SPS reaction sintered boron carbide ceramics
Release time：2021/03/17 Author：
Meiqi
Abstract: Boron carbide ceramic materials were prepared by reaction sintering of boron powder and toner by spark plasma sintering (SPS) technology. The effects of different SPS sintering temperatures on the density phase and microstructure of boron carbide ceramics were studied. When the sintering temperature was 1700, the relative density of the materials was 90%.Sintering temperature increased to 1900, the density of 95%, lower than the traditional sintering method achieved the same reaction sintering density when the sintering temperature of boron carbide ceramic materials with fine microstructure grains, transmission electron microscopy (sem) observed with light and dark stripes in grain, analysts say the streaks are some exist in the grain layer caused by the fault surface defects such as twin preparation after a series of experiments, the chemical composition of boron carbide ceramics deviation of reaction sintering experience curve, using the curve by changing the boron/carbon ratio of raw materials, can effectively control the chemical composition of sintered bodyUsing X-ray diffraction (XRD) and electron energy spectrum (XPS) analysis the reaction sintering raw material composition of boron carbide ceramic phase and the influence of each atom in the chemical environment When the boron/carbon ratio in raw material increased, reaction sintering molecules of the boron carbide carbon atom has been replaced with the boron atoms, the main chain of the crystal lattice and the B - B keys on the icosahedron share has increased, and the C - B and C - C keys disappear, its share of declineThrough the analysis of X-ray diffraction spectra and Rietveld full spectrum fitting analysis, precise lattice constant of the material, found that the reaction sintering cell structure of the boron carbide favor B_ (13) the theory structure of C_2 The main phase of B_4C and B_ (13) with a variety of testing methods of reaction sintering (C_2 structure of boron carbide ceramics are analyzed and characterized, and its sintering densification mechanism is discussed, and points out that the reaction sintering includes four processes: the mixture of contact between reactants and generate surface effect;Chemical reaction;Formation of new phases;Correction of structural defects in crystal growth.
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