Preparation and Properties of Anti-oxidation Coatings of Molybdenum-Tungsten Alloy

High temperature oxidation resistant coatings were prepared through nitriding and siliconizing the surface of Mo-W alloys with different tungsten contents by in-situ reaction method. The influence of W content on the morphology and microstructure of the coating was analyzed by scanning electron microscope and X-ray diffraction. The oxidation resistance properties were also evaluated. In addition, the mechanism of anti-oxidation was researched. The results indicate that the amount of silicon seepage on the coating surface decreases with increasing the W content in Mo-W alloy, which reveals that the increase of W content can slow down the outward diffusion of Si element effectively. Furthermore, the high temperature oxidation experiment at 1600 degrees C proves that the Mo-30wt%W surface coating has the best oxidation resistance, and the anti-oxidation time is up to 327 h. As a result, the increase of tungsten content improves the oxidation resistance of the coating to a certain extent.