Plastic phase forming: The metal will slip in the lattice under stress and has plastic characteristics. Introducing it into the refractory, it will play plastic forming characteristics during the forming process compared to the hard inorganic material particles, making the density of the raw billet prepared under the same forming pressure higher than that of the specimen without added metal.
Promoting sintering: The sintering effect of metals on refractory materials can be attributed to two factors: first, the plastic phase formed by the introduction of metals can increase the density of the billet, shorten the distance between particles, and reduce the energy required for diffusion and mass transfer during the firing process; second, the melting point of metals is generally lower than that of refractory materials, and they can generate the liquid phase at a lower temperature. accelerates the migration rate of atoms and the shrinkage of the billet, which promotes the densification process of sintering.
Toughness improvement: Metals can improve the toughness of composite materials through mechanisms such as crack bridging, crack deflection and crack barrier, among which crack bridging is the most effective toughening mechanism, i.e., when the crack extends to the interface between the metallic material and the matrix material, due to the ductility of the metallic particles, the crack elongates the force, which will apply a bridging stress on the upper and lower surfaces of the crack, which on the one hand can prevent the crack from opening and reduce the crack On the one hand, it can prevent the crack from opening and reduce the strength factor of the crack tip, and on the other hand, it can deform plastically with the opening of the crack, which consumes the energy of the crack tip and toughens it.
Oxidation resistance: Carbon composite refractories have superior thermal shock resistance and slag resistance due to the presence of carbon, but have the defect of easy oxidation, and once the carbon is oxidized, its advantages will be lost. In order to give full play to the advantages of carbon composite refractories, the oxidation resistance is often improved by adding appropriate additives. Metals are used as antioxidants in refractories due to their active properties and easy reaction with O2 and CO. Al, Si, Mg and corresponding alloys are commonly used as antioxidants.
From the above, it can be seen that the addition of metals to refractory materials has a positive effect on the mechanical properties and oxidation resistance of refractory materials, which bodes well for their promising applications in refractory materials. With the continuous development of science and technology and breakthroughs in the field of science, the performance of metal composite refractories will be optimized and their applications will be further expanded.
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