A self-healing and anti-oxidation silicon carbide castable and preparation method thereof

Abstract

The invention relates to a self-repair anti-oxidation silicon carbide casting material and a preparation method thereof. According to the technical solution, 75-95 wt% of silicon carbide, 1-8 wt% of carbon black, 0.1-8 wt% of monatomic silicon powder, 0.5-6 wt% of silica powder and 0.1-4 wt% of monatomic zirconium are used as raw materials, and a water reducing agent accounting for 0.1-0.3 wt% of the raw materials is added into the raw materials and mixed uniformly, so as to obtain a premix; and then silica sol accounting for 5-15 wt% of the raw materials is added into the premix, and the silica sol and the premix are stirred uniformly to obtain the self-repair anti-oxidation silicon carbide casting material. The prepared self-repair anti-oxidation silicon carbide casting material has the characteristics of excellent medium- and high-temperature mechanical properties, high thermal conductivity, strong oxidation resistance, good thermal shock stability, long service life, energy conservation and environment friendliness.

Description

technical field [0001] The invention belongs to the field of castable technology. In particular, it relates to a self-repairing and anti-oxidation silicon carbide castable and a preparation method thereof. Background technique [0002] SiC has high melting point, high hardness, high thermal conductivity and good slag corrosion resistance, and is widely used in iron and steel smelting, nonferrous metallurgy, waste incineration and ceramics industry. However, the fatal weakness of SiC material is that it is easy to oxidize at high temperature, and SiO is formed on the surface of SiC after oxidation. 2 Oxide film, SiO 2 There is a large gap between the expansion coefficient of the oxide film and the SiC substrate, and cracks will occur during the hot and cold cycle, and too much SiO 2 It is not good for the high temperature performance of SiC material. The researchers prepared B on the surface of SiC 2 o 3 coating to improve the oxidation resistance of SiC, under high tem...

AI Technical Summary

Problems solved by technology

However, the fatal weakness of SiC material is that it is easy to oxidize at high temperature, and SiO is formed on the surface of SiC after oxidation. 2 Oxide film, SiO 2 There is a large gap between the expansion coefficient of the oxide film and the SiC substrate, and cracks will occur during the hot and cold cycle, and too much SiO 2 Detrimental to the high temperature performance of SiC materials

The researchers prepared B on the surface of SiC 2 o 3 coating to improve the oxidation resistance of SiC, under high temperature conditions, the B after melting 2 o 3 Good fluidity, can fill pores, prevent O 2 Diffusion, although the oxidation resistance is improved, but when the temperature is higher than 1100 ° C, B 2 o 3 Severely volatile, can not play the role of anti-oxidation

"A castable for high-temperature waste incinerator and its preparation method" (CN201510721132.8) patent technology, introduces ferric nitrate into SiC castable, obtains Fe after reduction, and uses Fe as antioxidant, although SiC castable for waste incinerator is improved The oxidation resistance of the material, but the introduction of Fe increases the impurities of the refractory material, increases the amount of liquid phase at high temperature, reduces the viscosity of the liquid phase, and is detrimental to the high temperature performance of the material

"A silicon carbide brick for waste incinerator and its preparation method" (CN201110235574.3) patented technology, adding silicon powder and aluminum powder as antioxidants, although the added silicon powder and aluminum powder can slow down the oxidation of SiC, but the oxidation The final product is still inconsistent with the expansion coefficient of the SiC matrix, which will cause material cracking