High-temperature refractory materials refer to materials that can be used for a long time in a high-temperature environment without obvious damage. These materials are widely used in high-temperature furnaces, kilns, reactors and other equipment in the steel, metallurgy, power, chemical and other industries. The performance requirements of high-temperature refractory materials are directly related to the efficiency and safety of industrial production. This article will explore the performance requirements of high-temperature refractory materials from multiple aspects.

1. Refractoriness
Refractory is one of the most basic properties of high-temperature refractory materials. It refers to the maximum temperature that the material can withstand under specified conditions. The higher the refractoriness, the stronger the ability of the material to maintain structural stability in a high-temperature environment. The refractoriness of refractory materials is usually expressed in terms of melting point. For example, common high-temperature refractories such as bauxite and high-alumina refractory bricks have a high refractoriness and can withstand temperatures above 1500°C, while some special high-temperature synthetic materials, such as silicon carbide (SiC) and aluminum carbide (Al4C3), can reach a refractoriness of 2000°C or even higher.

2. High temperature strength
High temperature strength refers to the maximum stress that a refractory can withstand under high temperature without cracking or plastic deformation. The strength of refractory materials is crucial under high temperature conditions, especially in the metallurgical industry, where the load under high temperature is often extremely large. In order to ensure the stable operation of equipment under high temperature, refractory materials need to have sufficient high temperature strength to withstand the physical pressure and chemical reaction pressure inside the furnace body.

Generally, the high temperature strength of refractory materials is closely related to the composition, sintering degree and microstructure of the material. Taking bauxite as an example, at high temperature, its strength will decrease slightly with the increase of temperature, but if the material contains a high bauxite content, it usually maintains good high temperature strength.

3. Thermal shock resistance
Thermal shock resistance refers to the ability of a material to maintain its structural integrity under sudden temperature changes. In high temperature environments, refractory materials often experience rapid temperature rise and fall. If the thermal shock resistance of the material is not good, cracks may appear due to uneven thermal expansion, or even cause rupture. In order to improve the thermal shock resistance of refractory materials, raw materials with good thermal stability and uniform thermal conductivity are usually selected, and the microstructure of the material is improved through reasonable formula design.

For example, materials such as silica bricks and clay bricks are often added with some trace elements or chemicals during design to enhance their thermal shock resistance. In metallurgical furnaces, refractory materials have to withstand high temperature changes from room temperature to thousands of degrees, so their thermal shock resistance is crucial.

4. Chemical stability and corrosion resistance
High-temperature refractory materials also need to have good chemical stability and corrosion resistance. The high-temperature reaction environment in metallurgy, petrochemical, power and other industries often contains various chemicals, such as acids, alkalis, oxidants, reducing agents, etc. These chemicals are easy to react with refractory materials, causing corrosion or damage to the materials.

For example, during the smelting process, refractory materials will react with metals, slags and gases in the furnace to produce chemical corrosion reactions. Therefore, refractory materials must have good chemical stability and be able to resist the erosion of these corrosive media. Materials such as bauxite, magnesia bricks, and zirconium bricks are often used in high-temperature reaction environments due to their excellent chemical stability.

5. Thermal conductivity and thermal insulation performance
Thermal conductivity is an important indicator for measuring the thermal conductivity of materials. The thermal conductivity of high-temperature refractory materials is generally low to avoid rapid heat conduction and ensure the energy efficiency of equipment at high temperatures. In order to improve the thermal insulation performance of refractory materials, it is usually necessary to use materials with lower density and higher porosity. For example, materials such as ceramic fibers and lightweight refractory bricks can effectively isolate heat and reduce heat loss due to their low density and high porosity.

In addition, while ensuring good thermal insulation performance, high-temperature refractory materials must also have appropriate thermal conductivity to ensure that they are not overloaded by heat loads and cause heat loss or equipment damage.

6. Anti-oxidation and chemical corrosion resistance
Refractory materials need to have strong anti-oxidation ability, especially in high-temperature oxygen environments, and can resist oxidation without being destroyed. In many industrial applications, especially in the metallurgical industry, the furnace atmosphere is full of oxygen and other harmful gases. Therefore, refractory materials need to have excellent anti-oxidation properties.

For example, magnesium-aluminum alloy materials and silicon-aluminum materials have excellent oxidation resistance at high temperatures and are widely used in high-temperature reactors and furnace facilities, and can withstand oxygen erosion in the atmosphere.

7. Permeability resistance
In some high-temperature environments, the permeability of liquids or gases may cause damage to the internal structure of the material, thereby affecting its service life. In order to improve the service life of high-temperature refractory materials, the material needs to have good permeability resistance. This is usually achieved by adjusting the particle ratio of the material and increasing the density of the material.

For example, in some high-temperature furnaces, due to the highly corrosive environment in which the material is used, the refractory material needs to be optimized by optimizing the microstructure and improving the permeability resistance to prevent the penetration of harmful gases or liquids.

Conclusion
In summary, the performance requirements of high-temperature refractory materials mainly include refractoriness, high-temperature strength, thermal shock resistance, chemical stability, corrosion resistance, thermal conductivity and thermal insulation performance. In practical applications, the performance of refractory materials directly affects the stability and safety of industrial production. Therefore, selecting suitable refractory materials and optimizing their performance can greatly improve the efficiency of industrial production, reduce production costs, and ensure the long-term stable operation of equipment.