Main preparation technology of special ceramics is forming and sintering of boron carbide powder preparation of plastic is very poor, the grain boundary migration resistance is very big, when the solid surface tension is very small, it is all the factors hindering the research on the sintering Of atmospheric pressure sintering without any additives to get high density products, the required conditions are harsh, such as powder particle size should be as small as possible (less than 3 microns), powder particle size greater than 8 microns without atmospheric pressure sintering additives is impossible;Sintering temperature is high (2250~2280), close to the melting point of boron carbide (2400), so atmospheric sintering usually adds a variety of sintering additives to promote sintering additives can be divided into metal and inorganic non-metal two categories.

When sintering temperature is less than 1800℃ and adding Gr, Co, Ni, Al, glass and other atmospheric pressure sintering, the final density is less than 78%.The addition of Si, Al, Mg, TiB2, GrB2, SiC, Be2C and SiC+Al, B+C, B+Si+W2B5 can improve the sintering density at higher temperature (2150 ~ 2250℃).The advantage of using a small amount of carbon as sintering additive is that it does not introduce the third element except carbon and boron. Compared with adding the third element (such as Si, Al, Mg, Ti, F, Ni, etc.) as additives, the structure and properties of boron carbide material have no great changes, so it has received special attention.The added carbon is usually obtained by thermal decomposition of organic precursors such as glucose and phenolic resins.Hot densification mainly includes two methods: hot pressing and hot isostatic pressing.