陶瓷Ceramic

陶瓷以离子键和共价键为主，因此硬度高、熔点高、耐腐蚀、耐高温，多为电和热的绝缘体，但缺乏位错滑移能力，韧性差、易脆断，对微裂纹非常敏感。烧结时粉末颗粒通过扩散致密化、晶粒长大，气孔率和晶粒尺寸决定最终性能。氧化锆中的相变增韧、纤维增强陶瓷基复合材料可以提高韧性。

Ceramics are held mainly by ionic and covalent bonds, so they are hard, high-melting, corrosion- and heat-resistant and usually electrical and thermal insulators, but dislocations barely move, so they are brittle and highly sensitive to small cracks. During sintering powder particles densify by diffusion and grains grow, and porosity and grain size set the final properties. Transformation toughening in zirconia and fibre-reinforced ceramic-matrix composites improve toughness.

陶器的历史可追溯到约两万年前，中国江西仙人洞遗址出土了世界最早的陶器之一。商代出现原始瓷，东汉成熟的青瓷在浙江烧成，唐宋元明清各代名窑辈出，瓷器英文 china 即源于中国。1709 年德国伯特格尔在迈森成功烧制硬质瓷。20 世纪中叶起氧化铝、氮化硅、碳化硅、压电陶瓷、陶瓷超导体等先进陶瓷迅速发展。

Pottery goes back about 20,000 years, and Xianrendong Cave in Jiangxi, China, has yielded some of the world's oldest. Proto-porcelain appeared in the Shang dynasty, mature celadon was fired in Zhejiang in the Eastern Han, and famous kilns flourished through the Tang to Qing dynasties; the English word china comes from China. In 1709 Böttger produced hard-paste porcelain at Meissen in Germany. From the mid-twentieth century advanced ceramics such as alumina, silicon nitride, silicon carbide, piezoelectrics and ceramic superconductors developed rapidly.

传统陶瓷用于日用器皿、建筑卫生陶瓷和耐火材料；结构陶瓷（Si₃N₄、SiC、ZrO₂、Al₂O₃）用于轴承、刀具、发动机部件和防弹装甲；功能陶瓷包括电容器介质（BaTiO₃）、压电陶瓷（PZT）、半导体陶瓷（热敏、压敏电阻）、固体电解质和透明陶瓷；生物陶瓷（羟基磷灰石、氧化锆）用于人工骨和牙冠；航天飞机的防热瓦也是陶瓷材料。

Traditional ceramics serve tableware, building and sanitary ware, and refractories; structural ceramics (Si₃N₄, SiC, ZrO₂, Al₂O₃) are used in bearings, cutting tools, engine parts and armour; functional ceramics include capacitor dielectrics (BaTiO₃), piezoelectrics (PZT), semiconducting ceramics (thermistors, varistors), solid electrolytes and transparent ceramics; bioceramics (hydroxyapatite, zirconia) make bone substitutes and dental crowns; and the Space Shuttle's heat-shield tiles were ceramic.