Monitoring transient liquid phase sintering of Cu-Sn alloys by thermal analysis

Thermal analysis of Cu-Sn powder mixtures has revealed that little interdiffusion occurs in the solid state prior to melting. Quantitative differential scanning calorimetry reveals that the transient liquid phase sintering process is dominated not by the amount of liquid formed, but by the time the liquid is present in the compact. The use of fine Cu powder promotes rapid conversion of the Sn-rich liquid into solid intermetallics; solidification and the development of a transient liquid phase effect. For mixtures using coarse Cu powders, the solidification kinetics are slow and the liquid phase persists. The kinetics of the interaction between Cu and Sn are influenced strongly by the use of a fluxing agent.