Calcined alumina has become an important support for the development of the ceramic industry
Calcined alumina, an inorganic non-metallic material made from industrial alumina calcined at high temperatures, possesses many remarkable properties. Firstly, its high hardness is one of its hallmarks. Its Mohs hardness reaches 9, second only to diamond. This makes ceramic products made from it exceptionally wear-resistant, maintaining a good appearance and structural stability over long-term use. Secondly, it possesses excellent high-temperature resistance, capable of withstanding temperatures exceeding thousands of degrees Celsius without deformation or damage, a characteristic that makes it particularly useful in the field of high-temperature ceramics. Furthermore, calcined alumina exhibits excellent chemical stability and is not susceptible to chemical reactions with other substances, ensuring the stable performance of ceramic products.
The Main Functions of Calcined Alumina in Glazes
Due to its high purity, high hardness, and excellent chemical stability, calcined alumina is widely used in glazes, particularly for household ceramics, architectural ceramics, and specialty ceramics. In practical applications, it not only significantly improves the hardness and wear resistance of the glaze surface, effectively reducing scratches and wear during use, thereby extending the service life of ceramic products; it also enhances the glaze’s chemical stability, reducing the risk of acid and alkali corrosion, and improving the product’s stain resistance and durability. Furthermore, the appropriate addition of calcined alumina can adjust the glaze’s melting temperature and viscosity, improving its fluidity, avoiding defects such as pinholes and glaze shrinkage, and resulting in a smoother and more even glaze surface. Furthermore, its unique optical properties can help control the glaze’s gloss, adding a delicate texture to matte glazes and enhancing the gloss uniformity of glossy glazes to meet the design requirements of various ceramic products.
In pigment applications, calcined alumina can provide a stable carrier for metal oxide pigments (such as iron oxide and cobalt oxide), inhibit the volatilization or diffusion of pigments at high temperatures, and prevent the glaze from blooming and fading. Especially in high-temperature glazes, it can lock the color concentration and tone consistency, helping to achieve rich and lasting ceramic decorative effects. It is a key support for promoting the development of ceramic colored glazes towards high performance and high stability.