What is the performance of wear-resistant refractory bricks at different temperatures?

The performance of wear-resistant refractory bricks shows significant differences at different temperatures, mainly influenced by material composition, crystal structure, and physical and chemical changes caused by temperature changes. The following is an analysis of the performance and mechanism of different types of wear-resistant refractory bricks in key temperature ranges:

1、 Low temperature range (normal temperature~700 ℃)

High alumina bricks and clay bricks

Wear resistance enhancement: Below 700 ℃, the wear resistance of high alumina bricks decreases with increasing temperature, and brittleness increases due to an increase in elastic modulus.

Clay bricks have stable wear resistance in low temperature zones because their crystal structure has not undergone significant changes.

Strength variation: Metal materials (such as steel fiber-reinforced bricks) have increased strength at low temperatures, but decreased plasticity, and attention should be paid to the risk of brittle fracture.

Silicon carbide brick

Outstanding stability: Silicon carbide (SiC) has high hardness (Mohs 9.5), almost unaffected wear resistance at low temperatures, high thermal conductivity, and is suitable for rapid thermal cycling environments.

2、 Medium temperature range (700~1400 ℃)

High alumina brick and silica brick

Wear resistance fluctuation: The wear resistance of high alumina bricks decreases at 700-900 ℃ (influenced by the peak elastic modulus), but silicon carbide bricks (containing silicon carbide) maintain excellent wear resistance due to the stability of SiC.

Liquid phase formation: Clay bricks have better wear resistance than room temperature at 1200-1350 ℃ due to the moderate viscosity of the liquid phase, which lubricates the friction between particles; But after exceeding 1400 ℃, the viscosity of the liquid phase drops sharply, and the wear resistance decreases sharply.

Alkaline bricks (magnesia chrome bricks, chrome corundum bricks)

Reverse trend enhancement: Chromium containing bricks (such as chromium corundum bricks) actually improve their wear resistance with decreasing temperature, as Cr ₂ O3 forms a stable crystal structure at low temperatures.

3、 High temperature range (1400~1800 ℃)

Jadeite quality and silicon carbide brick

Corundum brick (Al ₂ O ∝ ≥ 90%): has good volume stability at high temperatures, and its wear resistance depends on density. However, when it exceeds 1600 ℃, the liquid phase at the grain boundary may weaken its wear resistance.

Silicon carbide brick: The wear resistance remains almost unchanged below 1800 ℃, but it is necessary to avoid an oxidizing atmosphere (SiC oxidation to generate SiO ₂ will reduce strength).

Zirconium containing bricks (such as zirconia alumina bricks)

Corrosion resistance dominant: In glass kilns (1600 ℃), the high temperature stability of ZrO ₂ makes its wear resistance superior to other materials, but the cost is higher.

4、 Ultra high temperature (>1800 ℃)

Special materials (such as silicon nitride combined with silicon carbide)

Suitable for extreme working conditions: Silicon nitride (Si ∝ N ₄) forms a protective layer at ultra-high temperatures, with better wear resistance than pure silicon carbide, and is used in aerospace or nuclear industries.

Electric fused alumina brick: White alumina brick (bulk density ≥ 3.0 g/cm ³) maintains high hardness and low porosity above 1800 ℃.

5、 Summary of Key Influencing Factors

factor

Low temperature (＜ 700 ℃)

Medium temperature (700~1400 ℃)

High temperature (>1400 ℃)

Material Hardness

Silicon carbide>Corundum>High alumina

Silicon carbide>Corundum>Silicon Mo

Silicon carbide>Zirconia corundum>Corundum

Liquid phase influence

none

Liquid phase enhanced wear resistance of clay bricks

Liquid phase reduction of wear resistance in high alumina bricks

chemical stability

All materials are stable

Chromium containing brick alkali resistant slag

Zirconia corundum is resistant to glass liquid erosion

Typical Applications

Boiler lining, CFB furnace

Transition zone of cement kiln, metallurgical furnace

Glass melting furnace, ultra-high temperature reactor

6、 Selection suggestions

Transition zone of cement kiln: Priority should be given to using silica bricks (Al ₂ O3+SiC) to balance medium temperature wear resistance and high temperature stability.

Metallurgical furnace outlet: Corundum silicon carbide composite brick, resistant to iron erosion and high-temperature corrosion.

Low temperature wear-resistant environment: high alumina bricks (low cost) or steel fiber reinforced castables (resistant to mechanical impact).

Future trends include the development of nano modified bricks (such as plate-like corundum) and environmentally friendly chromium free materials (such as dolomite bricks) to cope with more stringent working conditions.