Thermal shock resistance performance of zirconia ceramics

Thermal shock resistance performance of zirconia ceramics

The magnitude of thermal stress in zirconia ceramic materials depends on the mechanical and thermal properties of the material, and is influenced by the geometric shape of the structural components and environmental media. The thermal shock resistance, as the ability of ceramic materials to resist temperature changes, is the comprehensive performance of the mechanical and thermal properties of ceramic Strength of materials.

The thermal vibration damage of zirconia ceramic materials can be divided into two categories: transient fracture under Thermal shock and cracking, peeling under Thermal shock cycle, as well as overall damaged thermal layer damage.

One is based on the theory of thermoelasticity, which refers to the thermal shock fracture of materials when their inherent strength is insufficient to resist the thermal stress caused by thermal shock temperature difference. According to this theory, if ceramic materials have high strength, thermal conductivity and low coefficient of thermal expansion, Young's modulus of elasticity, Poisson's ratio, thermal radiation coefficient and viscosity at the same time, they will have high resistance to thermal shock. In addition, appropriately reducing the density and heat capacity of the material is also beneficial for improving the thermal shock resistance of ceramic materials.

The other is based on the concept of Fracture mechanics. When the thermoelastic Strain energy in the material is sufficient to pay for the energy required for crack nucleation and propagation and the new surface, cracks will form and spread, which will lead to thermal shock damage of the material. According to this theory, materials with good thermal shock damage resistance should have the highest possible elastic modulus and the lowest possible strength.

Zirconia ceramic rods and zirconia ceramic structural components have outstanding mechanical properties at room temperature. It has a high melting point, good thermal and chemical stability, and can often be used at high temperatures. Thermal shock resistance is one of its important indicators.

Zirconia has three crystal forms: monoclinic, tetragonal, and cubic, and has special phase transition characteristics. These characteristics can be used to optimize its thermal expansion behavior and improve its thermal shock resistance.

Website: https://www.zhengtaifeng.com/