Magnesium aluminum spinel resistant refractory material is a refractory material consisting of magnesium and magnesium oxide content (mass score) of not less than 20%. Due to the large range of changes in the content of Al₂O ₃ and MgO, we will use Al₂O₃ and MgO and MgO The refractory material for the main chemical ingredients is collectively referred to as magnesium aluminum refractory materials.
MgAl2O4 is the core object of magnesium aluminum refractory material. It belongs to a typical spinel structure. It has excellent performance such as high melting points, low thermal expansion coefficients, good mechanical strength and slag resistance.
There are certain defects using traditional craftsmanship (that is, large particles of MgO and Al₂O ₃ to prepare MgAL₂O ₄ after high temperature sintering), which leads to the following difficulties in the existence of magnesium and aluminum refractory materials: on the one hand, the sintering performance is poor, because the process of spinel formation will accompany 5 with 5 %To 8%of the volume expansion effect, there are a large number of initial cracks and micro -pores in the micro structure, which is difficult to prepare dense products; on the other hand, the mechanical properties are poor. Cracks can improve its heat shock performance to a certain extent, but as the content of large particles spinels increases, micro -crack defects and strength loss increase, it is difficult to meet the development of high temperature industries. Nano -technology is an effective solution to the effective solution of excellent sintering performance, mechanical properties and anti -seismic performance magnesium aluminum refractory materials.
The use of nano -technology to improve the sintering performance, mechanical performance, and thermal shock resistance of magnesium and aluminum refractory materials, mainly in two aspects: First, nanoparticles have surface effects and small size effects, which can reduce the contact points between MgO and Al₂O₃, Shorten the diffusion distance between the particles, promote product sintering, and improve the intensity of mechanics. Second, the relationship between regulating the length of the micro -crack and the size of the grain is the key to controlling the relationship between sintering performance, mechanical performance, and thermal seismic performance of magnesium aluminum refractory material. When the grain size is greater than the critical grain size, cracks will appear inside the material, and the crack length increases with the size of the grain. The grain size reaches a certain degree. The intensity is almost lost. For the use of nano -level raw materials, the length and quantity of the micro -cracks inside the material can be reduced. Nano -granular particles are easier to buffer the heat stress and improve the strength and toughness of the material.
