ZrO2-Al2TiO5 composite materials with high bending strength and good thermal shock resistance expansion were prepared using partially stabilized zirconia (Y-PSZ) powders coated with Al2TiO5 by co-precipitation method. The effects of Al2TiO5 content on the sintering properties, phase composition, microstructure and thermal shock resistance of the zirconia ceramic were investigated.The results show that the apparent porosity of the samples decreased and their bending strength increased with the content of aluminum titanate increasing from 0 to 8 wt%. The samples with 5 and 8 wt% aluminum titanate addtion have excellent thermal shock resistance. The results showed that the addtion of aluminum titanate could enhance the mechanical strength and improve the thermal shock resistance of zirconia ceramic. The XRD and SEM analysis results indicated that the propriety improvement is relative with the change of the microstructure and the increase of tetragonal ZrO2 phase in the composites.
β-sialon-ZrO2composites with Si5AlON7 or Si4Al2O2N6 bonding phase were prapared in N2 atmosphere at 1550°C with Si, Al2O3, AlN and ZrO2 (Ca) as raw materials by reaction in situ pressureless sintering. Effect of Z value and content of β-sialon batch on its sintering performance, phase composition, microstructure, and thermal expansion character were investigated. Results showed that the phase of Si5AlON7 was formed in samples with β-sialon designing Z=1, and phases of Si5AlON7 and Si4Al2O2N6 were formed in samples with β-sialon designed Z=2 and β-sialon designed Z=3, respectively and Bending strength of samples increase with content of β-sialon batch. When content of β-sialon batch equals 10wt%, 15wt% and 15% respectively, the samples with β-sialon designed Z=1, Z=2, and Z=3 have lower apparent porosity, microstructure of homogeneous and compact and lower thermal expansion coefficient, respectively.
Al-ZrO2 composites were sintered in N2 atmosphere at 1000 oC, 1100 oC, 1200 oC and 1300 oC with ZrO2 and Al powders as raw materials. Formation mechanism of AlZrO and ZrAlON phases in Al-ZrO2-N2 systems were investigated by TG-DTA, XRD, SEM and EDS analyses. Results showed there existed new phases of ZrAl3O3N and AlxZr1-xO2-0.5x beside ZrO, ZrN, Al2O3, AlN and intermediate phases of Al7O3N5, Al8O3N6, ZrON, ZrON2, Zr7O8N4 in samples sintered at 1000 oC to 1300 oC. There existed process of mass transfer of ZrO2 in gas phase in samples at high temperature. Dynamics processes of ZrAl3O3N and AlxZr1-xO2-0.5x phases formed in N2 atmosphere at high temperature included contact reaction and ZrAlON sosoloid crystallization.
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