1. Introduction to zirconium boride ceramics
Zirconium boride ceramics is one of the most important and commonly used materials in boride ceramics. There are three structures in the ZR-B system, namely ZrB, ZrB2, and ZrB12, where ZrB2 is stable over a wide range of temperatures.
Zirconium boride powder
2. Preparation of zirconium diboride powder
ZrB2 powder is mainly prepared by reducing boride with ZrO2. The reductant is carbon or B4C. The equation is as follows: 3ZrO2 B4C 8C B2C3→3ZrB2 9CO
3. Manufacturing process of zirconium diboride ceramics
For the production of tubular products, such as temperature measuring sleeves, add 8%~10% industrial syrup, starch and dextrin to ZrB2 fine powder. The mixture of oleic acid is used as a binder to make a plastic billet, which is molded by extrusion, dried naturally, and then dried in the oven at 80°C. The billet is buried in graphite fine powder or ZrB2 fine powder and subjected to pre-fired at 400℃, to remove the binder, and finally in a hydrogen atmosphere sintering at 2000~2100℃.
When using isostatic pressing, add 1% oleic acid to the ZrB2 powder, pre-press it under a pressure of 200.0~300.0MPa. Crush through a 12-mesh sieve, put the material into a mold, and after pressing under a pressure of 200.0MPa, put the damaged substances into a graphite boat and put it in ZrB2 powder of 0.5-1mm is heated to 2050℃ for sintering in a hydrogen atmosphere.
4. Properties and applications of zirconium diboride ceramics
Zirconium diboride ceramics have high hardness, good electrical conductivity, thermal conductivity and chemical stability. ZrB2 ceramics are mainly used for high temperature thermocouple protection sleeve, heating element, casting mold, crucible of metallurgical metal, etc.