Preparation of boron carbide stainless steel composites by spark plasma sintering

The B₄C-stainless steel composites with B₄C mass fraction of 4.00% were prepared by spark plasma sintering (SPS) method, using B₄C microspheres and 304 stainless steel powders as the raw materials. The density of the composites was tested by the drainage method, the microstructures of B₄C and stainless steels were analyzed by scanning electron microscope (SEM), and the effects of sintering temperature and pressure on the density and microstructure of the composites were investigated. The results show that, the thickness of the interfacial reaction layer increases with the increase of sintering temperature. Meanwhile, increasing the sintering pressure can significantly reduce the sintering temperature, which inhibits the growth of the interfacial reaction layer between B₄C and stainless steels. When the pressure reaches 150 MPa, the relative density of the composites can reach 99.5% after sintering at 950 ℃ for 6 min, and the thickness of the interfacial reaction layer is less than 5 μm.