Properties of Al sub(2)O sub(3) and NiAlSi coatings obtained by atmospheric plasma spraying on 34CrNiMo sub(6) substrate

In military and mining industry are many machine elements which are subjected to thermal and structural analyses. Idlers must have a high wear resistance, because the functionality of the entire transmissions systems depends on them. Since the maintenance costs of the machines are very high, here we propose to improve the performances of the machine elements and also improve the physical, mechanical and chemical proprieties of those elements super(1). We have chosen the steel type 34CrNiMo sub(6), MoCN class, STAS 691-880 as basic material and coated it with NiAlSi and Al sub(2)O sub(3) powders. The prepared samples are analyzed by XRD, EDS and SEM. The NiAlSi and Al sub(2)O sub(3) coating deposited on steel substrate, is dense, but on SEM analysis we discovered that it has some fine cracks on NiAlSi deposition, and good elasticity of the layer, but also we could consider that the layer has no cracks because of the good deposition process has resulted for Al sub(2)O sub(3). The deposition process should have been made by heating the substrate, to expand, in order to return to original shape simultaneously to the NiAlSi and AL sub(2)O sub(3) molten particles solidification.