Zirconia has excellent properties such as high temperature resistance, wear resistance, chemical corrosion resistance, oxidation resistance, good chemical stability, low specific heat and thermal conductivity. It is widely used in aerospace and military industry, mechanical engineering, communications, catalysis, automotive, metallurgy, Energy, biology and other fields. Under different temperature conditions, ZrO2 has three different crystal structures, monoclinic at low temperature, tetragonal at middle temperature, and cubic at high temperature. Among them, the tetragonal crystal form exists in a metastable state, and when the temperature increases, it transforms into a cubic crystal form; when the temperature decreases, it transforms into a monoclinic crystal form.
(1) Application of zirconia in the field of refractories
Because ZrO2 has the characteristics of high temperature resistance and corrosion resistance, it can resist acid or neutral melt erosion, so it is widely used as special
refractory materials, casting ports, molds, high temperature melt launders, and crucibles for melting special metals; It is not wetting with molten iron or steel, so it can be used as a steel bucket, a steel launder, a continuous cast steel injection and a molten steel filter, etc.; because the composite ZrO2 (doped with Y2O3 or CaO) has semiconductor properties at high temperatures, it can Used as a high-temperature heating element used in the air, the maximum operating temperature can reach 2100~2200℃; high-temperature chemical properties are stable, corrosion-resistant, anti-oxidation, non-volatile, and pollution-free. These excellent characteristics determine that zirconia fiber is a top-grade high-grade refractory fiber; the application of zirconia furnace materials greatly increases the life of the furnace. Among them, the sizing nozzle is the key functional material of the tundish, which is mainly used for billet continuous casting. The nozzle diameter is required to remain basically unchanged during the use process to control the flow of molten steel to ensure the normal progress of continuous casting. The application of zirconia sizing nozzle has greatly improved the life of the nozzle.
(2) Application of ZrO2 in special ceramics
Electronic ceramics: The applications of ZrO2 in electronic ceramics mainly include piezoelectric components (such as pyrophoric components, hearing aids, pickups, etc.), filters (used in televisions, radios, radio transceivers, etc.), ultrasonic oscillators (used in Used in submarine sones, fish detectors and depth sounders, etc.), buzzers (used for electronic computer input power identification signals, tune-table electronic computers, digital display watches and alarm clocks, etc.) and high-temperature conductors and other functional ceramics: Stable zirconium dioxide also has semiconducting and sensitive properties, and can be used as a semiconductor material and oxygen detector material. Gas sensors (such as oxygen analyzers and liquid steel oxygen probes, etc.), temperature sensors (used for electronic thermometers, photocopiers, electronic lenses, etc.), sound sensors (used for ultrasonic remote control, submarine sonar, ultrasonic flaw detection and diagnostic equipment, etc.) ), pressure sensors (used for strain gauges, pickups, electronic blood pressure meters, etc.), acceleration sensors (used for accelerometers) and other high-tech automatic control systems, as well as high-temperature solid fuel cell dielectrics and magnetic fluid motor electrodes. Zirconium dioxide has good chemical stability, high hardness, toughness and good biocompatibility. As a bioceramic, it is widely used in artificial teeth, bones and other human implants.
Structural ceramics: Because ZrO2 has low thermal conductivity, high strength and toughness, low elastic modulus, high thermal shock resistance and other characteristics, it can be used as non-lubricated ball bearings in spacecraft and components of jet engines, internal combustion engines and steam turbines (such as Push rods, connecting rods, bearings, cylinder linings and piston caps, etc.); due to the limitation of the metal material itself, the corrosion damage of the metal has a considerable impact on the valve wear resistance, the period of action, reliability, and service life. Zirconia The excellent wear resistance, corrosion resistance, and high temperature thermal shock resistance of ceramic valves can make up for this short board; zirconia full ceramic bearings have anti-magnetic and electrical insulation, wear resistance, corrosion resistance, oil-free self-lubrication, high temperature resistance, and can be used for Extremely harsh environment and special working conditions; Zirconia ceramic tools have the characteristics of high strength, wear resistance, no oxidation, no rust, acid and alkali resistance, anti-static, and no reaction with food; Zirconia grinding balls have the characteristics of high hardness , The wear rate is small, the service life is long, it can greatly reduce the pollution of grinding raw materials, and can well guarantee the product quality. At the same time, the zirconia material has a high density and strong impact energy when used as a grinding medium, which can greatly improve the grinding and dispersion efficiency and can be effective Shorten the grinding time.
