The sialon-bonded aluminum carbon bricks are produced by incorporating silicon nitride and ultra-fine alumina powders, followed by firing in a nitrogen-rich atmosphere. This process results in the formation of a sialon phase, which is rich in nitrogen, significantly enhancing the material’s thermal and chemical stability. The use of silicon nitride as an intermediate to create sialon-bonded refractories proves effective, especially when certain industrial conditions are not available. Sialon can be synthesized from aluminosilicate materials like kaolin, where nitrogen, along with carbon or aluminum powder, replaces part of the oxygen, making the production more cost-effective. While the use of aluminum powder is relatively low-cost, controlling the final brick size remains a challenge.
In contrast, silicon nitride-bonded silicon carbide bricks represent a special case of sialon-based materials. These are created by mixing high-purity silicon powder with silicon carbide in specific proportions and then undergoing nitriding and sintering under high pressure and vacuum conditions (with 99.99% pure nitrogen at temperatures between 1300°C and 1352°C). When alumina powder is added, it helps form a more stable bonding phase, but this often leads to difficulties in controlling the product’s dimensions and density. Additionally, using aluminum powder or silicon nitride for cerium bonding tends to be too costly, limiting its practical application.
Most users in the steel industry prefer large-sized bricks for blast furnaces. However, manufacturing such large components in high-temperature and high-pressure nitriding environments is expensive and economically impractical. Many older refractory plants lack the necessary nitriding furnaces, so alternative methods—such as adding chemical additives or burning carbon—may offer viable solutions.
Some studies have explored the use of sialon in producing sialon-bonded corundum products, incorporating 5% Y₂O₃ as a sintering aid to create a network of sialon that cross-links the dispersed corundum particles, resulting in a dense structure. This method relies on liquid-phase sintering. Although laboratory performance meets expectations, the industrial environment poses significant challenges, including exposure to acidic or alkaline slags, or alkali vapor corrosion. Y₂O₃ tends to form low-melting glass phases with aluminosilicates, which can degrade the material’s performance at high temperatures.
From a microstructural perspective, the bonding in sialon-bonded silicon carbide and corundum bricks typically consists of an amorphous sialon phase. If the process design is optimized, the nitrogen content in the sialon phase is high; otherwise, it may be very low. The self-made sialon-bonded aluminum carbon bricks, made by adding silicon nitride and undergoing nitriding and firing, produce a strong sialon bonding phase. A clear nitrogen peak is observed, and the substrate can generate sialon in situ, further improving the material's properties.
Valve Diaphragm
Diaphragm is also called membrane, which is a very important sealing component of the valve. NINGBO DOTEC manufactures various diaphragms for pulse valves and solenoid valves. We use all high quality raw materials to ensure long service life.
Valve Diaphragm Types:
1. GOYEN Type Pulse Valve Diaphragm
2. ASCO Type Pulse Valve Diaphragm
3. SBFEC Type Pulse Valve Diaphragm
4. TURBO Type Pulse Valve Diaphragm
5. MECAIR Type Pulse Valve Dipahragm
6. JOIL Type Pulse Valve Diaphragm
7. Norgren Buschjost Type Pulse Valve Diaphragm
8. AUTEL Type Pulse Valve Diaphragm
9. TAEHA Type Pulse Valve Diaphragm
10. Other Pulse Valve Diaphragm
11. Water Solenoid Valve Diaphragm
Pulse Valve Diaphragm, Solenoid Valve Diaphragm, Pulse Valve Membrane, Pulse Jet Valve Diaphragm
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