固相烧结碳化硅陶瓷具有很高的机械强度，且生产工艺简单，但经常存在原料粒径过大，分布不均，小颗粒团聚，影响烧结体的最终性能。水基浆料喷雾造粒可有效解决这些问题，且具有安全性好，成本低，设备简单等优势，近年来在特种陶瓷制备行业颇受青睐。本研究采用不同粒径α和β混合相粉体作为原料，用水基浆料喷雾造粒手段获得造粒粉料后进行干法成型和无压烧结。在该过程中，本研究优化了碳化硅混合粉体固相烧结配方；考察了影响最终烧结体致密度的各个因素及其作用机理，确定了各环节最优工艺参数，并对烧结中出现的异常现象做出解释。 研究表明，实验所制备的浆料呈现剪切稀化特性，属于非牛顿假塑性流体；浆料粘度主要受到固相含量和PH值的影响。当分散剂PEG+TMAH添加量为1%+0.2wt%，浆料固含量为50~55%，PH值为9~9.5时，在12r/min剪切速率下，浆料粘度为400~500mpa·s，喷雾造粒效率为5~6kg/h，得粉率80%以上。最佳参数为：热风进口温度280~290℃，出口温度90~100℃，雾化器转速18000~20000r/min，蠕动泵进料转速65~70r/min。造粒粉料流动性与原粉相比有了很大提高，松装密度从0.53~0.55g/cm3上升到0.905g/cm3，休止角从48~51°下降到23°；造粒粉料粒径分布在200~120目（即75μm~120μm）之间的颗粒均占了全部粉料的80%以上，粉料分布范围较窄。 粉料干法成型时，在70MPa压力下，不同粘结剂含量造粒粉料均可以完全破碎，在110~120MPa下素坯密度达到最大2.016g/cm3，过大压力导致坯体分层。 本实验采用1μmB4C代替3μmB4C后，达到同程度的致密化烧结时，烧结温度从2065℃下降到2000℃，保温时间缩短为30min，且B4C最佳添加量为1~1.5wt%。将不同粒径β-SiC添加到1μm的α-SiC作为原料，进行烧结试验，结果当β-SiC粒径为1μm时，最终的烧结体密度最高达到3.15g/cm3，维氏硬度为23.98GPa，断裂韧性为4.44MPa·m1/2。最终得出，在α-SiC中添加合理粒径的β-SiC有利于烧结体晶粒的细化和硬度提高，但对其韧性的改善效果并不明显。在烧结温度上升到为1400℃时通入Ar气，气氛压力0.04MPa，可防止烧结时烧结体表面石墨层的形成。

Solid-phase sintered silicon carbide ceramics has high mechanical strength and simple production process.But the following problems are existing:large particle size of the raw material, small particle's agglomeration and uneven distribution, all of these will influence the performance of sintered bodies. Water-based slurry spray granulation can not only effectively solve these problems, but also has excellent security, low cost, simple equipment, and other advantages, so it become popular in the Special Ceramics industry in recent years. In this study,using different particle size α and β mixed phase powder as raw materials,the materials will be scattered in deionized water, after wet grinding ball into a homogeneous paste, and spray granulation and dry forming, finally pressureless sintering.In the process of this study optimize the silicon carbide mixed powder solid-phase sintering formula; examine the various factors that affect the final sintered body density and its mechanism, identify process parameters of every step, and explain the abnormal phenomenon in sintering process. The study showed that the slurry prepared by the experiments showing the shear-thinning properties, belonging to the non-Newtonian pseudoplastic fluid; slurry viscosity is mainly affected by the solid content and the PH value.When contain 1%PEG+0.2wt% TMAH and solid content of 50~55%, PH value of 9~9.5in slurry,under 12r/min shear rate, the viscosity is 400~500mpa·s, and spray granulation efficiency is 5~6kg/h, have yield more than 80%. The best parameters is: hot air inlet temperature of 280~290℃,90~100℃outlet temperature, atomizer speed 18000~20000r/min,peristaltic pump feed speed of 65~70r/min. Then the fluidity of Granulation powder compared to the original powder has been greatly improved, the bulk density increased from 0.53~0.55g/cm3 to 0.905g/cm3, angle of repose decrease from 48~51°to 23°；The particles which size distribution between 200~120 mesh (75μm~120μm) are more than 80 percent of all the powder, the size distribution of a narrow range. In molding process,the granulation powder of different binder content can be completely broken under 70MPa pressure,when pressure under 110~120MPa ,the density of green body achieve maximum 2.016 g/cm3 , too much pressure leads to a green body layered. In this study, after 1μmB4C insteading 3μmB4C, when reaching the same degree of densification sintering, the sintering temperature decreased from 2065℃to 2000℃, holding time is reduced for 30min, and the the B4C best dosage is 1~1.5wt%. Different size β-SiC is added to 1 μm α-SiC as a raw material, sintering test results shows that when the β-SiC particle size is 1μm, the final sintered density up to 3.15g/cm3, the Vickers hardness of 23.98GPa,fracture toughness of 4.44MPa·m1/2. The finally conclusion is that a reasonable particle size of β-SiC added into α-SiC is conducive to refine of sintered grain and increase hardness, but improvement of its toughness is not obvious.When the sintering temperature rise to 1400℃, passing over Ar gas, and the atmosphere pressure for 0.04 MPa, can prevent the formation of graphite layers in sintered body surface.