What is zirconia
Zirconia is the natural raw material of zirconia, which mainly consists of zircon and zircon. Zircon is a kind of deep-seated mineral of igneous rock. Its color is light yellow, brown yellow and yellow green. Its specific gravity is 4.6-4.7, hardness is 7.5, and it has strong metallic luster. It can be used as raw material for ceramic glaze.
Zirconium is rich in resources, and its reserves in the earth's crust far exceed those of copper, zinc, niobium and other metals. At present, the proven zirconium resource reserves in the world are about 19 million tons, and there are more than 20 kinds of ores in the world, mainly including the following compounds:
(1) Zirconia and its variants;
(2) Zirconium orthosilicate and its variants;
(3) Heterosexual stone, negative heterosexual stone, zirconium diamond, etc.
In fact, the content of zirconium in the heteromorphic stone and the negative heteromorphic stone is very low and has no industrial value.
Therefore, the main source of zirconium is zirconia. The high-purity zirconia is white. When it contains impurities, it appears yellow or gray.
Generally, it contains hafnium dioxide and is not easy to separate. The density of monoclinic zirconia is 5.6g/m3 and the melting point is 2700 ℃.
Zirconia has excellent properties such as high boiling point and melting point, strong hardness, insulator at room temperature, and conductivity at high temperature. Since 1920s, it has been used as refractories for steelmaking and glass making.
Since the 1970s, with the deeper understanding of zirconia, scientists have further developed the role of zirconia as a structural and functional material. In 1975, Australian scientists used calcium oxide as a stabilizer to produce stable zirconia ceramics, and further improved its toughness and strength by using the toughening effect of zirconia, which effectively broadened the application field of zirconia in structural ceramics.