Spinel powders for plasma spraying were fabricated for application as prote
ctive coatings against chemical attack from fused metal or glass. Due to th
e complex structure of spinels, the process of fabrication of the powder ne
eded several steps to get rounded, well-crystallized grains. This consisted
of spray-drying, sintering in an electrical furnace and then melting in an
induction plasma. Several compositions were made and powders were then pla
sma sprayed on steels. Following the initial compostion, preferential volat
ilization was observed due to the successive thermal treatments, leading to
coatings having compositions different from the powder. The microstructure
and homogeneity of the coatings was also studied using scanning electron m
icroscopy. (C) 1998 Elsevier Science Limited. All rights reserved.