High Thermal Conductivity Plasma Sprayed AlN Coating

Among non-oxide ceramics, aluminum nitride (AlN) has attracted wide attention in a diverse range of applications due to its considerable attractive properties such as high thermal conductivity and chemical stability. Thermal spraying is a versatile technique to deposit abradable and protective thick ceramic coatings. However, it was impossible to fabricate AlN coatings by conventional thermal spray processes directly from AlN feedstock powder due to thermal decomposition of AlN during spraying. In the last decade we were apple to fabricate various AlN coatings through the reactive plasma spraying of several materials (Al, Al/AlN, Al/NH₄Cl, Al₂O₃, Al₂O₃/AlN) in atmospheric ambient. This study describes the way to fabricate very high thermal conductivity plasma sprayed AlN coatings. Furthermore, the influence of feedstock powder material and several process parameters were also investigated.

It was possible to fabricate very high thermal conductivity atmospheric plasma sprayed AlN coatings up to 175 W/m.K.