Zirconia has the characteristics of high melting point, high boiling point and high hardness. It is an insulator at room temperature and has excellent electrical conductivity at high temperature. Therefore, it is used as a structural ceramic and functional ceramic material in mechanical, electrical, electronic, optical, biological and Catalysis and other aspects have great application potential.
At the same time, zirconia is also an excellent "supporting role". In the production of advanced ceramics, adding a small amount of zirconia will also greatly improve the performance of other ceramics.
Zirconia Toughened Alumina Multiphase Ceramics
The martensitic transformation characteristics of ZrO2 can improve the fracture toughness and flexural strength of ceramic materials, making them have excellent mechanical properties. In addition, the low thermal conductivity and good thermal shock resistance of zirconia itself can also improve the brittleness of ceramic materials. In summary, toughening mainly utilizes the martensitic transformation characteristics of ZrO2, absorbs the energy of failure generated when ZrO2 transforms from a tetragonal structure to a monoclinic structure, and inhibits the change and extension of cracks.
According to this mechanism, zirconia toughened alumina ceramics (ZTA) can be prepared by introducing zirconia into Al2O3 ceramics. ZrO2 can play the role of phase transformation toughening and micro-crack toughening in Al2O3 ceramics, toughening and reinforcing Al2O3 ceramics, thereby improving the toughness of Al2O3 ceramics. Therefore, ZTA ceramics become one of the most promising materials in structural ceramics. one.
Effect of zirconia on thermal shock resistance of magnesia ceramics
Magnesium oxide has good high temperature resistance and electrical insulation, has strong corrosion resistance to alkaline metal slag, and does not chemically react with magnesium, nickel, uranium, thorium, zinc, aluminum, iron, copper, platinum, etc. , It can be used to prepare crucibles for metal smelting, injection molds for pouring metals, protection tubes for high temperature thermocouples, and lining materials for high temperature furnaces. In the environment of rapid temperature change (that is, thermal shock), the strength of magnesia ceramics will be greatly reduced, spalling or even brittle cracking will occur, which reduces the safety and reliability of magnesia ceramics in service. Therefore, it is of great practical significance to improve the thermal shock resistance of magnesia ceramics and prolong its service life at high temperature.
Influence of zirconia on vitrified bond for superhard abrasive tools
Low-temperature vitrified bond is an important part of the preparation of high-performance vitrified bond superhard abrasives (diamond, cubic boron nitride), and its performance directly affects the comprehensive performance of superhard abrasives. The basic performance requirements of vitrified bond for superhard abrasive tools are high strength, low softening and melting temperature, small thermal expansion coefficient, and good wetting performance at high temperature. In addition, due to the high hardness and good wear resistance of superhard abrasive grains, and most of the ceramic bonds for superhard abrasives are used at relatively high rotational speeds, in order to ensure that the abrasive grains can give full play to their grinding performance, it is required to The vitrified bond for superhard abrasives must have high strength.
Effect of Zirconia on Corundum Ceramics
Corundum ceramic regenerator has the advantages of good chemical stability, high temperature resistance, corrosion resistance and high strength, but it is brittle and has poor thermal shock resistance. At present, there are many literatures about nano-ZrO2 toughening corundum ceramics and improving the thermal shock resistance of corundum ceramics.
Influence of Zirconia on Microstructure and Mechanical Properties of Hot-pressed AlN Ceramics
AlN ceramics have the advantages of high thermal conductivity, excellent electrical properties, and low thermal expansion coefficient, and are often used as an ideal material for circuit packaging substrates. However, compared with ceramic materials such as Si3N4 and SiC, AlN ceramics have lower fracture toughness, which reduces its thermal shock resistance and increases its machining difficulty.
