Am. Alfantazi et U. Erb, MICROHARDNESS AND THERMAL-STABILITY OF PULSE-PLATED ZN-NI ALLOY COATINGS, Materials science & engineering. A, Structural materials: properties, microstructure and processing, 212(1), 1996, pp. 123-129
The microhardness and thermal stability of Zn-Ni alloy coatings with N
i content up to 62 wt.% produced by the square wave pulse-plating tech
nique were investigated. The microhardness of these coatings was obser
ved to increase with increasing Ni content. Several factors which cont
ribute to the hardness such as solid solution hardening, effects owing
to different phases and grain size were discussed in order to explain
the hardness behaviour. Two methods, namely conventional furnace anne
aling and in-situ annealing in a transmission electron microscope were
considered in this work to study the thermal stability of Zn-14 wt.%
Ni and Zn-55 wt.% Ni alloys, respectively. The results indicated that
microcrystalline Zn-14wt.% Ni alloy coatings were thermally stable up
to a temperature of 200 degrees C for 24 h, however electron beam expo
sure of a nanocrystalline Zn-55 wt.% Ni alloy deposit for a few minute
s in the transmission electron microscope resulted in considerable gra
in growth.