Products

Silicon Carbide Refractory Bricks I. Product Types and Classification Standards Oxide-Bonded Type (SC-O): SiC content 70–80%, silicate-bonded phase 15–20%; bulk density 2.5–2.7 g/cm³; service temperature ≤1350°C Nitride-Bonded Type (SC-N): Si₃N₄/Si₂N₂O bonding phase 20–30%; SiC content ≥85%; high-temperature strength (at 1400°C) ≥30 MPa Self-Bonded Type (SC-RB): Recrystallized silicon carbide (SiC ≥99%); apparent porosity ≤15%; thermal conductivity 120 W/(m·K). New Composite Products: Gradient Structure—working face SiC 95% → transition layer 80% → matrix layer 65%; nano-SiC coating (wear resistance improved by 50%). II. Advanced Production Processes Raw Material Processing System: SiC particle size grading (3–1 mm : 1–0.1 mm : <0.1 mm = 4:3:3); surface modification of silicon nitride powder (D50 = 0.8 μm); intelligent forming processes, including isostatic pressing (pressure 200–250 MPa) and 3D printing for precision shaping of complex components; special sintering technologies such as atmosphere-protected sintering (N₂, 1800–2200°C) and spark plasma sintering (SPS), which reduces the sintering cycle by 80%; post-processing techniques including chemical vapor deposition (CVD) for surface densification and laser precision machining with tolerances of ±0.1 mm. III. Core Application Areas in 2026 Industry Applications Typical Components Performance New Energy Lithium-Ion Battery Sintering Furnaces: Roller rods’ service life extended to 5 years Electronic Materials Silicon Carbide Single-Crystal Growth Furnaces: Crucibles—thermal field uniformity improved by 30% Environmental Protection Hazardous Waste Incinerators: Lining—corrosion resistance enhanced by 60% Aerospace Rocket Engine Nozzles: Temperature resistance up to 2000°C IV. Comparative Performance Advantages vs. Traditional Materials Thermal Conductivity: 120 W/(m·K) (high-alumina bricks only 2.1); Wear Resistance: Volumetric wear ≤0.5 cm³ (ASTM C704); Thermal Shock Resistance: 50 cycles (water quenching at 1100°C); Economic Indicators Initial Cost: 40% lower than zirconia-corundum bricks; Maintenance Interval: 8–10 years (traditional materials 3–5 years). V. Physicochemical Specifications (GB/T 2026–SC) 1. Basic Properties (SC-N Type): — Bulk Density: 2.7–2.9 g/cm³ — Apparent Porosity: 12–15% — Cold Crushing Strength: ≥150 MPa High-Temperature Characteristics: — Load Softening Point (0.2 MPa): ≥1650°C — Flexural Strength (at 1400°C): ≥35 MPa Special Properties: — Resistance to Molten Aluminum Erosion: ≤1.2 mm/100 h (at 900°C) — Coefficient of Thermal Expansion: 4.5 × 10⁻⁶/°C (20–1000°C)

Sintered Heavy-Duty Mullite Refractory Bricks I. Main Product Types Standard Type (ML-70): Composition: Al₂O₃ 68–72%, SiO₂ 25–28%; Bulk Density: 2.6–2.8 g/cm³; Apparent Porosity: ≤18%; High-Purity Type (ML-80): Al₂O₃ ≥78% (using industrial-grade alumina); Load Softening Temperature: ≥1700°C; High-Temperature Flexural Strength (at 1400°C): ≥12 MPa; Composite Reinforced Type (New Technology 2025): Addition of 5–8% nano-ZrO₂, improving thermal shock resistance to 35 cycles (water quenching at 1100°C) and reducing thermal conductivity by 20%. II. Intelligent Production Process Raw Material Preprocessing: AI-based sorting of high-alumina bauxite (Al₂O₃ ±0.5%); Pre-synthesis of mullite (1600°C for 4 hours); Digital Forming System: Isostatic Pressing (200–250 MPa); Online X-ray Flaw Detection (100% defect detection rate); Hydrogen-Fired Sintering Technology: Full-Oxygen