Apparently, the discrete droplet phase separation structures were not formed in the glaze, indicating that the Rayleigh scattering could not occur on the glaze surface. Hence, the glaze color was deep brown instead of blue. When the size of phase separation droplets became larger, the scattering intensity (I (λ) incident) was smaller and the opalescence blue formed by structural color was lighter. So the blue of glaze surface was lighter with the increasing of firing temperature. In order to evaluate the suitability of materials for series production in technologies, the properties of the produced
samples fired at different temperatures were measured. And the abrasive resistance and hardness are summarized in Fig. 9.