HEAT-RESISTANCE AND PHASE-COMPOSITION OF TI-SI COATINGS ON NIOBIUM

A diffusion silicide coatings on refractory under thermal shock, A pro spective method of improving their durability is the formation of mult i-component coatings, Ti is one of the widespread components of such c oatings. In this work, process of simultaneous diffusion saturation of niobium by Ti and Si in powder mixtures has been investigated, The co atings can be divided into two basic types: Nb-TI solid solutions and Nb and Ti silicides, The coatings of the first type obtained in Ti-Ti5 Si3 powder mixtures. The complex silicide layers were observed in the packs with higher silicon activity (Ti5Si3-TiSi and TiSi2-TiSi mixture s). The activities of Ti and Si have been shown to be principal contro lling factores in coating phase in composition. The coatings allows to increase heat-resistance of the niobium and niobium alloys up to 2000 degrees C (1,5 hour).