材料专业英语 陶瓷材料 Ceramic Materials.ppt

Ceramic Materials Company name LOGO School of materials science and engineering 1 Introduction 1.1 what is Ceramics? A product obtained through the action of fire upon earthy materials →Inorganic, nonmetallic solids, usually oxides, nitrides, or carbides. Ceramics are typically crystalline in nature and are compounds formed between metallic and non-metallic elements. 1.2 Typical properties Moderate density Low electrical conductivity insulators Strong compressive strength tensile strength Low - moderate thermal conductivity insulators Brittle Hard Very high hardness raw materials are plentiful and inexpensive many ceramics transparent to light translucent, or opaque High elastic modulus - greater than metals Excellent wear resistance because of high compressive strength and hardness Good resistance to chemical attack Main limitation: ? very brittle and they are flaw sensitive ? Cracks and other flaws are always present 1.3 Classification ? advanced ceramics also known as engineering or technical ceramics, refer to materials which exhibit superior mechanical properties, corrosion/oxidation resistance, and thermal, electrical, optical or magnetic properties. 2 Nature of Ceramics 2.1 Porosity and Density 2.2 Structure of Ceramics Crystal phase, glass phase, pore 3 Ceramic Processing Chemical Processes: Sol-gel processing solid-phase sintering liquid-phase sintering mechanical processing Physical vapor deposition(PVD) Chemical vapor deposition(CVD) A common technique for consolidating ceramic powders Atomic diffusion mass transfer(particles to open spaces) tremendous amount of shrinkage cracking, distortion /or residual stresses Reaction formed nonoxide ceramics Sintering of ceramic powders Properties of Ceramics Mechanical properties Strong: h