廉价非金属资源合成环境友好Sialon/SiC复相陶瓷

以大量的固体废弃物金属尾矿和天然的可再生资源黄河泥沙为主要原料,利用炭黑作还原剂,采用碳热还原氮化法合成了Ca-α-Sialon/SiC复相陶瓷粉.用X射线衍射法测定产物相组成及相对含量,研究了合成温度和保温时间对反应过程的影响.结果表明:合成温度对Ca-α-Sialon/SiC陶瓷粉体的合成过程影响显著,随着合成温度升高,产物中Ca-α-Sialon相含量增大,1580 ℃时Ca-α-Sialon相含量达最大.保温时间对产物相组成的影响不十分显著,但较长的保温时间可以使还原氮化反应进行得更充分,保温8 h的试样中Ca-α-Sialon相含量达到了81%.合成过程中SiO的挥发导致试样较大的质量损失,且随着合成温度的升高和保温时间的延长而增大.

Synthesis of Environment-Friendly Sialon/SiC Multiphase Ceramics from Cheap Nonmetallic Resources

With abundant solid waste of metallic tailings and recycling resources of Yellow River sand as raw materials, carbon black as reduction agent, Ca-α-sialon/SiC powders were synthesized by carbothermal reduction nitridation(CRN). Phase composition of reaction products was determined by X-ray diffractometry. The influence of synthesis temperature and holding time on synthesis was discussed. The results show that synthesis temperature affects the formation of Ca-α-sialon/SiC significantly. Content of Ca-α-sialon in the products increases with the increase of synthesis temperature and reaches the maximum at 1580 ℃, which is assumed to be the best synthesis temperature. Holding time does not affect the phase composition significantly, but with holding time expanding, carbothermal reduction nitridation reaction proceeds much sufficiently. Content of Ca-α-sialon in the samples reaches 81% at 8 h, which is perfect holding time. Volatilization of SiO results in great mass loss of the samples and increases with synthesis temperature increasing and holding time expanding.