Combustion Tunnel Kiln (1750°C ±5°C), reducing carbon footprint by 30% compared with conventional kilns. III. Typical Applications in 2026 Application Fields and Service Locations: Performance Highlights Ceramic Industry: Roller Kiln Supporting Structure—Service Life Extended to 5 Years; Chemical Industry: Ethylene Glycol Reactor Lining—Corrosion Resistance Improved by 40%; New Energy: Lithium-Battery Material Sintering Kiln—Energy Consumption Reduced by 18%; Aerospace: Rocket Exhaust Deflector—Temperature Resistance Up to 1850°C. IV. Performance Advantages Compared with Traditional High-Alumina Bricks Thermal Shock Resistance: 25 cycles vs. 8 cycles (water quenching at 1100°C); High-Temperature Creep: 0.3% vs. 1.2% (1600°C for 50 hours); Economic Analysis: Initial Cost—50% Lower than Electrofused Mullite Bricks; Maintenance Interval—3 Years Without Major Overhaul (vs. 2 Years for Conventional Bricks). V. Physicochemical Specifications (GB/T 2026–ML) 1. Basic Properties (ML-70): – Refractoriness: ≥1790°C – Room-Temperature Compressive Strength: ≥80 MPa High-Temperature Characteristics: – Load Softening Point: ≥1650°C – Coefficient of Thermal Expansion: 5.5×10⁻⁶/°C (20–1000°C) Special Indicators: – Alkali Corrosion Resistance (K₂O): Weight Gain ≤0.8% (1400°C for 100 hours) – Microwave Loss: tanδ ≤0.001 (2.45 GHz)

Sintered Heavy-Duty Mullite Refractory Bricks I. Main Product Types Standard Type (ML-70): Composition: Al₂O₃ 68–72%, SiO₂ 25–28%; Bulk Density: 2.6–2.8 g/cm³; Apparent Porosity: ≤18%; High-Purity Type (ML-80): Al₂O₃ ≥78% (using industrial-grade alumina raw material); Load Softening Temperature: ≥1700°C; High-Temperature Flexural Strength (at 1400°C): ≥12 MPa; Composite Reinforced Type (New Technology 2025): Addition of 5–8% nano-ZrO₂, improving thermal shock resistance to 35 cycles (water quenching at 1100°C) and reducing thermal conductivity by 20%. II. Intelligent Production Process Raw Material Preprocessing: AI-based sorting of high-alumina bauxite (Al₂O₃ ±0.5%); Pre-synthesis of mullite (1600°C for 4 hours); Digital Forming System: Isostatic Pressing (200–250 MPa); Online X-ray Nondestructive Testing (100% defect detection rate); Hydrogen-Fired Sintering Technology: Full-Oxygen Combustion Tunnel Kiln (1750°C ±5°C), reducing carbon footprint by 30% compared with conventional kilns. III. Typical Applications in 2026 Application Fields | Component | Performance Highlights Ceramic Industry | Roller Hearth Kiln | Load-Bearing Structure | Service Life Extended to 5 Years Chemical Industry | Ethylene Glycol Reactor Lining | Corrosion Resistance Improved by 40% New Energy | Lithium-Ion Battery Material Sintering Kiln | Energy Consumption Reduced by 18% Aerospace | Rocket Exhaust Deflector | Temperature Resistance Up to 1850°C IV. Performance Advantages Compared with Traditional High-Alumina Bricks Thermal Shock Resistance: 25 cycles vs. 8 cycles (water quenching at 1100°C); High-Temperature Creep: 0.3% vs. 1.2% (1600°C for 50 hours); Economic Analysis: Initial Cost: 50% lower than electrofused mullite bricks; Maintenance Interval: 3 years without major overhauls (vs. 2 years for traditional bricks). V. Physicochemical Specifications (GB/T 2026–ML) 1. Basic Properties (ML-70): – Refractoriness: ≥1790°C – Cold Crushing Strength: ≥80 MPa High-Temperature Characteristics: – Load Softening Point: ≥1650°C – Coefficient of Thermal Expansion: 5.5×10⁻⁶/°C (20–1000°C) Special Indicators: – Alkali Resistance (K₂O): Weight Gain ≤0.8% (1400°C for 100 hours) – Microwave Loss: tanδ ≤0.001 (2.45 GHz)

