ADVANCED JOINING TECHNOLOGIES FOR THERMAL PROTECTION · PDF fileADVANCED JOINING TECHNOLOGIES...

ADVANCED JOINING TECHNOLOGIES

FOR THERMAL PROTECTION

SYSTEMS

ADMACOM workshop

14 - 15 September 2016

Regione Piemonte - Bruxelles

Dr.-Ing. Jorge Barcena

Industry and Transport Division

TECNALIA Research & Innovation

C. Jimenez, S. Florez, B. Perez, X. Hernandez, K. Mergia,

K. Triantou, V. Liedtke, C. Wilhelmi, W. P.P. Fischer,

J.-M. Bouilly, A. Ortona and B.Esser

MOTIVATION OF THE WORK

APROACHES USING BRAZING TECHNOLOGIES

USE OF ADHESIVE BASED TECHNOLOGIES

USE OF PRECERAMIC POLYMERS AND REACTION BONDED PRECURSORS

EXAMPLES FOR TPS CONCEPTS

CONCLUSIONS AND FURTHER WORK

ACKNOWLEGMENTS

MOTIVATION OF

THE WORK


There is a strong interest in the development of new system concepts (lighter, cost efficient,

more robust) to accessing and return from Space. I.e. new reusable systems, novel ablator

materials, hybrid material concepts, etc…

Those new solutions demands a huge effort, not only in the development of new materials but

also in the integration of them into the subsystems.

Current state-of-the-art protection materials is mainly based on bolted solutions. The

approach is now to keep the bolted solution at the cold structure. The foreseen advantages

are:

Increased reliability of the system against failures, vibrations, etc…

Decrease the complexity of the system: simpler S/O and fixation (bolts not exposed to

plasma)

Cost efficient structures: easy reparability and tile replacement.

Therefore we propose the use of advanced joining technologies as method for integration of

multimaterials on complex thermo-structural shield.

Integration with substrate and subsystems is a big challenge!


The envisaged solutions are based on “in-situ” joining technologies able to create sound

bonding on the different TPS subsystems:

Integration of ceramic matrix composites

Assembly of S/O

High temperature gluing of ablator systems

These technologies are classified according to the different joining processes and the thermal

levels of new system concepts:

Brazing technologies, for the assembly of stand-off and able to withstand temperature

levels up to 1000 ºC

Use of adhesive based technologies (up to 1200 ºC), for the assembly of ablators or

reusable systems.

Use of preceramic polymers and reaction bonded precursors for high and ultrahigh

temperature (above 1500 ºC).

The development and verification approach according to the different envisaged missions is

showed, including physical, mechanical and thermal characterisation addressed to the

envisaged applications, such as capsules for earth re-entry, leading edges for hypersonic

vehicles and so on.

APROACHES USING

BRAZING TECHNOLOGIES


The brazing technology involves the joining of two dissimilar materials substrates by means of

the incorporation of a third material in-between, commonly a metal filler (foil, paste or

powder) which is heat-up above its melting temperature (liquidus)

Special attention must be paid to the CTE mismatch of the whole system. Typically the filler

metal must have an intermediate value between the base materials to be joined.

Also important parameter are wetting and the diffusion of the filler metal to the surface and

the reaction of the filler metal with the substrates.

The temperature limit of this technology is around 900 -1000 ºC, depending on the nature of

the filler metal and substrates.

The envisaged approach is specific for the joining of Ceramic matrix composites with Titanium

parts, particularly in term of the joining of S/Os:

Substrates: CfSiC (SICARBONTM from AIRBUS Group) and Ti6Al4V – Grade 5 (Ti shop)

Metal filler: TICUSILTM (Ag-26.7Cu-4.5Ti, wt.%), paste form from WESGO.

The selected system for the study was:The brazing was carried out in an IPSENVFCK-124

(HV) vacuum furnace. The brazing temperature was 930C and the holding time 10 min.


The joining or flat surfaces showed poor mechanical properties. In order to address the

problem an innovative approach was implemented, which consists in manufacturing a

perforation on the CMC, with two patterns and different parameters;


Joints specially fabricated for the mechanical tests are tested in INSTRON universal testing

machine in which the force was applied at a speed of 1 mm/s to determine the shear strength.

The joint area was 20 x10 mm2.

The determined average shear strength of the CMC was 6.2 MPa (ILSS).

