Thermo-structural analysis of sol-gel route based yttria stabilized tetragonal zirconia (YSTZ) powders for thermal barrier applications

摘要

Yttria stabilized zirconia (YSZ) powders have been synthesized via sol-gel solution route in order to obtain thermal barrier coatings (TBCs) from sol-gel. Conventional method of preparation of sol and gel has been used for coating and thermal analysis respectively. Prepared gel is heated at 150 degrees C for 3h and 250 degrees C for 3 h and thermal analysis of powder is carried out. At this stage two routes are followed to get the sintered powder. Sintered powder-1 is obtained after heat treatment of 800 degrees C for 3 h and sintered powder-2 is obtained by heat treatment at 1300 degrees C for 3 h. Thermal analysis of both gel and dried powder at 150 degrees C for 3 h show the exothermic process of 187.5 degrees C, indicating the start of the nucleation process of crystallization of the tetragonal phase of YSZ powder. Sintered powder obtained after heating the powder at 1300 degrees C for 3 h is found to have more identical grain size distribution of YSZ powder in comparison to powder sintered at 800 degrees C for 3 h. The total mass loss of gel and powder obtained by drying gel at 150 degrees C for 3 h is found to be 31.4 and 31.0 respectively, indicating amorphous behavior at this stage.