The paper describes the major features of a recently developed high voltage – low current air plasma spray (APS) process and torch that is based on combined wall and gas stabilizations of plasma (C+Plasma). It is shown that the C+Plasma process is capable of efficiently generating stable plasmas without drifting or pulsing. Plasma gas selection includes N 2 , N 2 -H 2 , N 2 -Ar-H 2 , Ar-H 2 (He), etc. Availability of stable N 2 -H 2 plasmas having enthalpies within 30-70 kJ/sl range offers a new level of APS efficiency and coating quality. The paper includes illustrations of the C+Plasma durability, stability and expanded operating window. The process capability is also illustrated by properties of the advanced MCrAlY bond coatings and dense segmented TBCs (thermal barrier coating).

A recently developed air plasma spray (APS) process and a torch based on the combined wall and gas stabilizations of plasma (C+Plasma) has demonstrated extremely wide operating window and capability to efficiently generate both argon and nitrogen based plasmas including high enthalpy N 2 - H 2 ones. The present paper aims to describe new areas of the extended C+Plasma operating window, in which a significant increase in the APS sprayed coating quality and process efficiency should be expected. The paper includes a brief analysis of properties of different plasmas as well as specifics of coating formation. Analysis showed that with the high enthalpy N 2 -H 2 plasmas a significantly higher heat transfer potential and higher flexibility in controlling the particle acceleration can be achieved than with the argon based plasmas. Consequently, C+Plasma can enable better treatment of sprayed particles, which results in better deposit efficiency and improved coating properties.