Microstructure of Electrodeposited Co-W Alloy Films

Abstract

The structures of Co W binary alloy films electrodeposited at different bath concentrations and different electrodeposition conditions have been studied in detail by means of XRD and HRTEM. The crystallization sequences of deposited films under the heat treatment were examined by XRD. The structures of Co W deposited films were also compared with the Co W thermal equilibrium phase diagram. The results indicated that the structures of Co W deposited films gradually change from crystalline to amorphous phase with increasing W content in the deposited films. The deposited film exists as crystalline when the W if below 24.8 at, whereas it exists as a homogenous amorphous phase when the W is from 25.4 at to 26.0 at. Accordingly, the composition of boundary between the crystalline and homogenous amorphous states can be determined at about 25.1 atW.

Establishing relationships between bath chemistry, electrodeposition and microstructure of Co–W alloy coatings produced from a gluconate bath

“…Claims for the existence of this intermetallic in electrodeposits containing 20.3 at.% W have been made by Tsyntsaru et al [39] but XRD work by Itoh et al [40] supports our findings on Co-W electrodeposits. They have demonstrated a change from crystalline to amorphous deposits above 21.4 at.% W with no evidence of Co 3 W formation.…”

“…low W in the crystalline phase and high W in the amorphous regions. The presence of the crystalline phase in such a mixture has been shown by Itoh et al [40] to encourage further growth at the expense of the amorphous phase during heat treatment in the temperature range 200-500 • C. Transformation from amorphous to the intermetallic, Co 3 W, only takes place a temperatures >600 • C [7,40].…”

Structure Control Theory of Plated Film —Part of Surface Morphology—

“…, Cd 11) , Co 12) , Cr 13) , Cu 14) , Fe 15) , Ni 16,17) , Pt 18) , Ru 19) , Sn 20,21) , Zn 22) )，そして 26 種類の二元合金(Ag Co 23,24) , Al Mn 25 27) , Ag Cu 28) , Au Ni 29) , Au Pd 30,31) , Au Sn 32) , Co Cu 33,34) , Co Fe 35) , Co Ni 36) , Co S 37) , Co W 38) , Cu Ni 39) , Cu Pb 40) , Cu Sn 41) , Fe Mo 42) , Co Mo 42) , Ni Mo 42) , Fe Ni 43,44) , Fe W 45) , Fe Zn 46) , In Sn 47) , Ni B 48 50) , Ni P 51 53) , Ni S 54) , Ni Sn 55 58) , Ni W 59 …”