This procedure results in six-fold increase of the shear strength of the joint compared to the

unprocessed CMC


The mechanical shear tests show that failure occurs always within the ceramic material and

not at the joint level.

A fracture mechanism is proposed. More than one CMC interlayers are involved. This is

further confirmed by the fact that the low depth perforations (B1_S, B2_S) do not have an effect

on the shear strength.

Fracture surfaces of perforated CMC/Ti alloy brazed joints

Schematic drawing of the CMC/Ti alloy joint with non-perforated (left) and

perforated CMC (right).

C. Jiménez, K. Mergia, M. Lagos, P. Yialouris, I. Agote, V. Liedtke, at al. Joining of ceramic matrix composites to high temperature ceramics

for thermal protection systems., Journal of the European Ceramic Society 10/2015; 36(3). DOI:10.1016/j.jeurceramsoc.2015.09.038


At the CMC/filler, Ti from the filler metal interacts with the SiC matrix to form carbides and

silicides.


Additional shear test at high temperature have been performed (up to 600 ºC), at AAC at their

tets rig chamber.

The strength is still around six times higher as compared with the baseline solution: 6.97 ±

0.32 MPa vs. 1.00 ± 0.24 MPa

Test Rig Chamber & Set-up

Shear load results: No perforations ( left) and with perforations (right)


Another important issue is the fact that the perforation could guarantee a non catastrophic

failure

Comparation of the results obtained at RT

USE OF ADHESIVE BASED

TECHNOLOGIES

ADHESIVE TECHNOLOGIES

The high temperature adhesive technology involves the application of an inorganic glue

(ceramic particles + silicate binder) between to substrates and its further curing step. The

adhesive withstand the mechanical loads at high temperature due to the pyrolisis of the

binder and the performance of the ceramic fillers.

Usually these technologies are coming from US, while the development in Europe and its

commercially availability is quite limited.

Product Portfolio from AREMCO (US)

The adhesive technology has been employed to glue a low density ablator (ASTERM) onto a ceramic

matrix composites (SICARBON).

6 different adhesives has been envisaged for both hybrid family systems

Pull-off test and wetting tests and microstructural investigation has led to the pre-selection of 3 adhesives:

a) alumina with low viscosity

b) zirconia and zirconia silicate with high viscosity and

c) graphite with low viscosity


Tradename Aremco 670

CeramabondTM

Aremco 569

CeramabondTM

Aremco 835

CeramabondTM

Aremco 685-N

CeramabondTM

Aremco 669

Graphi-BondTM

Co 931

Resbond TM

Major

Constituent Al2O3 Al2O3 ZrO2 - ZrSiO4 ZrO2 - ZrSiO4 Graphite Graphite

Viscosity, cP 2,500 - 5,000 Paste 20,000-40,000 5,000-20,000 20,000 - 40,000 Paste

Temperature

Limit, (°C) 1650 1650 1371 1371 760 2980

CTE,

in/in/oC x 10-6 7.7 7.6 7.2 8.1 7.6 7.38

Performance on

ASTERM© Good Fair Fair Low Good -

Performance on

SICARBON© Good Low Good Low Good -

Pull-off test No material

separation Failed

No material

separation Failed

No material

separation

Partial

failure

Cross section

microstructure Good bonding

Weak bonding

with SICARBON© Good bonding Weak bonding Good bonding

Weak

bonding

Selection Yes No Yes No Yes No

Pre-selection of 3 adhesives:


Low viscosity

High viscosity

High viscosity

Low viscosity High viscosity

Low viscosity

Shear test at NCSRD-Demokritos (Room temperature and LN2)

In the majority of the SICARBON + ASTERM fracture takes place inside ASTERM (similar shear strength of

the ASTERM)

But ultimate shear strain is higher for zirconia and graphite based adhesives.

At LN2 the shear strength, compared to that at RT, increases from 30 % up to 100% because the ablative

material becomes stiffer.


Alumina Zirconia – Zirconia Silicate Graphite

ASTERM

+

SICARBON

Material combination Adhesive

Ult. Shear Strength - USS

(MPa)

Ultimate Shear Strain -

USE (%)

RT LN2 RT LN2

ASTERM© + SICARBON©

Alumina 0.75 ±0.18 - 2.70 ± 0.90 -

Zirconia -

Zirconia Silicate 0.68 ±0.10 0.85 ± 0.08 4.9 ±1.3 5.4 ±3.8

Graphite 0.65 ±0.08 1.30 ± 0.32 3.20 ± 0.60 3.70 ±

0.70

Thermal schock at INCAS

The three adhesives (alumina, zirconia and graphite) characterised under thermal shock

Use of CALCARB (Commercial carbon substrate, similar to ASTERM or PICA preforms), to prevent

damage of the facility.

