Properties and Applications of Zirconia Structural Ceramics

Zirconia structure ceramic monoclinic ZrO2→tetragonal ZrO2→cubic ZrO2→melt 1170℃, 2370℃, 2715℃ natural ZrO2 and ZrO2 obtained by chemical method belong to the monoclinic crystal system. The transition between the monoclinic and tetragonal forms is accompanied by a volume change of around 7%. When heated, it is transformed from monoclinic ZrO2 to tetragonal ZrO2, and the volume shrinks, and when cooled, it is transformed from tetragonal ZrO2 to monoclinic ZrO2, and its volume expands. But this shrinkage and expansion do not occur at the same temperature, the former is about 1200°C and the latter is about 1000°C.
Due to the volume change caused by the transformation of the crystal form, it will cause cracking, so it is difficult to produce pure zirconia ceramics. The phase transition temperature is lowered below room temperature, making high temperature stable

Production and application of zirconia ceramics

In 1975, RG Garvie in Australia used calcium oxide as a stabilizer to obtain partially stabilized zirconia ceramics, and used the effect of zirconia martensitic transformation and toughening for the first time to improve toughness and strength, greatly expanding the use of zirconia ceramics in structural ceramics. application in the field.

Zirconia ceramic bearings

Zirconia all-ceramic bearings have the characteristics of anti-magnetic and electrical insulation, wear resistance, corrosion resistance, oil-free self-lubrication, high temperature resistance, high cold resistance, etc., and can be used in very harsh environments and special working conditions. At present, zirconia ceramic bearings have been used in miniature cooling fans, and their product life and noise stability are superior to traditional ball and sliding bearing systems. Foxconn is the first to use zirconia ceramic bearings in computer cooling fans.

Zirconia ceramic valve

At present, the valves commonly used in various industries in my country are metal valves, and the use of metal valves has a history of more than 100 years. Although there have been changes in materials and structures during this period, due to the limitations of the metal materials themselves, the corrosion and damage of metals will affect the valves. The action period, reliability and service life of wear resistance have a considerable influence. The action of mechanical and corrosion factors on the metal greatly increases the total wear of the contact surface. During the valve operation, the friction surface is due to the simultaneous The mechanical action and the chemical or electrochemical interaction between the metal and the environment result in wear and tear. For the valve, the climatic conditions of its pipeline are complex; hydrogen sulfide, carbon dioxide and certain compounds in oil, natural gas and oil reservoir water and other media. The appearance of some organic acids increases the destructive power of the surface, thereby rapidly losing the ability to work. Zirconia ceramic valve has excellent wear resistance, corrosion resistance and high temperature thermal shock resistance, which can be competent in this field.

Zirconia Abrasives

Zirconia grinding balls have high hardness, low wear rate, long service life, can greatly reduce the pollution of grinding raw materials, and can ensure the quality of products. Improve the grinding and dispersing efficiency, which can effectively shorten the grinding time. Good chemical stability determines its corrosion resistance and can be used in acidic and alkaline media. The zirconia ceramic grinding ball researched and developed by the China Academy of Building Materials has a wear rate of only 0.04/24h, and is widely used as grinding media in ball mills, vibration mills, planetary mills and stirring mills.