| TiB2-BN composite has a great application potential owing to its machining property and designability of resistivity. But many problems such as sintering difficulty, instability and inhomogeneous etc still exist. This paper starts with the heat transfer problem of newest sintering technology, using the method of calculation, simulation and experiment to study the temperature distribution in sintering process, using the percolation theory and the orthogonal experimental design method to optimize the major factors influencing the sintering process, reasons for the deliquescence of the composite were studied. The thermal fatigue problems of sample under the imitation operating mode condition were analysed.The paper proves that sparking has occurred in the samples during the initial stage of sintering based on the sudden temperature rise in the experiment and the two mechanisms for the conversion from electricity to heat. In the initial stage of sintering, when certain sintering conditions are satisfied, the result of the measurement shows that there is a sudden temperature rise. This high energy conversion shows the existence of sparking. This result is further proved by the measurement of the vacuum level and the sample shrinkage. On the other hand, there is no sparking, if the sintering sample is insulant and there is no sudden temperature rise, either.In the middle stage of sintering, the heat of the sample comes chiefly from the punches. The result of numerical calculation shows that the direction of the thermal current is consistent with that of the pressure. Whether the sample is insulating or conducting, the direction of thermal current is always from the punch to the sample. The temperature distribution forms closed ring isotherm in insulating sample, and forms gradient isotherm in electric conducting sample. The temperature distribution of radial appears monotone function in electric conducting sample, and appears undulation in insulating sample.The paper further reveals that there is a big temperature gradient in the final stage of Spark Plasma Sintering TiB2-BN and its size is directly related to electric and heat conductivities of the material. In the final stage of the sintering, this paper also works on discovering two-dimension steady-state temperature distribution in sample. The results are: at the radial and the axial directions ofsample, the temperature distributing assumes parabola. Focusing on the radial temperature distribution problem, the temperature difference between a point of symmetry plane and the center of sample is: It points out that as long as the sintering sample is an electric conducting material, the existence of temperature difference inside sample and the mould is unavoidable and the center temperature is the highest. Owing to different thermal conductivity and heat release rate, the temperature differences that exist in different samples are different, but none of them equals to zero. If the sample is insulant, it is possible to reach zero temperature difference sintering with zero heat release rate.The measuring results of temperature field in final stage of sintering are as the following: With high sintering temperature and low thermal conductivity, there is high temperature gradient in TiB2-BN sample, the biggest temperature difference reaches 450, (at sintering temperature 1700C ) . If the sample is metal Cu, the temperature difference is small, the temperature difference is less than 50C (at sintering temperature 900 , ) . If the sample is BN, the higher of the heat-up rate, the bigger of the temperature difference, the temperature difference can reach 220 C(at sintering temperature 1300C, 8C/s), and less than 50C (at sintering temperature 1100C, 1.8C/s) .Depending on heat transfer from the die and the punch the temperature difference is adjustable. The experiment results match with the calculated results.The percolation model that is compatible with the SPS TiB2-BN composite can be established by using the theory of percolation to explain the conducti...
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