Thermal Damage Control for Dry Grinding of MgO/CeO2 Glass Ceramic

MgO/CeO2 glass ceramic is a key solid catalyst and accelerant produced by raw mixing, prilling and pressure sintering. Grinding, as a high–efficiency machining method was used to obtain MgO/CeO2 glass ceramic components with accurate size to meet the size requirements of design. However, thermal damage occurring on the ground surface may change the properties of the components and affect their performance in subsequent applications. In this work, a grinding thermal model was established and validated by experiments. On the basis of this thermal model, the grinding temperature can be controlled to < 100 oC by selecting optimal grinding parameters and thus prevent grinding burn. The mechanism of potential chemical reactions on the grinding surface was further studied by analysing the transient temperature jump at a grain wear flat area and comparing the change in element mass fraction before and after grinding. The performance of a normal resin–bond diamond wheel and a resin–bond wheel with Ni–P alloy coating on the diamond grains was compared. Results showed that the latter intensified the redox reaction because of the catalytic actions of Ni and P, and the mass fraction of each elements on the workpiece surface shows obvious uneven distribution due to the surface spalling of Ni–P alloy. All these results indicated that key issues are the optimal setup of process parameters to control the grinding–zone temperature and the selection of a proper grinding wheel to avoid catalytic elements such as Ni and P.