碳化硅材料具有良好的化学稳定性、耐磨性，耐高温、高强度和高的导热系数等优异性能，在机械、电子、能源、航天航空、空间技术以及汽车工业等领域具有广泛应用。原材料碳化硅粉体的粒径、形貌、纯度对碳化硅材料的影响至关重要，目前行业中使用的碳化硅粉体颗粒存在粒径分布不均、球形度不好、片状和条状大量存在等问题，难以制备高密度碳化硅材料，严重影响了碳化硅优异性能的发挥。因此有必要对碳化硅粉体进行整形以获得组织致密、性能优异的碳化硅陶瓷。为此，本文提出用熔盐法对SiC粉体整形的新方法，研究了熔盐种类、配比、反应温度以及保温时间等工艺参数对SiC粉体颗粒的影响。采用激光粒度分析、SEM、XRD、堆积密度、热力学计算等分析手段对整形后β-SiC粉体颗粒的形貌、大小以及成分进行表征分析，得出了相应结论： 在NaCl-KCl熔盐体系中，对β-SiC原粉（D50为37.63μm，堆积密度为1.2 g/cm3）进行整形，结果表明NaCl-KCl熔盐对原粉有细化作用，熔盐配比为1:1.2、温度800℃、保温10h时整形效果最佳，整形后得到D50为28.56μm、堆积密度为1.81 g/cm3的β-SiC粉体，粒径分布均匀，颗粒表面整洁光滑接近球形，纯度提高了6.78%。 在Na2CO3-K2CO3-CaCO3熔盐体系中，对β-SiC原粉进行整形，结果表明Na2CO3-K2CO3-CaCO3熔盐对原粉颗粒有长大作用，熔盐比例为1:1.2、温度700℃保温12h，其堆积密度增大到1.78 g/cm3，且平均粒径分布均匀，形貌平整接近球形，D50由原来的37.63μm变为42.92μm，纯度提高了7.25%，结晶性能良好。 在NaNO3-KNO3熔盐体系中，对β-SiC原粉进行整形，结果表明整形后晶粒尺寸没有明显的变化，但粒径分布较好。熔盐配比为1:1.6、温度390℃保温10h，NaNO3-KNO3熔盐使β-SiC粉体颗粒表面平整，接近球形，平均粒径分布均匀，堆积密度增大到1.72 g/cm3，纯度较高，提高了6.43%。

The silicon carbide material has excellent chemical stability, abrasion resistance, high temperature resistance, high strength and high thermal conductivity and other excellent performances, widely used in mechanical, electronics, energy, aerospace, space technology and automobile industry. The particle size, morphology, and purity of the raw silicon carbide powder are essential. The silicon carbide powder currently used in the industry has the problem of uneven distribution of particle size, poor sphericity, a large number of sheet and strip exist, it is difficult to prepare high-density silicon carbide material, which has seriously affected the excellent performance of silicon carbide materials. Therefore, it is necessary to shape the silicon carbide powder to obtain silicon carbide ceramics with tissue dense and excellent performance. Therefore, this paper puts forward a new method for shaping SiC powder by molten salt method, The influence of the processing parameters of molten salt types, molten salt ratio, reaction temperature and holding temperature time on β-SiC powder particles. By using the laser particle size analysis, SEM, XRD, bulk density and thermodynamic analysis to characterize the morphology and powder particles size and composition of the β-SiC particles after shaping. The main conclusions are as follows: In the NaCl-KCl molten salt system, β-SiC raw powder with a D50 of 37.63μm and a bulk density of 1.2g/cm3 was shaped, The results show that the NaCl-KCl molten salt have refining effect on raw powder. the refining effect is obvious under the experiment condition of the ratio 1:1.2, at the temperature of 800℃and the holding time for 10h, and get the β-SiC powders with a D50 of 28.56μm and a bulk density of 1.81g/cm3, The particle size distribution is uniform and the surface of the particles is clean and close to the spherical shape. The purity of the β-SiC powder is increased by 6.78%. In the Na2CO3-K2CO3-CaCO3 molten salt system, the β-SiC raw powder was shaped， The results show that the Na2CO3-K2CO3-CaCO3 molten salt made the β-SiC raw powder grain growth obviously under the experiment condition of the ratio 1:1.2, at the temperature of 700℃and the holding time for 12h, the bulk density is increased to 1.78g/cm3, and the average particle size distribution is uniform, the morphology is close to the spherical shape, the diameter of the medium size is increased from 37.63μm to 42.92μm, the purity is improved by 7.25%, and the crystallization performance is good. In the NaNO3-KNO3 molten salt system, the β-SiC raw powder was shaped, The results show that the grain size did not change obviously, but the particle size distribution was better under the experiment condition of the ratio of 1:1.6, at the temperature of 390℃and the holding time for 10h, The NaNO3-KNO3 molten salt makes the surface of β-SiC powder smooth and nearly spherical, particle size distribution is uniform and the bulk density is increased to 1.72g/cm3, the purity is higher, increased by 6.43%.