Grinding Force and Microcrack Density in Abrasive Machining of Silicon Nitride

H. H. K. Xu, L. Wei, and S. Jahanmir, “Grinding Force and Microcrack Density in Abrasive Machining of Silicon Nitride,” J. Mat. Res., 10 (1995) 3204-3209.

The relationship between grinding forces and the material’s resistance to microfracture is investigated in abrasive machining of silicon nitride ceramics. Surface grinding is performed on two forms of silicon nitride with different microstructures, and the grinding forces are measured. In addition, single-point scratching is performed on polished surfaces to amplify the damage associated with the action of an individual abrasive particle in grinding. A thermal wave measurement technique is then used on the cross sections to characterize the density of subsurface microcracks associated with scratching. Compared to a fine-grain silicon nitride, the density of microcracks in a course-grain silicon nitride is significantly larger, while the grinding force is smaller. The smaller grinding force for the coarse-grain silicon nitride is attributed to the ease of local intergranular microfracture and grain dislodgement during grinding.

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