Plasma spray forming of free standing W-Al functionally graded materials

The aim of this study is to perform free standing materials which density varies continuously from 2,2 to 17,3 g/cm(3) through a total thickness of 4,5 mm. In order to reach material optimal performances, it is necessary to determine specific mixture laws taking into account the combination of the different materials in a same plasma jet. A relationship integrating the deposition efficiency, the powder feed-rate, the density of the single sprayed materials, has been established to predict the result of the combination in terms of density, thickness and deposition efficiency. The good agreement of the mixture laws with the experiments allows to build up coatings with a parabolic density profile keeping layer thickness constant.