Metco 136 F coatings

[raviswanadha]

Hi gordon
we are spraying metco 136f with plasma 9MB system and wanted to know its characteristics in comparision with metco 6p type flame sprayed 136f coatings.
1. in Density.
2. porosity.
3. overall coating performance.
4. wear resistance properties.
regards

[Gordon]

Hi Raviswanadha

The 6P - 136F coatings are surprisingly good when compared to plasma 136F coatings and other 6P ceramic coatings. Plasma coatings will though show slightly better overall coating qualities (density, hardness, bond strength and finishing capability, wear resistance), apart from possibly thickness limitation. The differences though appear relatively small compared to many other 6P vs plasma coatings.

Choice between them will come down to part application/function and economics. If you want the best, go for plasma. Many applications where 6P 136F coatings have performed well in the past, may not show significant benefit by moving to plasma coatings.

[raviswanadha]

thank you Mr. Gordon, is it due to the presence of Silica in 136F which might decompose at higher temperature.
regards.

Hi Raviswanadha

The 6P - 136F coatings are surprisingly good when compared to plasma 136F coatings and other 6P ceramic coatings. Plasma coatings will though show slightly better overall coating qualities (density, hardness, bond strength and finishing capability, wear resistance), apart from possibly thickness limitation. The differences though appear relatively small compared to many other 6P vs plasma coatings.

Choice between them will come down to part application/function and economics. If you want the best, go for plasma. Many applications where 6P 136F coatings have performed well in the past, may not show significant benefit by moving to plasma coatings.

[Gordon]

Hi Raviswanadha

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.).