Silicon nitride whisker reinforced magnesium aluminate spinel breathable refractory material and preparation method thereof

Abstract

The invention relates to a silicon nitride whisker reinforced magnesium aluminate spinel breathable refractory material and a preparation method thereof. The method comprises the following steps: taking 15-21 wt%, 30-39 wt% and 17-24 wt% of modified spherical porous magnesia-alumina spinel ceramic particles I, II and III as aggregates, and taking 2-4 wt% of magnesia fine powder, 3-6 wt% of corundum fine powder, 3-8 wt% of simple substance silicon powder and 8-20 wt% of spinel fine powder as substrates; firstly, placing the aggregates into a stirrer for stirring, adding a catalyst accounting for 0.1-0.5 wt% of the sum of the mass of the aggregates and the substrates, stirring, adding sulfurous acid paper pulp waste liquor accounting for 3-7 wt% of the sum of the mass of the aggregate and the matrix, and stirring;adding the substrates, stirring, forming, drying, preserving heat in theN2atmosphere at 1400-1600 DEG C, and cooling to obtain the silicon nitride whisker reinforced magnesia-alumina spinel breathable refractory material. The resource utilization rate is high, the microstructure is controllable, and the prepared product is uniform and stable in ventilation, high in strength, excellent in erosion resistance and excellent in thermal shock stability.

Description

technical field [0001] The invention belongs to the technical field of magnesium aluminum spinel breathable refractory materials. In particular, it relates to a silicon nitride whisker-reinforced magnesium-aluminum spinel gas-permeable refractory material and a preparation method thereof. Background technique [0002] Aluminum and its alloys are widely used in my country's manufacturing industry, and are the main structural materials in industries such as aerospace, automobile, rail transit and construction. However, with the rapid development of these industries, the requirements for aluminum and its alloy parts are increasing higher. Inclusions such as hydrogen and oxides are important factors affecting the quality of aluminum and its aluminum alloys. The bubble flotation method is to use breathable refractory materials to blow nitrogen into the melt of aluminum and its alloys to remove H in the melt. 2 Important methods such as gas and oxide inclusions, homogenization t...

AI Technical Summary

Problems solved by technology

For example, the patented technology of "breathable refractory material for aluminum refining and its preparation method" (CN200610018089.X) uses dense calcium hexaaluminate material, tabular corundum, fused white corundum and chromium oxide green as the main raw materials. A breathable refractory material for aluminum refining is produced, but the particles in the product are dense, and the gas can only breathe through the pores between the particles. At the same time, it is difficult to form a neck connection between dense aggregates, which limits the strength and thermal shock stability of the product

[0004] Another example is the patented technology of "a dispersion-type air-permeable brick and bottom-blown inert gas purification method for aluminum alloy melt" (CN200610110580.5), which uses SiC, pore-forming agent, additives and binders as the main raw materials, and is then dried, roasted and foamed A kind of dispersed "SiN-SiC" air permeable brick is produced by forming, but the uneven distribution of the pore forming agent in the product can easily lead to uneven distribution of pores, and the foaming preparation process leads to large pores and uneven pores. It will lead to large size and uneven distribution of blown bubbles, which limits the effective adsorption of bubbles to inclusions

[0005] Another example is the literature technology (Zhou Yuhuan, Liu Huili, Lu Jiyan. Application of breathable bricks in the aluminum alloy refining process. Non-ferrous metal processing, 2015.44 (1): 23-25.) The breathable bricks prepared by alumina-chromium refractory materials are used. However, the material is easily eroded and penetrated by molten aluminum, which limits the service life of the breathable refractory material

[0006] Therefore, the existing air-permeable refractory materials for refining aluminum and its alloys still have technical defects such as large pore size, uneven distribution of pores, low strength and poor corrosion resistance and permeability.