Surface integrity and flexural strength improvement in grinding partially stabilized zirconia

Zirconia has been used in medical applications since last few years and an optimum and cost-effective condition in grinding zirconia has drawn industrial attention. This paper aimed to improve and control the surface integrity, flexural strength and grinding cost in grinding partially stabilized zirconia (PSZ) using a diamond grinding wheel. The phase transition and grindability of PSZ were also evaluated. Ground surfaces analysis shows that all samples subjected to the grinding presented an increase in surface integrity, and the subsurface damages 100 below the surface were reduced from 3.4% to 0.9%. The flexural strength using 3 point bending test (3PB) shows that grinding increased the flexural strength more than 29% which is the result of higher surface integrity. The ground surfaces were analyzed using X-ray diffraction (XRD) and the results shows that T-M phase transition trend is in accordance with the surface integrity. In other words, XRD analyses prove that T-M phase transition results in higher flexural strength and surface integrity. It was also observed that in the best condition, the grinding cost was reduced by 72%. It can be concluded that controlling the grinding condition in grinding PSZ will result in the increase of the surface integrity and flexural strength. A mathematical model was created to find an optimum condition using response surface method (RSM). It is observed that feed rate has greater effect on the outputs rather than depth of cut.