Samples (30 x 50 x 10 mm3) are heated at a 9.5 ºC/s rate up to 1100 ºC (2 min maintenance).

The temperature is monitored by both a pyrometer and a thermocouple inserted in the joint

Post-test analysis confirms the low performance of the alumina adhesives.


Shear strenght at high temperature (Indutherm)

The material combination is tested at: RT, 150 ºC and 700/900 ºC

ASTERM/SICARBON system fulfil requirements (0.1 MPa) with zirconia at RT, 150 ºC and 700 ºC. With

graphite is very close.


-50

-30

-10

10

30

50

70

90

110

130

150

0,0

100,0

200,0

300,0

400,0

500,0

600,0

700,0

800,0

900,0

1000,0

0 1000 2000 3000 4000 5000 6000

Forc

e [N

]

Tem

pe

ratu

r [°

C]

Timesteps

Sample Interface

Sample Holder

Load cell

Test results at 900 ºC ASTERM/SICARBON sample before and after test at 700 ºC

K. Triantou, K. Mergia, S. Florez, B. Perez, J. Barcena, W. Rotärmel, G. Pinaud, W.P.P. Fischer, Thermo-mechanical performance of an

ablative/ceramic composite hybrid thermal protection structure for re-entry applications, Composites Part B Engineering 12/2015; 82:159-

165. DOI:10.1016/j.compositesb.2015.07.020

PRECERAMIC POLYMERS

AND REACTION BONDED

PRECURSORS

PRECERAMIC POYMERS & REACTION BONDING

When the temperature requirement is quite high (over 1000 ºC) there are two interesting

approaches for the bonding of ceramic substrates, by means of:

Application of preceramic-polymers

Reaction bonded joining

Both methods are derived from techniques from the manufacture of monolithic ceramics and

ceramic matric composites (mainly SiC based)

The use of pre-ceramic polymers involves the application of a polymer which is a precursor of

a ceramic (polysilane, polysiloxane), Further steps are curing and ceramization step (mostly

up to 1600 ºC). Ceramic fillers are added to increase the yield and reduce the shrinkage

Reaction bonded means to “in-situ” obtain the filler from the element precursor. In the case of

SiC from Si and C sources and produce a chemical reaction. Also typically ceramic fillers are

added to increase the yield and reduce the shrinkage.

Both methods have been explored to the joining of CMCs to ceramic lattices (more details are

available at www-thor-project.com)


The study has consisted in the trade-off of the different joining routes for the integration of the

SiC/SiC material to the SiC lattice structure:

Ceramic adhesives

Polysilazane modified by different fillers (preceramic polymers)

Phenolic resin modified by fillers (reaction bonding)

After different optimization loops a selected design of the composition was defined.

Different samples trials were performed to evaluate the mechanical behaviour at high

temperature. Shear strength was selected as the best test for the selection route (at AAC)


Ceramic adhesives showed reduced adhesion with the base materials at RT. Resbond fails

already at 830 ºC

Preceramic polymers based on phenolic and polysilxane modified with filler showed promising

results

Polysiloxane shows 425 +/-72 N at 1,220 °C

Phenolic Resin shows 633 +/-153 N at 1,220 °C

Both polysiloxane and phenolic Resin have residual strength up to 1,520 °C =>

substantial thermal safety margin

From testing, both bonding systems are suitable for application

Testing of Joints at 1,220 °C

EXAMPLES FOR TPS

CONCEPTS

TPS VALIDATION EXAMPLES

Validation of the joining technologies on different TPS concepts and applications through

three FP7 European projects:

PROJECT APPLICATION JONING TECHNOLOGY VALIDATION

SMARTEES REUSABLE FOR EARTH

ATMOSFERIC RE-ENTRY

• BRAZING • PRECERAMICS

TEST RIG

HYDRA SEMI-REUSABLE FOR EARTH ATMOSFERIC

RE-ENTRY

• BRAZING • ADHESIVES

THERMAL SCHOCK VIBRATION RIG PLASMA WIND

TUNNEL

THOR HYPERSONIC

VEHICLES • REACTION

BONDING ARC JET

HYDRA SMARTEES THOR


PROJECT SMARTEES

Definition, selection and implementation of the bonding processes.

