The optimal parameters of plasma spraying which provide protective coatings of high quality and acceptable durability were founded. Thus the replacement of the hazardous technology was done successfully. The obtained results prove that the proposed mathematical models are adequate and precise, therefore it possible to use it for studying interactions between various factors including process parameters and quality parameters of coating. The practical results of investigations were implemented in some Latvian enterprise specialized in manufacturing of different kinds of components for the heavy load hoisting and other equipment