Phase evolutions and growth kinetics in the Co–Sn system

Abstract

Co/Sn diffusion couples are annealed at 175-220 °C. The reaction phase CoSn 3 is found to have a narrow homogeneity range of 2 at% with composition 74-76 at% Sn. The growth of this phase is found to be reaction-controlled initially followed by diffusion-controlled later. The marker experiment indicates that Sn is the faster diffusing element in this phase. The CoSn 2 phase is found to grow in the Co/CoSn 3 incremental couples at 200-220 °C.

Phase growth in alpha brass with thin layer of electroplated zinc during homogenization annealing

“…It is well known that for constant temperature, phase growth (ω) maintains the parabolic relationship with time (t) as ω 2 = 2Kt, where K is the coefficient of phase growth [8,9]. The determination of K is carried out by the use of linear regression analysis of ω 2 and t data.…”

Transient Liquid Phase Bonding with Sn-Ag-Co Composite Solder for High-Temperature Applications

“…Previous studies [38][39][40] have identified that at low temperatures below 300 °C, the first forming phase in Sn and Co reactions is CoSn3. However, referring to the Sn-Co phase equilibrium diagram [41,42], it is evident that the melting point of CoSn3, at 345 °C, is insufficiently high for our purposes. At 280 °C, the homologous temperature (T/Tm) for CoSn3 is approximately 0.9, indicating its incapability to withstand the high-temperature demands of power device junctions.…”