Sintered Heavy-Duty Mullite Refractory Bricks I. Main Product Types Standard Type (ML-70): Composition: Al₂O₃ 68–72%, SiO₂ 25–28%; Bulk Density: 2.6–2.8 g/cm³; Apparent Porosity: ≤18%; High-Purity Type (ML-80): Al₂O₃ ≥78% (using industrial-grade alumina); Load Softening Temperature: ≥1700°C; High-Temperature Flexural Strength (at 1400°C): ≥12 MPa. Composite Reinforced Type (New Technology 2025): Incorporation of 5–8% nano-ZrO₂, enhancing thermal shock resistance to 35 cycles (water quenching at 1100°C) and reducing thermal conductivity by 20%. II. Intelligent Production Process Raw Material Preprocessing: AI-based sorting of high-alumina bauxite (Al₂O₃ ±0.5%); Pre-synthesis of mullite (1600°C for 4 hours); Digital Forming System: Isostatic pressing at 200–250 MPa; Online X-ray Nondestructive Testing (100% defect detection rate); Hydrogen-fueled firing technology using full-oxygen combustion in a tunnel kiln (1750°C ±5°C), reducing the carbon footprint by 30% compared with conventional kilns. III. Typical Applications in 2026 Application Fields and Service Locations: Performance Highlights— Ceramic Industry: Roller Kiln load-bearing structure lifespan extended to 5 years; Chemical Industry: Ethylene glycol reactor lining exhibits 40% improved erosion resistance; New Energy: Lithium-ion battery material sintering kiln energy consumption reduced by 18%; Aerospace: Rocket exhaust nozzle shroud withstands temperatures up to 1850°C. IV. Performance Advantages Compared with Conventional High-Alumina Bricks Thermal Shock Resistance: 25 cycles vs. 8 cycles (water quenching at 1100°C); High-Temperature Creep: 0.3% vs. 1.2% (at 1600°C for 50 hours); Economic Analysis: Initial Cost: 50% lower than electrofused mullite bricks; Maintenance Interval: 3 years without major overhauls (compared with 2 years for conventional bricks). V. Physicochemical Specifications (GB/T 2026–ML) 1. Basic Properties (ML-70): – Refractoriness: ≥1790°C – Room-Temperature Compressive Strength: ≥80 MPa High-Temperature Characteristics: – Load Softening Point: ≥1650°C – Coefficient of Thermal Expansion: 5.5×10⁻⁶/°C (20–1000°C) Special Indicators: – Alkali-Erosion Resistance (K₂O): Weight Gain ≤0.8% (at 1400°C for 100 hours) – Microwave Loss: tanδ ≤0.001 (at 2.45 GHz)

Sillimanite Refractory Bricks I. Core Product Types GXS-50 Series (Basic Type): Composition: Al₂O₃ ≥ 50%, SiO₂ ≤ 45%; Apparent Porosity: ≤ 18%; Load Softening Point: ≥ 1550°C. GXS-60 Series (High-Performance Type): Al₂O₃ ≥ 60%, Fe₂O₃ ≤ 1.0%; Thermal Shock Resistance: ≥ 20 cycles (water quenching at 100°C); Bulk Density: ≥ 2.5 g/cm³. New Composite Brick: Sillimanite + Silicon Nitride Combination (Si₃N₄ 8–12%): Alkali Resistance Improved by 60%; Abrasion Resistance Increased by a Factor of Three. II. Intelligent Manufacturing Processes Raw Material Purification System: Sillimanite Concentrate Flotation (Al₂O₃ ≥ 58%); Particle Size Control: Optimized Grading Model—coarse (1–3 mm): medium (0.1–1 mm): fine (<0.1 mm) = 4:3:3. Low-Temperature Intensification Process: Andalusite Composite Addition (sintering temperature reduced to 1350°C). Microwave-Assisted Drying (energy consumption reduced by 40%). Digital Firing System: Hydrogen-Fired Tunnel Kiln (1400°C ± 5°C) with Real-Time Thermal Imaging Monitoring (product yield ≥ 98%). III. Applications Typical Application Scenarios and Technical Benefits Glass Industry: