| In this paper, the attempt was made in SiC nano-particle reinforcing Al2O3-ZrO2. The methods of dispersion, molding, sintering were investigated in detail for composites, and the mechanisms of strengthening and toughening were studied. PEG and PMAA-NH4 were used to disperse SiC and Si3N4 nano-particles in water and alcohol. The results showed that the high dispersion and stable suspension were obtained as the addition of PMAA-NH4 being 0.3wt% and pH value 9~10. The electrosteric stabilization of PMAA-NH4 play a important role in dispersion.. The physical properties were measured using X ray diffraction analyzing, SEM observing, fracture toughness and fracture strength measuring, micro-hardening and density detection etc.The results display that the relative densities are above 98% for all the samples, especially reaches 99.8% for the sample added 2vol% SiC nano-particles. The maximum of t- ZrO2 contents reaches 50.5vol% as no addition of SiC, and it declines to 22.4vol% as 2vol% SiC added. The restriction around ZrO2 grain is relaxed due to addition of SiC.As SiC content is 2vol%, the bending strength, 629.6MPa ,is higher than that of sample added no SiC, 593.8Mpa. However, the latter toughness, 6.01 MPa(m1/2, is lower than the former, 6.69MPa(m1/2. The SiC in the composite reduces the restriction around ZrO2 particles, leading to the decrease of t-ZrO2 retention at room temperature and toughness. Otherwise, SiC can strengthen the samples by its pinpoint effect.The results also showed that the hardness of samples rise with the increase of SiC, but the densities decline. The observation of fracture section displayed the fracture model is transgranular. |
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