Method for preparing silicon nitride compound silicon carbide ceramic from crystalline silicon cutting waste materials

Abstract

The invention discloses a method for preparing a silicon nitride compound silicon carbide ceramic from crystalline silicon cutting waste materials, belonging to the technical field of ceramic technologies and comprehensive utilization of secondary resources. According to the method, high-purity Si powder in diamond linear cutting crystalline silicon waste materials and SiC micro powder which is easily collected from multi-thread linear cutting crystalline silicon waste materials are used and are subjected to a mixed nitrogenization reaction and normal pressure sintering to prepare the silicon nitride combined silicon carbide ceramic. The method has great effects on reducing the production cost, using the secondary resources, improving the environment, controlling the product quality and improving the pull rate of ceramic products, and the silicon nitride compound silicon carbide ceramic is particularly suitable to be used as a silicon nitride combined silicon carbide compound material for low pressure casting of lift pipes.

Description

technical field [0001] The invention belongs to the technical field of ceramic technology and comprehensive utilization of secondary resources, in particular to a method for preparing silicon nitride composite silicon carbide ceramics from crystalline silicon cutting waste materials. technical background [0002] Si 3 N 4 And SiC are the preferred materials in high temperature engineering ceramics due to their chemical stability, thermal shock resistance and excellent creep resistance. Si 3 N 4 Ceramics have excellent flexural strength and hardness at room temperature, but at high temperatures due to Si 3 N 4 Ceramics are usually sintered in liquid phase, which leads to high-temperature softening of the grain boundary glass phase, making its high-temperature strength inferior to that of SiC ceramics. In order to take advantage of the respective advantages of the two ceramics, Si 3 N 4 Combined with SiC composite phase ceramics (SNBSC for short). SNBSC ceramics are d...

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Problems solved by technology

Patents 201010281668.X and 201010281670.7 mixed silicon ingot wire cutting waste, aluminum nitride powder, silicon nitride powder, silicon dioxide powder and lithium glass powder in a certain proportion and fired them into a ceramic catheter in a nitrogen atmosphere; but the nitrogen in the composition Aluminum powder is a relatively expensive raw material, and the proportion of use is relatively large (8-15wt%), which affects the economics of its large-scale production of ceramic catheters; at the same time, although the addition of lithium glass powder reduces the sintering temperature, but due to the lithium glass powder When the powder is used at high temperature in the ceramic catheter, it is prone to high-temperature creep, resulting in a decrease in high-temperature mechanical properties, so the practicability of these two patents is limited

[0005] Using the high-purity Si powder in the waste of diamond wire cutting crystalline silicon and the easily collected SiC micropowder in the waste of multi-wire cutting crystalline silicon, mixed nitriding reaction and sintering at normal pressure to prepare silicon nitride bonded silicon carbide ceramics. No report

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