O21-High temperature lead-free solder:Phase relations in...

High temperature leadHigh temperature lead--free solder:free solder:

Phase relations in (Phase relations in (Cu,NiCu,Ni))--SnSn--ZnZn

R. Divakar, C. Schmetterer, H. Flandorfer, H. IpserR. Divakar, C. Schmetterer, H. Flandorfer, H. Ipser

University of Vienna

Department of Inorganic Chemistry / Materials Chemistry

TOFA 2010 Porto, Portuguese September 12-17, 2010

ContentContent

� Introduction and Bibliography

� The binary systems

• Cu-Sn

• Ni-Zn • Ni-Zn

� Our results on Ni-Sn-Zn

• Isothermal sections at 700, 800 and 900 °C

• Ternary phases

� Summary and Outlook


°C

1000

800

600

Hard S

oldering

Silver Solders

Copper-Gold-AlloysTraditionalTraditional

SoldersSolders

°C

1000

800

600

Hard S

oldering

Silver Solders


SoldersSoldersH

ard Soldering

Silver Solders


SoldersSolders

400

200

Soft S

olderingH

ard Soldering

Tin-Lead Alloys

Bismuth Alloys

Cadmium-Zinc Solders

IndiumAlloys

Lead-Silver Alloys400

200

Soft S

olderingH

ard Soldering

Tin-Lead Alloys

Bismuth Alloys


IndiumAlloys

Lead-Silver Alloys

Soft S

olderingH

ard Soldering

Tin-Lead Alloys

Bismuth Alloys


IndiumAlloys

Lead-Silver Alloys


Lead-free Solder materialsfor low temperature soft soldering are well establi shed:

� Ag-Sn (e.g., Sn-3.5Ag), Cu-Sn (e.g., Sn-0.7Cu)� Ag-Cu-Sn („SAC“, e.g.: Sn-3.7Ag-0.7Cu)� In-Sn (e.g., Sn-52In), Ag-In-Sn (e.g., Sn-2.8Ag-20In)� Bi-Sn(e.g.: Sn-58Bi)� Sn-Zn-X, where X = Cu, Ni, Ag, etc…


Lead-free Solder materialswith T m ≥≥≥≥ 230°°°°C up to 350 °C are necessary for:

� power circuits with very high levels of conductivity required� automotive industry under bonnet applications - high

current and low voltage, high temperatures within the engine area

� step soldering approach ⇒ soldering of various levels of the package with different solders of different melting points

COST Action MP0602

Advanced Solder Materials for High Temperature Application (HISOLD)

Their nature, design, process and control in a mult i-scale domain


Project leaders: Ales Kroupa and Andy Watson

~ 50 Scientist of 17 countries, 2007 - 2011

The constituent binariesThe constituent binaries

Also PD’s of well established binary systems of high technological importance can be improved!

We should not trust blindly in compilations and ass essments!

• Cu-Sn ⇒ very well established, but almost no experimental investigation since 1950ties! Unclear situation at the Cu-rich side concerningsince 1950ties! Unclear situation at the Cu-rich side concerning

ββββ (W-type) ↔↔↔↔ γγγγ (BiF 3-type) transformation

• Ni-Sn ⇒ new investigation by Schmetterer et al., published 2007

• Cu-Zn ⇒ new investigation ⇒ first results

• Ni-Zn ⇒ new investigation ⇒ preliminary results

• Sn-Zn ⇒ simple eutectic systems


Literature informationLiterature information

Some information to the phase relations in the ternary Cu-Sn-Zn is available, literature data to Ni-Sn-Zn are very scarce:

Cu-Sn-Zn

• Several vertical sections, 2 isotherms, liquidus projection mainly based on early investigations from 1913-1937.

• Thermodynamic assessment: T. Jantzen and P.J. Spencer, 1998• Further information to the Cu/Zn corner: C. Vilarinho et al., 2004• Phase equilibria: C.-Y. Chou et al., 2006• Liquidus projection and modeling: Y.-C. Huang et al., 2009

Ni-Sn-Zn

• Little information to the Sn-Zn rich side: A. Mayer et al., 1968• Phase equilibria (isotherms at 200, 500, 800 °C): J. Chang et al; 2010


The The binarybinary CuCu--ZnZn phasephase diagramdiagram

Cu-Zn PD from Massalski‘s compilation based on the assessment of experimental data byG.V. Raynor, 1944

• Extended solid solubility of Zn in Cu, small amount of Cu in Zn.• 5 IMC’s: β, δ (W-type), β’ (CsCl-type), γ (γ-brass type) and ε (Mg-type).• Ordering phases in the (Cu) solid solution (S. Müller and A. Zunger, 2001).


