添加固体润滑剂的Al_2O_3/TiC陶瓷材料力学性能和显微结构

Mechanical properties and microstructure of Al_2O_3/TiC ceramics with the addition of solid lubricants

采用热压工艺制备了添加固体润滑剂MoS2、BN、CaF2的A l2O3/TiC陶瓷材料,测量了其力学性能和分析了其显微结构.结果表明,添加固体润滑剂的A l2O3/TiC陶瓷比未添加时的力学性能有大幅下降,其中A l2O3/TiC/CaF2陶瓷材料的力学性能最好,当CaF2含量为10%时,A l2O3/TiC/CaF2陶瓷材料的强度和硬度最高,分别达到了589MPa和HV1537;而添加BN的A l2O3/TiC陶瓷材料的力学性能最差.XRD衍射结果和微观结构显示,添加MoS2的A l2O3/TiC材料中的MoS2发生分解,基体中存在较多的气孔;添加BN的A l2O3/TiC材料中的BN与A l2O3反应生成A lN,造成大量裂纹的产生,致使材料的强度和硬度都大幅下降;A l2O3/TiC/CaF2陶瓷材料中的CaF2在烧结过程中没发生化学反应,复合材料晶粒大小均匀,基体组织成网状结构,有利于提高材料的强度.

The Al2O3/TiC ceramic materials with the addition of MoS2, BN, CaF2 were produced by means of hot - pressing. The mechanical properties were measured and microstructure was analyzed. It is found that the mechanical properties of the Al2O3/TiC ceramics with the additions dropgreatly among which Al2O3/TiC/CaF2 ceramic composites have the best mechanical properties and the Al2O3/TiC with 10% CaF2 has the highest hardness, HV1537, and flexural strength, 589 MPa while these with the addition of BN have the worse mechanical properties. By XRD and SEM micrographs, it is found that MoS2 added into Al2O3/TiC/MoS2 ceramic composites decomposes and the matrix has many pores; BN added into Al2O3/TiC/BN ceramic composites reacts with Al2O3 to form AIN, which leads to many cracks in Al2O3/TiC/BN ceramic composites and decrease of flexural strength and hardness; CaF2 added into Al2O3/TiC/CaF2 ceramic composites has no reaction and the size of crystalline grains is even, and the matrix of the Al2O3/TiC/CaF2 ceramic is net shaped which contributes to improving the bending strength of the material.