Flow-Through Mold Lifespan Extended to 5 Years; Iron and Steel Metallurgy: Blast Furnace Hearth Resistant to CO Erosion, with Erosion Resistance Improved by 70%; Ceramic Manufacturing: Kiln Furniture (Briquettes/Plungers) with Thermal Cycling Life Up to 200 Cycles; New Energy: Polycrystalline Silicon Ingot Casting Molds with Silicone Adhesion Reduced by 80%. IV. Performance Advantage Analysis Compared with Traditional Materials High-Temperature Resistance: 1650°C vs. High-Alumina Brick 1500°C; Thermal Shock Resistance: 20 cycles vs. Clay Brick 5 cycles; Erosion Resistance: Glass Molten Erosion Rate 0.3 mm/year; Economic Performance: Cost 60% Lower than Electrofused Zirconia-Corundum Brick; Maintenance Interval: 3 Years Without Replacement. V. Latest Physicochemical Specifications 1. Basic Properties (GXS-60): Bulk Density: 2.55 ± 0.05 g/cm³ (GB/T 2998–2025); Compressive Strength: ≥ 60 MPa (ISO 10059:2026); High-Temperature Characteristics: Linear Change After Reheating: ±0.1% (1500°C × 2 h); Thermal Conductivity: 1.5 W/(m·K) (800°C); Special Indicators: Resistance to Glass Erosion: ≤ 0.5 mm/1000 h (1450°C); Resistance to Alkalinity: Weight Gain Due to K₂O Erosion ≤ 0.3%.

Sillimanite Refractory Bricks I. Core Product Types GXS-50 Series (Basic Type): Composition: Al₂O₃ ≥ 50%, SiO₂ ≤ 45%; Apparent Porosity: ≤ 18%; Load Softening Point: ≥ 1550°C. GXS-60 Series (High-Performance Type): Al₂O₃ ≥ 60%, Fe₂O₃ ≤ 1.0%; Thermal Shock Resistance: ≥ 20 cycles (water quenching at 100°C); Bulk Density: ≥ 2.5 g/cm³. New Composite Brick: Sillimanite + Silicon Nitride Combination (Si₃N₄ 8–12%): Alkali Resistance Improved by 60%; Abrasion Resistance Increased by a Factor of Three. II. Intelligent Manufacturing Processes Raw Material Purification System: Sillimanite Concentrate Flotation (Al₂O₃ ≥ 58%); Particle Size Control: Optimized Grading Model—coarse (1–3 mm): medium (0.1–1 mm): fine (<0.1 mm) = 4:3:3. Low-Temperature Intensified Process: Andalusite Composite Addition (sintering temperature reduced to 1350°C). Microwave-Assisted Drying (energy consumption reduced by 40%). Digital Firing System: Hydrogen-Fired Tunnel Kiln (1400°C ± 5°C) with Real-Time Thermal Imaging Monitoring (product yield ≥ 98%). III. Applications Typical Application Scenarios and Technical Benefits Glass Industry: Flow-Through Mold Lifespan Extended to 5 Years; Iron and Steel Metallurgy: Blast Furnace Hearth Exhibits 70% Improved Resistance to CO Erosion; Ceramic Manufacturing: Kiln Furniture (Briquettes/Punches) Endures 200 Thermal Cycles; New Energy: Polycrystalline Silicon Ingot Casting Molds Show 80% Reduction in Silicon Adhesion. IV. Performance Advantage Analysis Compared with Traditional Materials High-Temperature Resistance: 1650°C vs. High-Alumina Brick 1500°C; Thermal Shock Resistance: 20 cycles vs. Clay Brick 5 cycles; Erosion Resistance: Glass Molten Erosion Rate of 0.3 mm/year; Economic Performance: Cost 60% Lower than Electrofused Zirconia-Corundum Brick; Maintenance Interval: 3 Years Without Replacement. V. Latest Physicochemical Specifications 1. Basic Properties (GXS-60): Bulk Density: 2.55 ± 0.05 g/cm³ (GB/T 2998–2025); Compressive Strength: ≥ 60 MPa (ISO 10059:2026); High-Temperature Characteristics: Linear Change After Reheating: ±0.1% (1500°C × 2 h); Thermal Conductivity: 1.5 W/(m·K) (800°C); Special Indicators: Resistance to Glass Erosion: ≤ 0.5 mm/1000 h (1450°C); Resistance to Alkalinity: Weight Gain Due to K₂O Erosion ≤ 0.3%.

