Estimation of Hamaker constants of ceramic materials from optical data using Lifshitz theory

The Hamaker constants of eight different ceramic materials, 6H-SiC, tetragonal, partially stabilized ZrO2 (3% Y2O3), beta-Si3N4, alpha-Al2O3, Y2O3, sapphire (single-crystal alpha-Al2O3), MgO, MgAl2O4, and fused silica, across air, water, and n-dodecane at room temperature and across silica at 2000 K have been calculated from optical data using the Lifshitz theory. Spectroscopic ellipsometry was used to measure the photon energy dependence of the refractive index, rt, and the extinction coefficient, k, in the visible and near-UV range on several important ceramic materials. This relatively simple, nondestructive technique has proved to yield reliable optical data on sintered, polycrystalline materials such as Si3N4, SiC, ZrO2, Al2O3, and ZnO. For the other materials, Y2O3, sapphire, MgO, MgAl2O4, and fused silica, optical data from the literature were used to calculate the Hamaker constants. The calculated Hamaker constants were estimated to be accurate within +/-10%.