Artemenko

This work presents results of thermodynamic studies and searching for a rational chemical activation dopant for deposition of tantalum from the gaseous phase onto surfaces of parts of gas-turbine engines made of heatproof nickel alloys in order to increase the diffusion stability of heatproof aluminide coatings. Calculations showed a possibility of using nickel dichloride for tantalum and tantalum-chromium coating of nickel alloys. During this investigation several restrictions on the number of additional alloying elements in the saturating mixture were discovered. An effective amount of chromium for the combined process of tantalum-chromium coating was also determined.

This work presents results of thermodynamic studies and searching for a rational chemical activation dopant for deposition of hafnium from the gaseous phase onto the surface of gas-turbine engine’s parts made of heatproof nickel alloys in order to increase diffusion stability of heatproof aluminide coatings. Calculations showed impossibility of using a traditional activation dopant, that is nickel dichloride, for hafnium coating because liberation of gaseous hafnium compounds occurs at temperatures which are beyond reach for modern equipment for thermochemical treatment. During this investigation it was established that ammonium chloride could be used as an activation dopant. If hafnium consists one fifth of ammonium chloride in the saturating mixture, amount of gaseous hafnium chloride reaches its maximum.