External hot-structure to CMC assembly1 -> Temperatures > 1500 ºC

Assembly of stand-offs to the structure2 -> Temperatures < 900 ºC

Multilayer/CMC Joining, Credit:NCRSD/TECNALIA

CMC/Stand-off Joining, Credit:NCRSD/TECNALIA

1. C. Jimenez, M. Lagos, I. Agote, K. Mergia, C. Badini, E. Padovano, C. Wilhelmi and J. Barcena. ““High Temperature Joining Solution For Thermal

Protection Systems Based On Intermetallic Alloys” 37th International Conference and Exposition on Advanced Ceramics and Composites. Daytona

Beach, USA, 27 January – 1 February 2013.

2. X. Hernandez, C. Jiménez, K. Mergia, P. Yialouris, S. Messoloras, V. Liedtke, C. Wilhelmi, J. Barcena, “An Innovative Joint Structure for Brazing

Cf/SiC Composite to Titanium Alloy”. Journal of Materials Engineering and Performance , vol. 23, pp. 3069.3073. ISSN 1059-9495.


PROJECT SMARTEES - CMC SANDWICHES

Preparation of upper skin (high temperature joint)

LC1 50 x 50 mm2 sub-scale

samples

LC2 50 x 50 mm2 sub-scale

samples


PROJECT SMARTEES - STAND-OFF BRAZING

LC1 50 x 50 mm2 sub-scale samples



LC1 50 x 50 mm2 sub-scale samples

BEFORE BRAZING AFTER BRAZING

The joining process does not produce any

cracks in the foam material!!



LC2 150 x 150 mm2 samples


PROJECT SMARTEES –THERMAL TEST

Initial tests

performed in LC1 (target temperature at metallic interface ~600 °C)

and in LC2 (target temperature at metallic interface ~840 °C)

Tests performed under vacuum

30 cycles each

Results:

Neither a mass change nor any visible degradation – apart from the apparent removal of an

oxide layer from manufacturing

LC1 as received LC1 after50 cycles LC2 as received LC2 after 50 cycles

Figure 1: CMC/Ti joints after testing


PROJECT SMARTEES –THERMAL TEST


PROJECT HYDRA

Validation of brazed and glued structures

CMC/Ti BRAZING ABLATOR/CMC ADHESION


PROJECT HYDRA - Infra-red test (Airbus DS SAS)

Use of IR lamps to achieve 0.6 MW/m2

Test duration 60s for graphite and 100s for zirconia adhesive

Temperatures at the Ablator/CMC interface are at the service range of the adhesive: 800 ºC

for graphite and 1300 º C for zirconia.

No apparent and visible damage was observed (debonding or failure)

TCs recording for IR test: Graphite and Zirconia Predicted temperatures


PROJECT HYDRA - Vibration test (HALT Facilities at CTA)

5 200010 100 10006 7 8 9 20 30 40 50 60 70 80 90 200 300 400 500 600 700 800

Decade

Unknown (HERTZ)

1e-3

200

10e-3

100e-3

1.0

10

100

2.0e-3

3.0e-3

5.0e-3

7.0e-3

20e-3

30e-3

50e-3

200e-3

300e-3

500e-3

700e-3

2.0

3.0

5.0

20

30

50

Log

Unknow

n (

(G))

S15001_Z_SL.002 AUX Channel 8 000:04:18 0.000 ACL029 (3)x 29-Jan-2015 13:22:40 Bx

S15001_Z_SL.003 AUX Channel 8 000:04:19 0.000 ACL029 (3)x 29-Jan-2015 13:52:05 Bx

5 200010 100 10006 7 8 9 20 30 40 50 60 70 80 90 200 300 400 500 600 700 800

Decade

Unknown (HERTZ)

1e-3

200

10e-3

100e-3

1.0

10

100

2.0e-3

3.0e-3

5.0e-3

7.0e-3

20e-3

30e-3

50e-3

200e-3

300e-3

500e-3

700e-3

2.0

3.0

5.0

20

30

50

Log

Unknow

n (

(G))

S15001_Y_SL.003 AUX Channel 8 000:04:18 0.000 ACL029 (3)x 29-Jan-2015 16:04:52 Bx

S15001_Y_SL.002 AUX Channel 8 000:04:19 0.000 ACL029 (3)x 29-Jan-2015 15:45:32 Bx

