| Zirconia ceramics has attracted great attention in oral medicine because of its high strength,high hardness,abrasion resistance and good biocompatibility.In recent years microwave sintering of dental zirconia ceramics has become one of the mainstream sintering technologies in the field of ceramic sintering because microwave sintering has the advantages of integral heating fast heating speed and reducing sintering activation energy.However,the most important factor affecting microwave sintering is the homogeneity of ceramic materials.There are many problems in microwave sintering of dental zirconia.Therefore,it is beneficial to make better use of this technique to understand the distribution of electromagnetic field and temperature field in microwave sintering cavity.In this paper,the distribution of electromagnetic field in sintered cavity after loading cylindrical zirconia sample is simulated by three-dimensional electromagnetic field simulation software HFSS.Through the parameterized scanning of the sample position,the electromagnetic field distribution in the sample at different heights in the center of the sintering cavity was simulated,and the most uniform distribution of the electromagnetic field in the sample was found.That is to say,the position of 9.1cm is high from the bottom of the sintering cavity.The HFSS and ANSYS are combined in the WORKBENCH platform.The results of the electromagnetic field simulation are introduced into the ANSYS software to simulate the temperature field in the sintering cavity.The steady state temperature distribution and transient temperature rise curve of the sample during sintering were simulated.Zirconia ceramic blank was prepared by dry pressing and isostatic pressing.The semi-compact zirconia billets were prepared by conventional presintering and microwave pre-sintering at different pre-sintering temperature,respectively.The optimum pre-sintering temperature is determined by testing the mechanical properties of the samples.The experimental results show that the properties of conventional pre-sintered samples are better than those of microwave pre-sintered samples.Conventional pre-sintered samples were sintered by microwave and conventional sintering respectively.The optimum sintering temperature was determined by testing the properties of the samples at different sintering temperatures and SEM.The experimental results show that the properties of microwave sintered samples are better than that of conventional sintered samples,and the sintering temperature went down by 100? nearly. |
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