摘要
The strong covalent bonding characters of zirconium diboride( Zr B2) and hafnium diboride( Hf B2) with natural hexagonal Al B2-type crystal structure give them high melting points( 〉 3 200 ℃), high bending strength, high elastic modulus and high hardness.Zr B2- and Hf B2-based ceramics are promising candidates for the thermal protection components of propulsion systems,rocket nozzles,sharp leading edges and nose cones. This paper introduces the recent research progress on Zr B2- and Hf B2-based ceramics,including the synthesis methods of the boride powders,the sintering methods of the boride-based ceramics and their properties.The advantages of different synthesis methods and sintering methods are compared. The influence factors on the mechanical properties,oxidation resistance and thermal shock resistance are summarized.
The strong covalent bonding characters of zirconium diboride( Zr B2) and hafnium diboride( Hf B2) with natural hexagonal Al B2-type crystal structure give them high melting points( 〉 3 200 ℃), high bending strength, high elastic modulus and high hardness.Zr B2- and Hf B2-based ceramics are promising candidates for the thermal protection components of propulsion systems,rocket nozzles,sharp leading edges and nose cones. This paper introduces the recent research progress on Zr B2- and Hf B2-based ceramics,including the synthesis methods of the boride powders,the sintering methods of the boride-based ceramics and their properties.The advantages of different synthesis methods and sintering methods are compared. The influence factors on the mechanical properties,oxidation resistance and thermal shock resistance are summarized.
基金
Financial supports from the National Natural Science Foundation of China ( No. 51272266 )
the Science and Technology Commission of Shanghai ( No. 15ZR1445200 )
the State Key Laboratory of High Performance Ceramics and Superfine Microstructure