Phase Equilibria in Ni-P-SnPhase Equilibria in Ni-P-SnC. Schmetterer, J. Vizdal, H. Flandorfer

and H. Ipser

Department of Inorganic Chemistry – Materials Chemistry

University of Vienna

COST 531 Final Meeting, Vienna, May 2007

Technological BackgroundTechnological Background

Ni(P) layers as a contact material:

Protective Ni-layer on Cu substrate

in fact: amorphous Ni(P) layers; P is impurity!

Interaction with Sn-based solders?basic information from phase diagram

ternary phase diagram - and parts of the binaries! - have not yet been investigated

A ssessed N i-Sn phase diagram.

P. Nash and A. Nash, Bull. Alloy Phase Diagrams, 6 (4) (1985) p. 350-358

Ni-Sn Phase Diagram

Binary ConstituentsBinary Constituents

C. Schmetterer et al., accepted for publication in Intermetallics

Ni-Sn DetailsNi-Sn Details

NiNi33Sn phase transitionSn phase transition NiNi33SnSn22 phase transition phase transition

Ni-P and P-SnNi-P and P-Sn

• both systems are currently under investigation• experimental + CALPHAD

A ssessed N i-P phase diagram. Sn-P phase diagram.

• from powders of binary end members (e.g. Ni3Sn) and red P, and Sn

many problems!- embrittlement of quartz capsules- explosion of capsules • samples contained in alumina crucibles

• alloyed in evacuated quartz tubes employing very slow heating, especially at P > 40 at.%

• annealed at 200, 550, 700,850 and 1050 °C

Sample PreparationSample Preparation

Ni2P

Ni3SnNi3Sn2

InvestigationsInvestigationsIn Vienna:

• DTA – not yet fully interpreted

• XRD – isothermal sections

Short Term Scientific MissionShort Term Scientific Missionhost: A. Kodentsov, TUehost: A. Kodentsov, TUe

• Light microscopy + polarized light

• SEM / EDS

• diffusion couples

Phase relations at 550 °CPhase relations at 550 °C

Pseudo-binarySystem Ni2P – Sn?

Ternary phases: Ni2PSn Ni10P3Sn Ni10P3Sn5

Ni10P3Sn8

T4 – new phase?

Phase relations at 700 °CPhase relations at 700 °C

Phase relations at 850 °CPhase relations at 850 °C

Diffusion CouplesDiffusion Couples

Diffusion CouplesDiffusion CouplesNi3Sn / Ni2P

Annealed at 700 °C in vacuum for 100 h

Ni3SnNi3Sn

Ni3 S

n2

Ni3Sn2

??

Ni12P5Ni12P5

Ni2PNi2P

100 µm

Diffusion CouplesDiffusion CouplesSn / Ni2P

Annealed at 200 °C in vacuum for 4 months

SnNi2P

Ni2PSn

Conclusion and OutlookConclusion and OutlookNi-P-Sn:

• first information on phase equilibria

• diffusion couples

Planned investigations:

• continue the phase diagram study

• Calorimetry – enthalpy of mixing, enthalpy of formation

CALPHAD study of the system

AcknowledgementsAcknowledgements

K. Richter, U. Saeed

A. Kodentsov (TU Eindhoven, NL)

H. Schmidt (Dep. f. Physical Chemistry)P. Roussel (Ecole Nationale Superieure de Lille)A. Leineweber (MPI Stuttgart)

Thanks to:

FWF P-16495-N11, COST 531, ELFNET

Thank You for Your Attention