Preparation method of oxide combined SiC porous ceramic

Abstract

The invention discloses a preparation method of an oxide combined SiC porous ceramic. The oxide combined SiC porous ceramic is prepared from 75-85 wt% of SiC, 5-15 wt% of Al2O3, 2-7 wt% of SiO2, 0-5 wt% of MgO and 5-10 wt% of graphite. The method comprises the following steps: uniformly mixing the SiC and sodium carboxymethyl cellulose solution, adding the Al2O3, SiO2 and MgO, uniformly mixing, finally adding the graphite into the mixture, and uniformly mixing; carrying out two-way pressurization on the mixture to form a billet; and drying the billet, and sintering at 1350-1550 DEG C in an air atmosphere. The sintering temperature can be properly enhanced to lower the addition amount of the binder, and the pore size distribution is uniform due to the two-way pressurization. Almost all the oxides are converted into compounds which are beneficial to enhancing the material properties, so that the prepared porous ceramics has favorable high-temperature creep resistance.

Description

[0001] technical field [0002] The invention relates to a method for preparing porous ceramics for filtering, in particular to a method for preparing oxide-bonded SiC porous ceramics. Background technique [0003] In the field of clean coal combustion technology, the treatment of high-temperature dust gas is a difficult problem. Filtration and dust removal is an ideal dust removal method, but the selection of filter materials is a key issue. my country's filter material is mainly glass fiber, but its use temperature is low, generally lower than 400°C. In a high temperature use environment, it needs to be mixed with cold air to cool down before filtering, which reduces the filtration efficiency. In order to solve the above problems, people invented oxide porous ceramics, but the alkali resistance of oxide porous ceramics is poor. Ceramics are widely used in filter materials due to their good heat resistance, good acid and alkali corrosion resistance, high mechanical str...

AI Technical Summary

Problems solved by technology

Pores are formed by special particle size distribution stacking combined with organic pore-forming agent, formed by spray granulation isostatic pressing, pressure 20-200MPa, argon protection sintering, sintering temperature 2000-2300℃, pressure 0.1-0.3MPa, SiC raw material The purity is 98-99%, which needs to be purified. The average pore size is 30-100μm, the porosity is 20-40%, and the bending strength is 15-35MPa. The advantage of the invention is that the SiC content is as high as 98.5%, does not contain binders, and has stable mechanical strength and structure. Excellent performance, which reduces the performance degradation of the material in the working environment, and recrystallized SiC sintering does not shrink, can obtain accurate product size and is easy to control the pore size and pore size distribution range of the opening, but due to the high molding temperature, so , the process control is complicated, and the manufacturing cost is high

[0006] The control of SiC fine powder is a difficult problem today, and the cost of the above-mentioned several technologies is high, which is not conducive to the control of industrial production costs