Sintering of c-BC2N particles, solid solutions of metallic phases with additives of oxide components and NiCr at ultrahigh load and temperature of plasma spark sintering, high compression pressure during the explosive method

Abstract

   The article shows the effect of ultra-high pressing loading 1,65 GPа at 1800 °C during spark plasma sintering, pressure compaction 2,30 GPa at 1260 °C during explosion sintering of the particles of solid solutions of ceramic and metallic phases with the additive of the mixture of oxide powders, NiCr on the phase composition, microstructure, grains sizes of crystalline phases, relative density, linear shrinkage, microstructural features of boundary layers, paths of microcracks, physical-mechanical properties of mullite‒c-ZrO₂‒c-BC₂N‒NiCr‒V‒Mo‒Zr‒W, mullite‒c-ZrO₂‒c-BC₂N‒NiCr‒Cr‒Mo‒Nb‒Ta samples. Synthesized powders of h-BN and NiCr are characterisized by different intensity of crystalli-zation of h-BN and NiCr phases, respectively. Sintered by spark plasma method c-ZrO₂ at pressing loading 35 MPa and 1400 °C, g-BC₂N at pressing loading 60 MPa and 950 oC show evoluted crystallization of c-ZrO₂ and g-BC2N phases, respectively, crystalline, uniform, dense micro-structures. Sintered at ultra-high pressing loading 1,65 GPa by spark plasma method samples show evoluted mullitization, crystallization of c-ZrO₂, c-BC₂N, NiCr, β-V,Mo,W,Zr, β-Cr,Mo,Nb,Ta phases, more crystalline, uniform and densely sintered microstructures, variously dispersed grains of crystalline phases at 1800 °C unlike the samples, obtained by the explosion sintering. Sintered by two methods samples are differ by the density, uniformity, width, path of boundary layers and propagating microcracks across these boundary layers, the resistance to the cracking, values of physical-mechanical properties.