.0 1.6 34 1 . 74 217 . 77 . 43 . 70 -54 212 . 80 334 -68 42 . 75 -58 313 -56 314 -76 2.8 . 69 -59 301 . 66 308 . 75 . 43 . 75 .55 298 .63 252 .61 * 9 2 3.1 .81 251 . 59

1 ov DCL

86

- 6.0 1.4 . 74 . 84 . 71

. 98 2.6

Reag e 1 ov DCL

. 52 . 71

.49 . 45 . 53

.43

.64

.47

-

Cap = Capacitance in pFd. ESR = Equivalent Ser ies Resistance in ohms. DCL = Direct Current Leakage in PA.

-29-

Work continued on this tes t phase units with the 7 volt

cathode groups completed during April 1974.

48 hour voltage conditioning, (Group I of the MIL-C-

39006 Specification) was performed during the May 1974

report period. These tes t data are reported in Table VI

under the 50 unit section.

The

All initial parameter< with the exception of two DCL

levels i:- the lOOV rating and one high capacitance

par t i n the 25V rating a r e within MIL-C-39006, style

CLR 65 limits.

Twenty-six units f rom each of the tes t ratings, 250pF - lOV, 180pF - 25V,- 60pF - 50V and 30pF - lOOV, were

placed on a Group VI, 2000 hour, 85°C life test.

capacitor weights were measured at each readout point.

This testing was completed by November 1974 and the

tes t data a r e reported i n Tables VI1 - X for the 1OV - lOOV groups resTectively.

Individual

Additionally capacitors f rom each of these ratings were

subjected to the Qualification Inspection testing for Group

III (Shock, Vibration, Salt Spray and temperature cycling),

Group I V (Terminal Strength, Moisture Resistance, Surge,

Sleeve Tes t and Cold Temperature Storage) and Group V

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(Stability at Low and High Terr,peratures). The

summarized test data for these Groups a re reported

in Tables XI - XVI.

During the August 1974 report period a serious problem

relating to the capacitor hermeticity came to light.

Leak testing of random samples of capacitors per

MfL-STD-202E, Method 112B, Condition C, procedure IIIa

revealed fine leaks in 11 of 12 units tested.

leaks (Method A) or electrolyte leaks were detected.

No gross

This situation prompted an examination of the entire

seal situation. As a result all the completed units on

hand, with the exception of those at the control lab, were

tested for hermeticity.

gross leak test (MIL-STD-202E, Method 112B, Condition A)

failures were noted.

prior to Condition C to minimize contamination of the Mass

Spectrometer.

leaks after gross leak screening, and 111 good seals.

represents a 44.6% yield on seals out of the 249 units tested.

Seal problems were narrowed down to sensitivity to welding

heat, with the further observation that the condition of the

tantalum surface of the shell prior to fusing affected the

degree of sensitivity.

One new development was that

Condition A was used as a screen

The results were 114 gross leaks, 24 fine

This

-36 -

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Changes in the sea l fusing and welding processes, in order

to minimize the heat sens,tivity, resulted in a decrease

in units failing the s e d tes t s f rom 54% to only 7%. Since

shells were in shor t supply only 130 seals were available

for welding with the new processing methods. These

130 seals resulted in 121 units successfully completing

the seal tests. The 770 loss represents nearly an eight

fold decrease in the loss ra te f r o m faulty seals.

However, due to further problems in the welding of the

hermetic seal a comprehensive program, including the

investigation of l a se r welding, was started.

there were sufficient shells and cans on hand at this t ime’

Fortunately

to allow a thorough and methodical investigation of the

problem. Significant progress on this problem was made

during the seventeenth report period and by the eighteenth

report period it w a s concluded that l a se r welding was the

solutior, to the hermeticity problem.

l a se r welded with a greater than 9770 hermetic yield.

Over 500 units were

Due to losses encountered during the welding and hermetic

sea l difficulties i t was necessary that a few additional units

be assembled to complete the ripple matrix units. These

units along with the units for completion of the reverse

voltage tes t matrix were completed by May, 1975. The

-43-

voltage conditioning data for there groups a r e reported

in Table VI under the two 20 unit headings. The ripple

tes t units were sent to NASA on May 13, 1975 for testing.

