Hi Raviswanadha
Quote:is it due to the presence of Silica in 136F which might decompose at higher temperature
I don't think there is any problem with decomposition of silica with normal spraying parameters. The addition of silica helps toughen and seems to make coatings more wear resistant compared to pure chromium oxide coatings (of similar powder particle size). The silica content may certainly be the reason the 136F flame spray coatings are good say compared to pure chromium oxide and other ceramics, possibly due to a fluxing type effect (better wetting, lower melting point etc.).