Solid-phase-sintered silicon carbide article and preparation method thereof

A method for preparing a solid-phase-sintered silicon carbide article, comprising the following steps:

• Step S1, mixing a micron-scale silicon carbide powder with a particle size of 3-10 μm with a boron-containing sintering aid and wet grinding to obtain a slurry with a particle size of 0.4-0.8 μm;
• Step S2, adding a water-soluble carbon black and a binder to the slurry, stirring evenly, and spray granulating to obtain a granulated powder of silicon carbide;
• Step S3, mixing the granulated powder of silicon carbide with a plasticizer evenly, adding a lubricant and water, and stirring evenly to obtain a wet powder;
• Step S4, ageing the wet powder to obtain an aged material;
• and
• Step S5, subjecting the aged material to pugging, extruding, drying and heating;
• wherein the drying comprises a primary drying and a secondary drying, the primary drying is far-infrared drying, a temperature for the primary drying is 80-100° C., a material conveying speed is 0.5-1 m/min, the secondary drying is hot air drying, a temperature for the secondary drying is 120-150° C., and a time for the secondary drying is 15-20 h.

A method for preparing a solid-phase-sintered silicon carbide article, comprising the following steps:

• Step S1, mixing a micron-scale silicon carbide powder with a particle size of 3-10 μm with a boron-containing sintering aid and wet grinding to obtain a slurry with a particle size of 0.4-0.8 μm;
• Step S2, adding a water-soluble carbon black and a binder to the slurry, stirring evenly, and spray granulating to obtain a granulated powder of silicon carbide;
• Step S3, mixing the granulated powder of silicon carbide with a plasticizer evenly, adding a lubricant and water, and stirring evenly to obtain a wet powder;
• Step S4, ageing the wet powder to obtain an aged material;
• and
• Step S5, subjecting the aged material to pugging, extruding, drying and heating;
• wherein the heating comprises the following steps:
• performing debonding by heating the aged material to 600-900° C. and holding for 1-3 h;
• performing carbothermal reduction by heating the aged material after the debonding to 1400-1450° C., then to 1550-1600° C. at a rate of 0.5-2° C./min, and holding for 0.5-2 h at a temperature of 1550-1600° C.;
• and
• performing sintering at high temperature by heating the aged material after the carbothermal reduction to 1950-2150° C., and holding for 2-3 h.