The 7 volt cathode formation group began the 2 volt

reverse testing at 85°C and 125°C during October.1974.

Ten capacitors f rom each of the four ratings were sub-

jected to the 125°C temperature and 5 units f rom the

1OV and lOOV groups were placed on the 85°C test.

This testing was completed by Janaary, 1975. The

summarized tes t data a r e reported in Tables XVII

and XVIII for the 85°C and 125°C temperature testing

respectively. These data indicate that a 7 volt formed

cathode i s capable of withstanding intermittent voltage

reversals in the order of 2 volts.

that a stability reage at the 85°C rated voltage and

It should be noted

temperature fcr 16 hours was performed at the end of

each readout interval.

The 3 volt and 5 volt cathode formation groups were

completed by May, 1975 and commenced the 2 volt

reverse bias matrix testing,

by August 1975 and the summarized test data a r e reported

This testing was completed

-44-

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formations proved to be saiisfactory and the 3 volt cathbde

formations to be marginal for the required 2 volt reverse

capability.

A summary of all the Engineering Evaluation Testing i s

given in TaLle XXIII.

Dcring August 1975 reports were received f rom NASA that

several capacitors were showing excessive Capacitance loss

duricg ripple voltage testing. Evaluation of the data indicated

that this bahavior was probably dependent upon initial cathode

capacitance. A higher cathode capacitance appears to be

required than i s necessary on1.y to support the anode

capacitance to obtain the desired total initial capacitdnce.

Hence, 6OpF - 50volt capacitors with extended cathode

capacitances adequate to cope with the ripple. current

encountered in the testing were constructed for retestin;

t o confirm that low cathode capacitaRce was the problem.

Ten of these 60pF - 50 volt units to replace the ten units

showing excessive capacitor -5ange on ripple test were

shipped to NASA for the retest during November 19’15.

Analysis of t -vo capacitors of each rating (250pF - lOV,

180pF - 25V, 60yF - 50V and 30yF - lOOV) failing the

-47-

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TABLE XXLII

ENGINEERING EVALUATION TEST TEST /SAMPLE PLAN

(UNITS/TEST)

25OpF - 1OV 18OpF - 25V 60pF - 50V 30pF - IOOV Test Report Test Report Test Report Tes t Report

Test Routine N ~ . ( ~ 8 0 4 ) N ~ . ( ~ 8 0 5 ) NO. ( ~ 8 0 3 ) pro. ( ~ 8 0 2 )

1. Group1 Voltage Conditioning DC Ledcage Capacitance Dissipation Factor

2. GroupII - Visqial & Mech. (Internal) Vis.ial & Mech. (External)

3. GroupIII Shock Vibration Temperature Cycle

4. Group IV So Id e r abili ty Terminal Strength Surge Moisture Dielectric Sleeve Test Insulption Sleeve Test Low Temp. Storage Seal

5. GroupV Stab. Low & High Temp.

6. GroupVI Life Test

7. 2 Volt Reverse Bias Matrix

Voltage Cathode Formation

3.0 Volts ( 2 5 ° C ) 3.0 Volts (85°C) 5 . 0 Volts (25°C 5.0 Volts (125'C)

7.0 Volts (125°C) 7.0 Volts (8:,"C)

90 90 90 90

2 75

3 3 3

3 3 3 3 3 3 3 3

3

26

10 10 10 10

5 10

85 85 85 85

2 . 77

3 3 3

3 3 3 3 3 3 3 3

3

26

10 10 10 10

10

85 85 85 85

2 75

3 3 3

3 3 3 3 3 3 3 3

3

26

10 10 10 10

10 -

YO 90 90 90

2 75

3 3 3

3 3 3 3 3 3 3 3

3

26

10 10 10 10

5 10

NASA ripple current tes t f o r capacitance loss was

undertaken and completed in December, 1975. In

general it was shown that the capacitance loss was

due to an increased thickness in the cathode dielectric

oxide layer as is evident by a color change in the

cathode lining. A detailed report including colored

photographs showing the cathode colors were sent to

NASA.