Zirconia–Silica Refractory Bricks I. Main Product Types Standard Zirconia–Silica Brick (ZS-65): Composition: ZrO₂ 65±2%, SiO₂ 32±2%. Characteristics: Bulk density 3.5–3.8 g/cm³; apparent porosity ≤18%. Applications: Upper structures of glass furnaces. Zirconia-Enhanced Type (ZSM-75): Contains 8–12% monoclinic ZrO₂, increasing thermal shock resistance to 25 cycles under 1100°C water quenching. Suitable for tundish permeable bricks. Composite Zirconia–Mullite Gradient Structure (ZrO₂ gradient from 40% to 15%): Thermal conductivity reduced by 30%. II. Intelligent Production Process Raw Material Processing: Microwave calcination of zircon sand at 1500°C for 2 hours. Particle size control: #3–1 mm: 1–0.1 mm; <0.1 mm. Low-Temperature Bonding Technology: Aluminum phosphate binder (firing temperature reduced to 1450°C), reducing CO₂ emissions by 40%. Digital Firing System: Hydrogen-fired shuttle kiln operating at 1600°C ±5°C, with an intelligent temperature-control module providing independent regulation in 30 zones. III. Application Scenarios and Typical Cases—Performance Data Electronic glass high-borosilicate melting furnace arch: Service life extended to 7 years. New-energy photovoltaic glass tin bath: Energy consumption reduced by 22%. Aerospace rocket nozzle insulation layer: Temperature resistance up to 2000°C. Environmental hazardous-waste incinerator lining: Corrosion resistance improved by 50%. IV. Performance Advantages Compared with Traditional Materials Resistance to glass erosion: 0.5 mm/year (compared with 1.2 mm for AZS bricks). Thermal-shock stability: 20 cycles (versus only 5 for silica bricks). Economic Analysis: Cost 35–40% lower than AZS bricks; maintenance interval of 5 years, eliminating major overhauls. V. Latest Physicochemical Specifications 1. Basic Properties (ZS-65): – Bulk density: 3.65±0.15 g/cm³ (GB/T 2997-2025); – Compressive strength: ≥80 MPa (ISO 10059-2:2026). 2. High-Temperature Characteristics: – Load-softening point: ≥1680°C (at 0.2 MPa); – Coefficient of thermal expansion: 0.45% (at 1000°C). 3. Special Indicators: – Resistance to sodium–calcium glass erosion: ≤0.8 mm/24 h (at 1500°C); – Radioactivity: Internal radiation index ≤0.3.

