Piece made of alloy a high temperature, which places a protective coating prior to

摘要

It forms a coating resistant to the environment, punctual, on a localized surface of a piece of working at high temperature, by applying to this surface a layer of at least one element selected from pt and rh, pd, pt, in a thickness of 0,0002 thumb at least of 0,0006 thumb and to a distribution the mean of at least 0,07 grams per square inch. The mixture is heated, the layer to 1800 deg.f to 2050 deg.f during one half-wave - hour at approximately 4 hours in order to diffuse the element in the surface. It is then aluminide the layer to obtain a total thickness of coating of 0,001 thumb to 0,005 thumb. The part thus obtained has an additional coating resistant to the environment. The coating comprises an external portion containing at least 17% by weight of the element selected and a aluminide of the substrate, and an inner part which is a diffusion zone between the outer part and the surface. According to one embodiment, the external portion comprises two phases, a first phase consists of a aluminide of the element selected which is present at a content of at least 40% by weight, and a second phase, mixed with the first, which comprises a aluminide, the al content is at least 20% by weight.