Non-flammable; high heat resistance; high chemical stability; non-aging; high hardness; good compressive strength; however, it is very brittle and has low resistance to rapid temperature changes.
The main performance characteristics of ceramic materials are based on their atomic bonding structure (mainly ionic or covalent bonds) and crystal properties. Specifically, the derivation is as follows:
1. Non-flammability: Due to their high melting point and chemical stability, ceramic materials are not easily oxidized or decomposed at high temperatures, thus they do not burn.
2. High heat resistance: The strong bonding structure of ceramics allows them to withstand high temperatures (typically exceeding 1000°C), and their low coefficient of thermal expansion makes them suitable for high-temperature environments.
3. High chemical stability: Ceramic surfaces are highly reactive and do not easily react with acids, alkalis, or other chemicals, exhibiting good corrosion resistance.
4. Non-aging: The stable structure of ceramics, the absence of organic components, and the resistance to degradation or performance decline over long-term use.
5. High hardness and good compressive strength: The dense crystal structure and close atomic arrangement result in high hardness (e.g., alumina has a hardness of 9 Mohs), and compressive strength is superior to tensile strength. High brittleness: Ceramics lack a dislocation slip mechanism, making them prone to brittle fracture under impact and exhibiting poor ductility.
6. Low resistance to rapid temperature changes: Due to poor thermal conductivity and uneven coefficients of thermal expansion, internal stress concentrates during sudden temperature changes, leading to cracking or breakage.
In summary, these characteristics stem from the microstructure of ceramics. Their positive properties make them suitable for refractory, corrosion-resistant, and structural materials, while their negative properties limit their impact resistance and thermal shock resistance applications.