The ten 60yF - 50V remake capacitors completed

2000 hours of ripple current testing at NASA by

April 1976.

for the electrical parameters of capacitance, dissipation

factorand room temperature DC leakage as we11 as

capacitance stability.

in the parameter data summary table.

The test data a r e reported in Table XXIV

The tes t conditions a r e stated

It will be noted that all capacitors experiecced some

capacitance loss over the tes t interval, however, wi th

the maximum loss being -6 .670.

the maximum capacitance loss was -42%. The failure

mode he re was apparently eliminated via the extended

cathode surface area.

With the original units

-53-

m

Q)

In

In

* I

n)

*

F-

i

In

&

vi I

m

vi

00

0

v1 2 z 3.

w

4 Y z 0

Tr I

E 0 &

trl

0

ln I

0

m

3

al N

Q; m

I c (6

.C(

a" 0

m

pr) I

0

U

m

c.)

0

C

N

I

A

m -

N

d) 9

0

N

c)

5

0

W

CJ Q

)

I

m

4

9

r

4

0

4

00

00

00

*"a

-4

2," co 9

ui

N

0

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2.

F-

0

Q 1

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I .. 0

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0

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Y

.CI

W

E

0 u

h

e a

(d

u Q

u n n

rrl. Y

(d

0

-54-

The initial D F values reported at NASA s e e m to be

out-of-line with the values measured at Sprague pr ior

to shipping the units.

more reasonable when one compares them with the Sprague

init ial values.

The 2000 hour D F values a r e much

C. Qualification Tes t Phase

Initial processing of the Qualification Tes t Phase capacitor

parts began in June 1974. During the next 3 - 4 months the

development of the hermeticity problem and the unavailability

of materials resulted in a prolonged period of inactivity in this

phase.

By December 1974 approximately 7570 of the qualification

tes t units had been processed to the point preceding the hermetic

s e d closure. Once again the hermeticity problem delayed

further progress on these units for a couple of months.

HJwever, by April 1975, 594 tes t capacitors had been

delivered to the Sprague tes t facility for commencement of

this tes t phase.

During May 1975 the qualification testing had proceeded as

follows :

Group i testing was complete. One unit (60~F - 5 0 V )

w a s replaced as a result of high DC leakage. 1-

- 5 5 -

remained within the required 2.0p.A range but

deviated greatly f r o m the remainder of the

units (see Table XXV).

Group II and Grcup 111 tests were completed

without fa i lure (see Tables XXVI and XXVII

respectively).

Group N had been completed without fa i lure (see

Table XXVIII),

Group V had been completed without failure ( see

Tables XXIX - XXXII for the lOV, 25V, 50V

and lOOV groups, respectively).

Group VI was scheduled for the 1000 hour readout

on 9 June 1975.

successfully passed.

The 250 hour readout was

Group VI1 was scheduled for completion about

4 June 1975.

Group VI11 was scheduled for the 1000 hour readol;t

on 9 June 1975. The 250 hour readout was

s u cc e s s f ully pas s e d . Group IX had been completed without failure ( see

T able XXXIII).

The Group VI1 testing was completed during the first week of

June 1975. The tes ts were completed successfully, and in

- 5 6 -

I I

I I

am

E

E

aa

&

&

100

00

uu

I I

I I

1

cr) O

Nc

r)

co

rn

01

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N .

