Advanced VPS/LPPS System Design to Get High Quality and Cost Effective MCrAlY Coatings

In the field of gas turbine and aeronautic engines, MCrAlY coatings are applied on the hot part components (such as blades and vanes) as overlay or bond coat for Thermal Barrier Coatings in order to increase the resistance of the components to high temperature corrosion and oxidation.

Usually, the specifications of the main OEMs (original equipment manufacturers) require the deposition of MCrAlY alloys by low pressure plasma spray (LPPS) or vacuum plasma spray (VPS). Nevertheless, due to the high investment and operational cost of these two techniques development is addressed to find cheaper alternative solution for the deposition of MCrALY and in particular other methods such as air plasma spray (APS) and high velocity oxygen fuel (HVOF) may be desirable for their lower cost.

This paper presents a new generation of LPPS, these machines are a development of the state of the art machine. In particular high degree of automation, simplicity in the machine, low investment cost, high degree of savings in operational and maintenance cost make these machine able to overcame the prejudices grown around these technologies in the last here.

The approach developed and presented in this paper could be applied both to oldest LPPS machine for revamping and upgrade to the state of art and also to the construction of new LPPS machines. In particular some industrial cases are presented in order to highlight the coating characteristics and the process operation procedures.