Silicon Nitride Bonded Silicon Carbide Brick

Silicon nitride-bonded silicon carbide brick is a high-performance refractory material, primarily manufactured by mixing powdered silicon (Si) and silicon carbide (SiC) and then heating the mixture in a nitrogen atmosphere. It is a high-hardness non-metallic material with excellent wear resistance, high-temperature strength, strong resistance to high-temperature creep and slag corrosion, good thermal shock stability, and good oxidation resistance.

一.Physical And Chemical Indicators of Silicon nitride-bonded silicon carbide brick

二. Characteristics of Silicon Nitride-Bonded Silicon Carbide Bricks

Application Suitability: These three categories are used in high-end applications, doubling the lifespan.

Strong High-Temperature Oxidation Resistance: Ordinary silicon carbide bricks are prone to oxidation and loosening above 1200℃, while the Si₃N₄ in these bricks forms a dense SiO₂-Al₂O₃ protective layer during high-temperature oxidation. The oxidation rate at 1400℃ is only 1/10 of that of ordinary silicon carbide bricks;

Superior Wear Resistance: Si₃N₄ (Mohs hardness 9.5) and SiC work together, resulting in twice the wear resistance of ordinary silicon carbide bricks at room temperature, suitable for applications with high material abrasion;

Excellent Thermal Shock Resistance: The thermal expansion coefficient at 1000℃ is only 4×10⁻⁶/℃ (70% of that of ordinary silicon carbide bricks), and it withstands over 40 cycles of water quenching at 1100℃ without cracking, suitable for high-end equipment with frequent start-ups and shutdowns.

三.Application of Silicon Nitride-Bonded Silicon Carbide Bricks

Waste Incinerator Furnace Chamber: The furnace chamber experiences high temperatures (1000-1200℃), fly ash erosion, and an oxidizing atmosphere simultaneously. The oxidation resistance and wear resistance of high-nitrogen silicon nitride bonded silicon carbide bricks prevent rapid brick damage. After use by an environmental protection company, the furnace chamber lifespan was extended from 8 months to 24 months, reducing the risk of interruptions in waste treatment.

Blast Furnaces and Non-ferrous Metal Smelting:

Silicon nitride bonded silicon carbide refractory materials are widely used in the steel metallurgy industry. Due to their excellent thermal shock stability, slag resistance, and oxidation resistance, these materials are commonly used in the lower parts of blast furnace bodies, such as the furnace hearth, with good results. Silicon nitride bonded silicon carbide products have good resistance to alkali metal vapor corrosion. In iron and steelmaking systems, their non-wetting properties towards molten steel and iron, and low wettability to slag, improve their corrosion resistance and slag penetration resistance. In the non-ferrous metal smelting industry, the non-wetting properties of silicon nitride bonded silicon carbide products towards molten aluminum, copper, and magnesium have led to their gradual application in this industry.