叶蜡石、白云石对陶瓷结合剂磨具微观结构和性能的影响

Effect of pyrophyllite and dolomite on the microstructure and properties of vitrified bond grinding tools

本文研究了在粘土、长石质结合剂中引入叶蜡石和白云石对碳化硅磨具微观结构和性能的影响,结果表明,在一定范围内引入不同比例的叶蜡石和白云石:(1)可使结合剂的耐火度成线性降低。同时,也不同程度地影响了磨具烧结体的微观结构和性能;(2)可促进在烧结过程中莫来石的形成,降低结合剂的热膨胀系数,加强了结合剂与磨料的匹配性,提高了磨具的抗折强度和抗冲击强度;(3)在一定温度范围内还可防止碳化硅磨具出现黑心现象,拓宽了碳化硅磨具的烧结温度适应范围。通过实验发现:叶蜡石和白云石最佳含量为30%,与原结合剂相比,结合剂耐火度降低了55℃,平均热膨胀系数降低了30%,磨具抗折强度提高了27%,磨具抗冲击强度提高了22%。

This paper reports the effect of pyrophyllite and dolomite,which are added to clay and feldspar, on the microstructure and properties of vitrified bond grinding tools. The studies indicate that different content of pyrophyllite and dolomite can cause the following three cases ： （ 1 ） making the refractory point decrease linearly and, to some extent, influencing the microstructure and properties of sintered body; （2）acceleratingmullite formation during sintering, reducing thermal expansion coefficient of bond , reinforcing the matching nature and improving the flexural strength and shock strength; （3）preventing SiC grinding tool from generating black core , expanding suitable sintering temperature range of SiC grinding tool. Experiments show the optimum content of pyrophyllite and dolomite is 30% ; in contrast to original bond,the refractory point of bond is reduced by 55℃ ,the average coefficient of thermal expansion is reduced by 30% and flexural strength and shock strength of grinding tool are increased by 27% and 22% respectively.