Zirconia–Silica Refractory Bricks I. Main Product Types Standard Zirconia–Silica Brick (ZS-65): Composition: ZrO₂ 65±2%, SiO₂ 32±2%. Characteristics: Bulk density 3.5–3.8 g/cm³; apparent porosity ≤18%. Applications: Upper structures of glass furnaces. Zirconia-Reinforced Type (ZSM-75): Contains 8–12% monoclinic ZrO₂, increasing thermal shock resistance to 25 cycles under 1100°C water quenching. Suitable for: Tundish permeable bricks. Composite Zirconia–Mullite Gradient Structure (ZrO₂ gradient from 40% to 15%): Thermal conductivity reduced by 30%. II. Intelligent Production Process Raw Material Processing: Microwave Calcination of Zircon Sand (1500°C for 2 hours). Particle Size Control: #3–1 mm: 1–0.1 mm; <0.1 mm. Low-Temperature Bonding Technology: Aluminum Phosphate Binder (firing temperature reduced to 1450°C), reducing CO₂ emissions by 40%. Digital Firing System: Hydrogen-Fired Shuttle Kiln (1600°C ±5°C) with Intelligent Temperature-Control Modules (30 independent zones). III. Application Scenarios Typical Case Studies and Performance Data Electronic Glass High-Borosilicate Melting Furnace: Service Life of the Vault Extended to 7 Years. New Energy Photovoltaic Glass Tin Bath: Energy Consumption Reduced by 22%. Aerospace Rocket Nozzle Heat Shield: Temperature Resistance Up to 2000°C. Environmental Hazardous Waste Incinerator Lining: Corrosion Resistance Improved by 50%. IV. Performance Advantages Compared with Traditional Materials Resistance to Glass Erosion: 0.5 mm/year (AZS brick: 1.2 mm); Thermal Shock Stability: 20 cycles (silica brick: only 5 cycles). Economic Analysis: Cost 35–40% lower than AZS brick; Maintenance Interval: 5 years without major overhauls. V. Latest Physicochemical Indices 1. Basic Properties (ZS-65): – Bulk Density: 3.65±0.15 g/cm³ (GB/T 2997-2025); – Compressive Strength: ≥80 MPa (ISO 10059-2:2026). 2. High-Temperature Characteristics: – Load Softening Point: ≥1680°C (0.2 MPa); – Coefficient of Thermal Expansion: 0.45% at 1000°C. 3. Special Indicators: – Resistance to Soda-Lime Glass Erosion: ≤0.8 mm/24 h at 1500°C; – Radioactivity: Internal Radiation Index ≤0.3.

Main Types of Low-Thermal-Conductivity Mullite Composite Refractory Bricks Low‑thermal‑conductivity mullite composite refractory bricks are classified into three categories based on their structure: homogeneous low‑thermal‑conductivity bricks; multilayer composite bricks; and zirconia–mullite bricks. The core of the production process focuses on reducing the thermal conductivity coefficient: Raw Material Processing: Low‑impurity aggregates such as tabular corundum and electrofused mullite are selected, with Fe₂O₃ content controlled at ≤0.6%. Structural Compositing: Multilayer bricks employ a gradient batching approach (with the working layer containing ≥70% Al₂O₃ and the insulation layer containing ≤65%), followed by isostatic pressing and sintering at 1700°C.

Main Types of Silicon Nitride Refractory Bricks Silicon nitride refractory bricks are primarily categorized into three types based on differences in production processes and performance: Reaction‑Bonded Silicon Nitride (RBSN), Hot‑Pressed Silicon Nitride (HPSN), and Sintered Silicon Nitride (SSN). RBSN is produced by directly nitriding silicon powder, resulting in a relatively low density (approximately 2.5 g/cm³); HPSN and SSN, on the other hand, boast higher densities (up to 3.2 g/cm³) and superior physical properties. In addition, there are composite products such as Sialon‑bonded silicon carbide bricks and β‑SiC‑bonded silicon carbide bricks, which optimize performance by adjusting the bonding phase—such as Si₃N₄, Si₂ON₂, and others. Production Process The core process for manufacturing silicon nitride refractory bricks is the nitridation reaction of silicon powder. Taking silicon nitride‑bonded silicon carbide bricks as an example, silicon carbide particles are mixed with silicon powder and then formed into shape before being sintered in a nitrogen atmosphere at 1300–1400°C. During this process, silicon reacts with nitrogen to form the Si₃N₄ bonding phase (reaction equation: 3Si + 2N₂ → Si₃N₄). Key process controls include silicon powder particle size (fine silicon powder is used for low‑temperature zones, while coarse silicon powder is employed in high‑temperature areas), nitrogen purity (≥99.999%), and stepwise temperature ramping—such as staged holding at 1150°C, 1250°C, and 1400°C. For