Dear Friends,
Have a look on attached photographs of Chrome Oxide coating done with Plasma Spray System (F- 4 Gun).
1) The color of the coating is not uniform. some areas it is light greenish and in other areas it is dark greenish. Can any body tell why it is happening?
2) By visual inspection, it seems to be there is no proper bonding of layers.
The process parameters used to coat chrome oxide given below:
Current : 500 Amps, Agron Gas --- 38 NLPM, Hydrogen --- 12 NLPM, Carrrier gas Argon --- 2.6 LPM, Disc RPM is 30%
The above phenomena observed in 87Al2O3 +13 TiO2 and 97Al2O3 + 3Al2O3 coating also.
I Request Mr. Gordon to share is experience to solve this issue.
Regards,
SREENIVAS