Zirconia has excellent properties such as high temperature resistance, corrosion resistance, wear resistance, good thermal stability, high refractive index, and good thermal shock resistance. It is one of the emerging materials that have developed rapidly in recent years. At present, the preparation methods of zirconia mainly include chemical method and electric melting method. Among them, the high-purity zirconia produced by chemical method has particularly excellent performance, and the product is easy to control in the production process, but the chemical method has a long process flow and decomposition. The reagent consumption is large and the product cost is high, so it cannot be widely used in the fields of ordinary ceramics, refractory materials and ceramic color glazes.
Production process of fused zirconia
The electrofusion stabilized zirconia process can be divided into two types according to the raw materials: one is to use zircon sand as the raw material, and complete the two processes of desiliconization and stabilization through a single smelting in an electric arc furnace, which is called the one-time smelting method; One is to use electric fusion desiliconized zirconium as the raw material, mixed with stabilizers and smelted in an electric furnace to form stable zirconia, which is called the secondary smelting method.
Application of Fused Zirconia---Application in ceramic color and glaze
Ceramic pigments are the most important ceramic decorative materials. Among ceramic pigments, zirconium-based pigments have the characteristics of good color stability, strong color rendering power, good miscibility and pure color. Therefore, fused zirconia is more and more popular. The more widely used it is in the production of ceramic color glaze. Zirconium-based ceramic pigments mainly include zirconium vanadium blue, zirconium praseodymium yellow, vanadium zirconium yellow, zirconium iron red, zirconium yellow and other types. In the process of synthesizing zirconium silicate, transition metal and rare earth metal ions can enter its crystal lattice to form a bright and stable toner.
Application in refractory materials
Fused zirconia is a new high-grade refractory material with high melting point, good chemical stability and thermal stability. It is widely used in steel production, glass production, non-ferrous precious metal production, engineering ceramics, furnace lining refractories, abrasives, pigments, Electronics production and other industries, producing products that require high temperature resistance, corrosion resistance, erosion resistance, good chemical stability, low thermal conductivity, high hardness, wear resistance and other excellent properties, such as sizing nozzles, zirconium corundum, zirconium mullite, pipes Nozzles, nozzles, crucibles, ceramic pigments, surface coatings, abrasives, grinding media, engineering ceramics, kiln furniture, etc.
Application in investment casting
For fused zirconia, investment casting is also a major dedicated market. Such as the casting of special products such as aerospace engine turbine blades and golf clubs. Zirconium oxide is generally used as the model coating. Zircon is used in investment casting because of its ability to form actual contact with hot metal alloys, thereby protecting the mold from thermal shock.
Application in abrasive materials
Polishing tools used in the ceramic industry, such as grinding wheels, non-metallic blade products used in stone cutting, these products are made by mixing zirconia and alumina according to a certain formula ratio to make coarse abrasive particles, which are processed after thermal processing Grinding wheels or coated on the surface of grinding tools can be used to polish steel and metal alloys.
Application in advanced ceramics and special products
For stabilized zirconia, electronic component firing regulating plates are a major market. Stabilized zirconia is also used in oxygen sensors and fuel cell separators because of its ability to allow oxygen ions to move freely in the crystal structure under high temperature conditions. . This high ionic conductivity (and low-variable electronic conductivity) makes it one of the most potential electrical ceramic materials. Chemical grade zirconia is often used in electrofusion products, and other specialty products markets include suction pumps and high-value parts, special tool parts, and brake pad linings. The gem market also uses fully stabilized cubic phase yttria stabilized zirconia, which is used as a cheap substitute for gems in the jewelry industry.