• 5 samples have been prepared!• Annealed at various temperatures

650, 580, 490, and 400 °C• XRD, EPMA, DTA

The binary NiThe binary Ni--Zn phase diagramZn phase diagram

Ni-Zn PD from Massalski‘scompilation based on the assessmentof experimental data byP. Nash and Y.Y. Pan, 1987

• Extended solid solubility of Zn in Ni, no significant amount of Ni in Zn.• 4 IMC’s: β (CsCl-type), β1 (AuCu-type), γ (γ-brass type) and δ (CoZn13-type).• Metastable phase formation at Ni-rich side (e.g. Murakami et al., 1984).


• First 4, finally 17 samples at all!• Annealed at various temperatures

900, 800, 700, 600, and 400 °C• XRD, EPMA, DTA

The The binarybinary NiNi--ZnZn phasephase diagramdiagram

• Ni-rich samples quenched from 900 and 800 °C ⇒ β1, (Ni) and up to 3 further phases: bcc Ph. (a=5.0431), “Ni3Zn” (AuCu3-type), trig. Ph. at. ~ 37 at.% Zn (LaF3-type?).

• long period shear structures Q at the Ni-rich part of the homogeneous range of γ-phase (γ-brass type) described by A.J. Morton (1974) and Nover and Schuster (1980) have been confirmed!


IsothermalIsothermal sectionsection

ofof NiNi--SnSn--ZnZn

700 700 °° CC700 700 °° CC

• Extended ternary solid solubility of β and β1 towards Ni-Sn.• Pronounced ternary solid solubilities of Ni3Zn14, Ni3Sn2-HT and Ni3Sn-LT.• Two ternary compounds, T2 and T3.




800 800 °° CC

• Extended ternary solid solubility of β and β1 towards Ni-Sn.• Pronounced ternary solid solubilities of Ni3Zn14, Ni3Sn2-HT and Ni3Sn-LT.• Stabilization of Ni3Sn-HT (BiF3-type) by additions of Zn.• At least one ternary compound, T2.


800 800 °° CC



900 900 °° CC

• Extended ternary solid solubility of β towards Ni-Sn.• Pronounced ternary solid solubilities in Ni3Sn2-HT and Ni3Sn-LT.• Stabilization of Ni3Sn-HT (BiF3-type) by additions of Zn.


900 900 °° CC

ττττ2 Ni5Sn4Zn

• Single Crystal XRD

• oC40, a = 4.147 Å, b = 12.582 Å,c = 11.642 Å, SG = Cmcm

• Results sent to ICSD,• Results sent to ICSD,CSD No. 421611

• Analogies to NiAs-type (Ni3Sn2), but not a direct superstructure!

• Isotypic structure Ni5Ga3Ge2 described by Bhargava and Schubert, 1974


ττττ3 Ni2Sn2Zn

• Single Crystal XRD• cP40, a = 8.843 Å, SG = Pm-3m

• full occupation in the same cell not possible! Either Sn (40 %) or Zn (60 %), randomly distributed.

• Results sent to ICSD,CSD No. 422044

• Analogies to γ-brass type and Ru3Sn7-type structure

• Very similar structure described as Sn8.7(Ni0.5,Zn0.4,Cu0.1)10.4 by Larsson et al., 1994


Summary and OutlookSummary and Outlook

• A new investigation of Ni-Zn applying various experimental techniques indicates ordering phases in α-(Ni) solid solution and the occurrence of an additional compound at ~ 37 at.% Zn with LaF3 –structure.

• Three isothermal sections of Ni-Sn-Zn at 700, 800, and 900 °C have been established based on available literature data and comprehensive experimental work.

• Two new ternary compounds could be found and their crystal structure • Two new ternary compounds could be found and their crystal structure solved.

• Isothermal sections at 1000 and 1100 °C are under construction.• A liquidus surface projection and various vertical sections will follow.• The binary systems Ni-Zn and Cu-Zn are under investigation. The new

experimental results promise a improved description of the phase relations.

• Cu-Sn-Zn is as well under investigation.


AcknowledgementsAcknowledgements

Many thanks to:Many thanks to:

• All my colleagues of our department for the excellent collaboration

• The FWF for financing the projects No. P-21507-N19• The FWF for financing the projects No. P-21507-N19

• All the co-operation partner within our COST-Action MP0602

• The organizers of this meeting


Thank You for Your attention!Thank You for Your attention!Thank You for Your attention!Thank You for Your attention!


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