烧结陶瓷结合剂碳化硅磨具显微结构研究

Microstructures of sintered vitrified bond silicon carbide grinding wheel

通过电子探针微区分析研究了黏土-长石-石英系烧结陶瓷结合剂碳化硅磨具的显微结构特征,重点研究了结合剂的显微结构。结果表明:结合剂呈典型的烧结状态,有大量的相界和微细裂纹,结合剂和磨粒的结合紧密程度不一;结合剂中有尺寸较大的气孔,最大可达50μm。能谱分析和元素面分布分析表明:结合剂物相主要由玻璃相和残留石英组成,在较大颗粒的残留石英内部及其周围发育有裂纹。此外,本文对磨具显微结构与磨具性能之间的关系作了理论探讨。

Microstructures of sintered vitrified bond have an important effect on the behaviour of the silicon carbide grinding wheel. The paper mainly studied the microstructures of sintered vitvitied bond silicon carbide grinding wheel. The results showed the bond had the typical sintered state. There were many phase boundaries and microcracks in the bond. The degree of bonding between bond and abrasive grains was not the same in different parts. Some large size pores were found in the bond,and the largest pore was 50 μm in diameter. The energy spectrum analysis and elements plane distribution observation proved that the phases of the bond were composed of glass and residual quartz particles. Three kind of microcracks were found in and around the residual quartz particles,including the intragranular crack within the residual quartz grains with a relatively straight cracks,the circumferential crack in the close vicinity of a quartz particle in the form of circular arc,and the microcrack within the glass around the residual quartz particle. There were obvious microcracks when the size of residual quartz particle was 25 μm. No microcrack was found when the size of the residual quartz particle was less than 10 μm.The relationship between the microstructures of the grinding wheel and their performances was discussed theoretically.