氧化锆增韧堇青石陶瓷的研究

A STUDY OF ZIRCONIA TOUGHENED CORDIERITE CERAMICS (ZTCC)

添加分散的氧化锆对多晶体堇青石进行了增强和增韧。含10％(按质量计,下同)ZrO_2的氧化锆增韧堇青石陶瓷(ZTCC)的抗弯强度(130MP_a)较1400℃,6h制备的人工合成高纯多晶堇青石的(74.3MP_a)有明显提高。含有5％ZrO_2和1％CaO二元弥散相粒子的ZTCC的断裂韧性增大至2.83MPa·m^(1/2)。当加入15％Y-TZP,样品的抗弯强度和断裂韧性分别高达188MPa和3.2MPa·m_(1/2);增强和增韧的辐度分别为153％和100％。ZTCC的主要增韧机理为裂纹偏转和曲折扩展机理及曼徽裂纹增韧机理。含有ZrO_2弥散相的ZTCC保持了高纯堇青石陶瓷相同的抗热冲击破坏性能;而含有ZrO_2和CaO二元弥散相的ZTCC显示了更好的抗热冲击损伤性。

Strengthening and toughening of the polycrystalline cordierite ceramics adding with different amounts of ZrO_2 dispersed particles were investigated. Synthetic highly pure cordierite (HPC) (1400℃, 6h) has a very low linear thermal expansion coefficient of 1.54×10^(-6)/℃, a flexural strength of 74.3 MPa and a fracture toughness of 1. 60 MPa·m^(1/2). The flexural strength can be increased to 130 MPa by adding 10％ (in mass) ZrO_2 dispersed particles in ZTCC, and the fracture toughness of ZTCC with adding 5％ (in mass) ZrO_2 and 1％ (in mass) CaO dispersed particles arrives at the level of 2. 83 MPa·m^(1/2). The effects of strengthening and toughening by adding superfine 15％ (in mass) Y-TZP dispersed particles on ZTCC are so remarkable that the flexural strength and fracture toughness can be increased to 188 MPa and 3. 2 MPa·m^(1/2) respectively, which implies that the increase of strengthening and toughening is 153％ and 100％ respectively. The main toughening mechanism of ZTCC is the mechanism of crack deflection and microcracking. ZTCC containing ZrO_2 dispersed particles has the same thermal shock resistance as HPC ceramics, while ZTCC shows better thermal shock resistance by adding with ZrO_2 and CaO dispersed particles. It seems that ZTCC is suitable for the use of thermal-shock-resistant material because of its low thermal expansion and relatively good mechanical properties.