1. Introduction and use of alumina ceramics
Introduction
Alumina ceramics is a ceramic material with alumina (Al2O3) as the main body, used in thick film integrated circuits. Alumina ceramics have good conductivity, mechanical strength and high temperature resistance. It should be noted that ultrasonic cleaning is required. Alumina ceramics is a kind of ceramics with a wide range of uses. Because of its superior properties, it has become more and more widely used in modern society to meet the needs of daily use and special properties.
use
Alumina ceramics are divided into two types: high purity type and ordinary type. High-purity alumina ceramics are ceramic materials with an Al2O3 content of more than 99.9%. Because their sintering temperature is as high as 1650-1990℃, and the transmission wavelength is 1 to 6 μm, they are generally made into molten glass to replace platinum crucibles; use its light transmission It can be used as a sodium lamp tube and can be used as an integrated circuit substrate and high-frequency insulating material in the electronics industry.
2. Introduction and use of zirconia ceramics
Introduction
Zirconia ceramics, ZrO2 ceramics, have high melting and boiling points, high hardness, insulators at room temperature, and electrical conductivity at high temperatures. Pure ZrO2 is white, yellow or gray when it contains impurities, and generally contains HfO2, which is not easy to separate. The world's proven zirconium resources are about 19 million tons, and zirconium oxide is usually made from zirconium ore.
There are three crystal states of pure ZrO2 under normal pressure: monoclinic zirconia, tetragonal zirconia and cubic zirconia. The above three crystal types exist in different temperature ranges and can be transformed into each other: the relationship between temperature and density
(1) Monoclinic zirconia temperature <950℃, density 5.65g/cc.
(2) Tetragonal zirconia temperature 1200-2370℃, density 6.10g/cc
(3) Cubic zirconia temperature>2370℃, density 6.27g/cc2,
use
Zirconia ceramics are widely used in the field of structural ceramics because of their high toughness, high bending strength and high wear resistance, excellent thermal insulation performance, and thermal expansion coefficient close to steel. Mainly include: Y-TZP grinding balls, dispersion and grinding media, nozzles, ball valve seats, zirconia molds, micro fan shafts, optical fiber pins, optical fiber sleeves, drawing dies and cutting tools, clothing buttons, watch cases and watches Belts, bracelets and pendants, ball bearings, light golf clubs and other room temperature wear-resistant parts, etc.
3. Comparison results of zirconia ceramics and alumina ceramics Compared with alumina ceramics, zirconia ceramics are more wear-resistant. The reason is that the sintering temperature of zirconia ceramics is higher. The density is twice as high as alumina ceramics.
