FEATURES OF THE VACUUM ACTIVATED THERMO-CHEMICAL TREATMENT OF MATERIALS

In this study the option of a heat-resistant layer is approved for protecting products from niobium was tested and based on silicides of molybdenum and niobium. Coating was formed by method of vacuum diffusion saturation in presence vapors of sodium chloride. As the saturating environment was used mixture, consisting of powders disilicide of molybdenum, silicon and alloying additions. The thermodynamics calculation of possible chemical reactions was executed for determination of components saturation environment of gas and terms transfer of molybdenum in niobium. Niobium samples were siliconized at the temperature of. = 1250 degrees C within 7 hours and stream activator 1 g/hour. The coating consisted of two layers, thickness upper layer - 90 mkm, adjoining to basis - 10 mkm. Also the process of vacuum-activated boriding of steel 45 was investigated.