Wear resistance glass-ceramics with a gahnite phase obtained in CaO-MgO-ZnO-Al2O3-B2O3-SiO2 system

The thermal conditions for obtaining the glass-ceramic material of Al0.107B0.374Mg0.043Zn0.282Ca0.100Si0.927O3 with a crystalline phase in the form of gahnite (ZnAl2O4) were specified. The activation energy Ea and the Avrami parameter n for the crystallisation process were determined with the non-isothermal DTA procedure. The maximum temperatures of crystallisation of phases, depending on the rate of heating, ranged between 800–840 °C for willemite and 870–915 °C for gahnite. The homogeneous crystalline spinel phase was obtained by heat treatment above 1000 °C. Precipitation solely of a ghanite phase from glass-ceramic causes a relative increase in its fracture toughness and wear resistance compared to the two-phase materials, i.e., KIC = 2.12–1.65 MPam1/2 and ws = 0.21 × 10−4 mm3/Nm to ws = 1.43 × 10−4 mm3/Nm.