堇青石/氮化铝陶瓷的组成、结构及力学性能

Phase,Structure and Mechanical Properties of Cordierite/AIN Ceramics

在由氧化铝、滑石和粘土组成的堇青石预合成粉中加入质量分别为1 wt%、3 wt%和5 wt%的金属铝粉,于氮气保护环境中经1370℃热处理得到堇青石/氮化铝复相陶瓷。分别利用X射线衍射仪和扫描电子显微镜分析了其物相组成和显微形貌,并用三点弯曲试验机检测了所制材料的断裂强度和断裂位移。研究结果表明,在氮化热处理过程中,随着反应程度的不同,金属铝粉原位生成细丝状AlN晶须、纤维,以及强化烧结结构。AlN晶须、纤维的生长过程属于的气-液-固(VLS)晶体生长机制。所形成的AlN晶须、纤维,以及强化烧结结构有利于增强复合材料的力学强度和韧性。

The cordierite/aluminum nitride composite ceramic was obtained by adding 1 wt%,3 wt%,and 5 wt%metal aluminum powder to the pre synthesized powder of cordierite composed of alumina,talc,and clay,under 1370℃ treatment in a N2 protected environment.The phase composition and microstructure of the materials were analyzed by using X-ray diffractometer and scanning electron microscope,and the fracture strength and displacement of the material were measured using a three-point bending test machine.The research results indicate that during the nitriding heat treatment process,with varying degrees of reaction,the metal aluminum powder in-situ generates fine wire like AIN whiskers,fibers,and strengthens the sintered structure.The growth process of AiN whiskers and fibers belongs to the gas liquid solid(VLS)crystal growth mechanism.The AiN whiskers,fibers,and reinforced sintered structure formed are beneficial for enhancing the mechanical strength and toughness of the composite material.