..

cr) N

cv

940

9

4c

;d

I

N

mN

e

P-0

d4

dl I

rr)

>

-57

-

TABLE XXVI

Rat ing

SPECIFICATION MIL-C -39006B QUALIFICATION INSPECTION - GROUP II EXAMINATION

A r e a Visual and Mechanical Examination

250pF - 1OV T 3 Case

180pF - 25V T 3 Case

60pF - 50V T 3 Case

30pF - lOOV T 3 Case

of Exam

Internal D eg rad ati on Dimension; Workmanship Markings

Internal Degradation Dim ens ions W orkmanship Markings

In t e rna l D e g r ad ati on Dimens ions W orkmanship Mar king s

Internal Degradation D i m ens ions W orkmans hip Markings

Int e r nal (1 Unit)

Conforms - -

Conforms - - -

(2 Units)

Conforms - - -

Conforms -

External (98 Units)

- Conforms Conforms C onf o r ms

- Conforms Conforms Conforms

(196 Units)

- C onf o r m s C onf o r ms C o d c r m s

- C onf o r m s Conforms Conforms

- 5 8 -

-0

9

NQ

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io

m'o

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J~i~rrJAG

PAGE IS

OF POOR QU

m

,-

-0

3 -

addition all 18 Group VI1 units successfully passed the "for

information only" fine leak tests requested by Dr . Holladay

of NASA (see Table XXXIV) .

By the end of July 1975 +he Group VI and Group VLII 2000 hour

l i fe tests at 85°C and 125"$, respectively, had completed

testing with the final readcuts made during August.

The Group V I life tests were completed without fa i lure ( see

Table XXXV).

125°C seve ra l capacitance change (increase) failures were

encountered in the lower voltage grcups (10 and 2 5 volt units).

The 50 and 100 volt units passed satisfactorily (see Table

XXXVI).

problems encountered in the ripple test portion of the

Engineering Evaluation Phase, the problem appeared to be

due to insufficient initial cathode capacitance. A sufficient

number of 250pF - 10V ra ted capacitors with extended

cathode capacitance adequate enough to eliminate the

capacitance drift failure mode Segan construction.

In the Group VI11 life tes ts conducted at

As in the case of the capacitance change

Meanwhile, the l ife tes t units \vhich completed the 2000 hour

life tes ts were returned to the Sprague Control Laboratory

.iere the 8 5 ° C and 125°C life tes ts n-ere car r ied on urdtil

a total of 10, 000 hours had been reached.

-66 -

> 0

4

> In

hl

9

-67-

mo

m

uuu

d

d

t I

10

1 I

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m 0

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11

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>

>

ORIGIN& PAGE IS

- OF POOR QUALITyI -08 -

N

I,

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mu

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a

~~

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--

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.

..

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L

"- 1

, I

-,

I

I,

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I,

.,

,

I I

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.-'I-

By November 1975 the 250p.F - ! O V / 7 V , remake units with

the extended cathode capacitance were completed and had

begun 125°C life testing.

achieved during April 1976. A comparison of the tes t data

between this group and the original tes t group of this rating

is given in Table XXXVII.

the extended cathode capacitance had stabilized the capacitance

parameter during this tes t .

to continue to 10, 000 hours.

contract these xnits had achieved 6000 hours of tes t and

exhibited excellent parameter stability.

electrical parameter readout was taken at this point and

i s repcrted i n Table XXXVIII.

The 2000 hour tes t m a r k was

It is unequivocally clear that

These units were placed back on t e s t

By the completion date of this

A complete

A follow-up report t o this contract with the summarized

1 0 , 0 0 0 hour data wi l l be made around March 1977.

The 10, 000 hour, 85°C extended life tes t mark was achieved

during September 1970.

capacitance, dissipation factor, 2 5 ° C DC leakage and 85’C

DC leakage were obtained on each unit.

reported in summarized form i n Tables XXXIX - XLII along

with the calculated values for capacitance change ana the standarc!

de v i ation.

Complete parameter readouts of

These data a r e

- 7 1 -

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9

3

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<- 0

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d

a ;I z.2

Il

l.

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c rz n. n n

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-76-

A

VI

E-( c(

z 3 tu 0

d -

uc3

O

<

m

3030 030 3000

oc

a0

o

=.

o3

oc

oo

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00

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530

300

LP

30

30

03

0

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030 303

3c=

300

N0

30

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m 0

a

c.