5 200010 100 10006 7 8 9 20 30 40 50 60 70 80 90 200 300 400 500 600 700 800

Decade

Unknown (HERTZ)

1e-3

200

10e-3

100e-3

1.0

10

100

2.0e-3

3.0e-3

5.0e-3

7.0e-3

20e-3

30e-3

50e-3

200e-3

300e-3

500e-3

700e-3

2.0

3.0

5.0

20

30

50

Log

Unknow

n (

(G))

S15001_X_SL.002 AUX Channel 7 000:04:18 0.000 ACL029 (2)z 29-Jan-2015 16:59:00 Bz

S15001_X_SL.003 AUX Channel 7 000:04:19 0.000 ACL029 (2)z 29-Jan-2015 17:15:51 Bz

Launcher specifications

Low sine sweep before and after test

Test configuration Z, Y and X axis


PROJECT HYDRA - Plasma Wind Tunnel Verification (MAIN CAMPAIGN)

The thickness of the ablator is fixed to 10 and 12 mm

Heat flux of 5MW/m2, stagnation pressure of 3710 Pa, time extended to 85 seconds.

Surface temperature is around 3300 K

Temperature at the ablator/CMC interface

up to 1400 ºC were achieve with 10 mm ablator samples

800 ºC in the 12 mm ablator samples

no visible damage at this interface.

Laser Recession Measurements -> up to 8 mm

More details given by G. Herdrich


PROJECT THOR – ASSEMBLY OF SHARP LEADING EDGES

Leading edge thermal management concept based on convective cooling

After curing After pyrolisis


PROJECT THOR – ASSEMBLY OF SHARP LEADING EDGES

Ceramization step & assembly

General comments

Visual inspection shows no cracks

appeared after the cycle.

The lattice structure is well joined

to the CMC material

Arc Jet test details at THOR website (www.thor-project.com)

CONCLUSIONS AND

FURTHER WORK


Different joining methods for thermal protection system have been traded-off

Different solutions are envisaged depending on the specific mission and application and the

corresponding temperature levels:

Brazing technologies, for the assembly of stand-off and able to withstand temperature

levels up to 1000 ºC

Use of adhesive based technologies (up to 1200 ºC), for the assembly of ablators or

reusable systems.

Use of preceramic polymers and reaction bonded precursors for high and ultrahigh

temperature (above 1500 ºC).

A basic manufacturing study of these three systems have been carried out to determine the

process feasibility basic mechanical properties, heatflux and temperature limits.

A second step have been carried out to verify and qualify the solutions in representative

system re-entry conditions.

Further studies and developments are required to increase the TRL and implement the

solutions in real flight conditions

ACKNOWLEDMENTS

European Space Agency (M. Bottacini and B. Jeusset )

European Commission

Research Executive Agency (C. Ampatzis, T. Branza, P. Mota-Alves)

Airbus Safran Launchers GmbH (W. Fischer)

Airbus Safran Launchers SAS (J.M. Bouilly, G. Pinaud)

EADS-Innovation Works (C. Wilhelmi, F. Meistring).

NCSRD (S. Messoloras, K. Mergia , P. Yialouris, K. Triantou).

ERBICOL SA (D. Gaia and S. Gianela)

Aerospace and Advanced Composites GmbH (V. Liedtke)

SUPSI (M. Barbato, C. D’Angelo and A. Ortona)

Politecnico di Torino (E. Padovano and C. Badini)

Tecnalia (C. Guraya, X. Hernandez, C. Jimenez, M. Lagos, I. Agote, B. Perez, S. Florez, I. Iparraguirre)

HPK Liéges (A. de Montbrun, M. Descomps)

DLR (B. Esser, A. Gülhan, H. Hald, C. Zuber, W. Rotaermel)

HPS (P. Portela)

INCAS (G. Ionscu, C. Band and A. Stefan)

ICMCB (D. Bernard and V. Leroy)

IRS (G. Herdrich, B. Massuti, R. Wernitz)

Tübitak (A. Okan)

JAXA (H. Tanno)

FGE (J. Merrifield and L. Haynes)

Thales Alenia Space (D. Francesconi, M. Portaluppi)

The research leading to these results has received funding from the European Union Seventh

Framework Programme (FP7/2007-2013) under grant agreement n° 262749, 283797, 312807

ACKNOWLEDMENTS

MANY THANKS FOR YOUR

ATTENTION!

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