Silicon nitride brick is a refractory material product mainly composed of Si ∝ N ₄, with high refractoriness, high-temperature flexural strength of 200~700MPa, and oxidation temperature resistance up to 1400 ℃. It has a density of 3.19g/cm ³, a thermal expansion coefficient of 2.53 × 10 ⁻⁶/℃, a thermal conductivity of 18.4W/(m · K) at 1200 ℃, outstanding resistance to alkaline slag erosion, and certain adaptability to acidic slag. Its thermal shock stability can pass thousands of heat exchange tests at 1200-2000 ℃.
Performance
Silicon nitride brick is a special refractory material product mainly composed of Si3N4. Density 3.19g/cm3. The coefficient of expansion is small, at 2.53 × 10-6/℃. Thermal conductivity at 1200 ℃ is 18.4W/(m · K). Good thermal stability, with thousands of heat exchanges at 1200-2000 ℃ without damage. The flexural strength can reach 200~700MPa, the oxidation temperature resistance is 1400 ℃, and it can reach 1870 ℃ in a reducing atmosphere. Room temperature resistivity 1.1 × 1014 Ω· m. Prepared by silicon powder nitriding and sintering or hot pressing method.
Production method
Silicon nitride bricks are produced by sintering or hot pressing silicon powder after nitriding. The production process of firing silicon nitride bricks is generally similar to that of magnesium bricks. In order to eliminate the influence of MgO, Cr2O3, Al2O3, or direct bonding with silicon nitride bricks during the firing process of bricks.
Advantages
Silicon nitride bricks have high refractoriness, high temperature strength, strong resistance to alkaline slag erosion, excellent thermal stability, and also have certain adaptability to acidic slag.
Application
Used for manufacturing high-temperature bearings, metallurgical crucibles, semiconductor area melting boats, etc. in industries such as aviation, metallurgy, machinery, and semiconductors.
