Study On In-Situ Growth Elongated Grains Cooperating With 3Y-TZP To Toughen Alumina Ceramics

This paper studied on the evolution of Al₂O₃ elongated grain doping with CAS, Nb₂O₅, MgO and 3Y-TZP under without pressing or hot pressed sintering respectively. From in-situ growth elongated grain of Al₂O₃ cooperating with second phase to toughen Al₂O₃, we firstly researched microstructure and sintering properties systematically, and detected the mechanical performance with different ingredient additives and second phase.The result shows that using CAS, Nb₂O₅, CAS+MgO and CAS+Nb₂O₅ can prompt the Al₂O₃ sintering behaviors because of liquid phase. When adding 0.6wt% CAS, the evolution elongated grain can be obtained, and the aspect ratio of grain achieved 8, relative density reached 97.2%. Using 0.4wt% CAS cooperating with 0.5wt% Nb₂O₅, the sintered properties are better than only using CAS, simultaneously, the aspect of elongate grain is over 8, and relative density is 97.8%. Using Nb₂O₅ can prompt the sintering property to a certain extent and obviously obtained equiaxed and platelet grains. CAS cooperating with MgO is avail to sintering and obtained equiaxed grain. On all accounts, Reasonable additives can be benefical to the elongated grain growth, or restrained its growth.Adding second phase can affect the microstructure of alumina ceramics. By inducing CAS+3Y-TZP, CAS+Nb₂O₅+3Y-TZP, less elongated grain growth illuminated that second phase, interfering in grain growth, but existing at second stability t-ZrO₂ and t′-ZrO₂ through phase transformations, is propitious to tougheness. In the process of ingredient diffusion, ZrO₂ is stability, and hampers Al₂O₃ grain growth in 3D space. The experiment showed that elongated grain cooperating with second phase to toughen Al₂O₃ improved the synthesis mechanical performence.According to energy spectrum analysis (EDS), Al₂O₃ ceramics ingredient was certain. Using XRD qualitatively analyzed the phases. By a great deal of dates, experiment illustrated the sintered kinetic principle, and concluded that the interface diffusing determined the sintered process. Using correlative theory, elongated grain growth mechanism was researched in step.