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- W

W c,

n

All capacitors successfully completed this test. However,

one unit in the '00 volt grocp exhibited a hot DC leakage

value an order of magnitude higher than the maximum

8,000 hour value. This value was still within the MIL-C-

>9O(ib /22 specification allowed maximum vahe .

The 10,000 hour readout for all four ratings on the 125°C

extended l i fe test occurred during October 1976. The low,

average and high data for the electrical parameters of

capacitance, dissipation factor, 25°C DC leak3ge and 125'C

DC leakage for each grou2 has been reported in Tables

XLUI - XLVI. Additionally the standard deviation statistic

for each parameter 'has been included.

The three lower v o l t q e groups exhibited failures for

excessive capacitance increase at the end of 6,000 hours

of test an?. that every group had a failure for excessi--?

capacitance increase at the end of 10.000 hours of test.

The nctrrher of capacitors failing decreased nith increasing

2ated potential as indicated Lelow:

Number of Cnits with

Rating r o AC > 1c-7

10, uC)O Hours - 6, O O C Hours

25Q 10 v 181 18 180yr - 25v 17/2@ 9 J y F - S @ V 1 / i o 30+F - lOOV O i 4 0

18/ 18 ?0/20

2 / 4 0 1 ;40

-78 -

5.

0

LC

9

e s

z 3 N, 0

"d

0.

->

&G

I o

m0

3

01

0 oooc so00

03

3c

oe

=o

c

GC

I

CO

D

0,S

o

CO

C

303

N3

03

C3

OC

0

00

L

r3

C3

03

30

coo

00

0

030

.a 3-

L -

8 .d

Y

m

c a .* a .r(

2

cl 2

-80-

A

VI

e z 3

m

0

d.

VI - f9 I

0 9

N

Il

l.

N

d

-P I

t.

N

In

Il

l 0

11

11

1l

11

0

W

d

CI

.= 3

U

C

a Li m R

d

03

3

.C(

c) a

m a .d

3

u c u n I

CL

m

z 3

z 5 0

m

4

r- I

ll

.

0

4

4

11

.

N

m

Il

l.

0

30

Il

l.

0

4

11

11

11

11

In

c(

0

4 eLn

bN

CS

0

00

0

4-eo

NQ

'

X*

S3

00

N

ca

03

)N

-ln*

OC

Pr'r

-

30

0-

-

-L

n4

--

-+

--

N'--

oc3c 00-000300

..

..

.

..

.

..

..

..

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.

tJ

0

00

03

300 3300

03

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0003

300 000

coo

933

Lr

30

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(

.a

000 030

003

330

-.le

3

A

3

0

C

(d

Y

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2 1. rj L'

v

>

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G

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a-

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c3

oc

3

3C

C

390c

-82 -

However, i t was pointed out ea r l i e r in this report that

this failure mode was eliminated v i a the extended cathode

surface area as evinced by the remake groups performance

through 6 , 000 hours as outlined in Table XXXVIII.

MSFC Meeting

A meeting was held on Wednesday, March 1 3 , 1974 at the

Marshall Space Flight Center between representatives of

the Sprague Electr ic Company and NASA. Persons who

attended included the follouing:

Sprague Electr ic Company NASA

John L. Moresi Dr. A . M. Halladay

John P. Moynihan M. Nowakowski

Franc is J. Garnari F r e d Laracuente

The purpose of this meeting was to discuss the progress of

this contract and consign seve ra l prototype capacitors to

NASA for testing.

design and monometallic cathode assemblies Lvere d i scusse i

and examined.

were measured by NASA during the meeting.

agreed closely with readings taken by thz S7rague Electr ic

Constructional aspects of the capacitor

2ctricA parameters of the prototype capacitors

The readings

Company.

could meet initial hii l i tary Specification l imits as well as

withstanding - 2 V reverse voltage.

These prel iminary tes ts indicated t52t the par ts

- 8 3 -

SECTION 4

WORK TO BE PERFORMED DURING THE NEXT REPORT PERIOD

Contract completed.

4 -

SECTION 5

EXPENDITGRES AND FORECAST

Total contract funds were utilized i n performing this

contract effort.

-85-