S. Ali Moeini, Hannes Greve and F. Patrick McCluskey
CALCE/Department of Mechanical Engineering, Clark School of Engineering, University of Maryland, College Park, Maryland 20742
Low-temperature transient liquid phase sintering (LT-TLPS) can be used to form high-temperature joints between metallic interfaces at low process temperatures. In this paper, we will describe the processing and shear strength, along with the shock fatigue resistance of sintered joints made by this process. Joints made from different ratios of Ni and Cu high melting temperature constituents paired with Sn-based low melting temperature constituents have been evaluated. For the shear studies, the softening behavior of test samples joined by Ni-Sn3.5Ag and (Ni,Cu)-Sn3.5Ag sinter pastes have been assessed using a fixture designed for high temperature shear testing up to 600 oC. The reliability of sinter paste joints in drop-shock environments will be discussed. It is shown that joints formed from these sinter pastes possess improved drop-shock reliability compared to Sn3.5Ag solder joints and melting temperatures considerably higher than those of conventional high temperature solders (e.g. Pb5.0Sn2.5Ag).
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