composite products (such as Sialon‑bonded bricks), additives like Al₂O₃ are incorporated to form solid solution phases. Application Scenarios Silicon nitride refractory bricks are widely used in extreme high‑temperature and corrosive environments: Metallurgy: As lining for the belly of blast furnaces and side linings of aluminum electrolytic cells, offering resistance to molten iron erosion and cryolite melt corrosion; Ceramic and Glass Industries: As kiln furniture and hearth plates, providing excellent resistance to high‑temperature deformation; Chemical Industry: As linings for oil and gas cracking furnaces; Energy and Environmental Protection: As linings for waste incineration furnaces and components for nuclear reactors, leveraging their radiation resistance; Aerospace: As nozzle vanes for rocket engines, capable of withstanding the impact of high‑temperature combustion gases. Performance Advantages The advantages of silicon nitride refractory bricks are evident in the following areas: 1) High‑Temperature Stability: With a melting point of 1900°C, silicon nitride remains stable even at temperatures ranging from 1450–1550°C; 2) Mechanical Properties: Featuring flexural strengths of 400–800 MPa, hot‑pressed silicon nitride exhibits hardness approaching that of diamond; 3) Thermal Shock Resistance: With a low coefficient of thermal expansion (3 × 10⁻⁶/°C), silicon nitride minimizes thermal stress and crack formation; 4) Chemical Inertness: Resistant to attack by acids, alkalis, and molten metals—including exhibiting a large wetting angle with molten aluminum; 5) Wear Resistance: Thanks to its high hardness (Mohs scale 9), silicon nitride is ideally suited for areas subject to abrasive wear. Compared to traditional high‑alumina bricks, silicon nitride offers more than a 40% increase in high‑temperature strength. Physicochemical Specifications Typical physicochemical specifications for silicon nitride‑bonded silicon carbide bricks include: Chemical Composition: SiC ≥ 50%, Si₃N₄ bonding phase 20–40%, impurities (Fe₂O₃ + TiO₂) < 1.5%; Physical Properties: Bulk density 2.5–3.2 g/cm³, apparent porosity 12–18%; High‑Temperature Performance: Refractoriness ≥ 1790°C, load softening temperature ≥ 1650°C, thermal shock stability (water quenching from 1100°C) ≥ 25 cycles; Electrical Properties: Room‑temperature resistivity 10¹⁵–10¹⁶ Ω·cm, dielectric constant 9.4–9.5. Special‑purpose products, such as Sialon‑bonded bricks, must also meet specific Al₂O₃ content requirements (5–15%).

Main Types of Silicon Nitride Refractory Bricks Silicon nitride refractory bricks are primarily categorized into three types based on differences in production processes and performance: Reaction‑Bonded Silicon Nitride (RBSN), Hot‑Pressed Silicon Nitride (HPSN), and Sintered Silicon Nitride (SSN). RBSN is produced by directly nitriding silicon powder, resulting in a relatively low density—approximately 2.5 g/cm³—while HPSN and SSN boast higher densities, reaching up to 3.2 g/cm³, and exhibit superior physical properties. In addition, there are composite products such as Sialon‑bonded silicon carbide bricks and β‑SiC‑bonded silicon carbide bricks, which optimize performance by adjusting the bonding phase—such as Si₃N₄, Si₂ON₂, and others. Production Process The core process for manufacturing silicon nitride refractory bricks is the nitridation reaction of silicon powder. Taking silicon nitride‑bonded silicon carbide bricks as an example, silicon carbide particles are mixed with silicon powder and then formed into shape before being sintered in a nitrogen atmosphere at 1300–1400°C. During this process, silicon reacts with nitrogen to form the Si₃N₄ bonding phase (reaction equation: 3Si + 2N₂ → Si₃N₄). Key process controls include silicon powder particle size—fine silicon powder is used for low‑temperature zones, while coarse silicon powder is employed in high‑temperature areas—as well as nitrogen purity (≥99.999%) and staged heating profiles, such as holding temperatures at 1150°C, 1250°C, and 1400°C. For composite products—such as those bonded with Sialon—additives like Al₂O₃ must be incorporated to form solid solution phases. Application Scenarios Silicon nitride refractory bricks are widely used in extreme high‑temperature and corrosive environments: Metallurgy: As lining for the belly of blast furnaces and side linings of aluminum electrolysis cells, offering resistance to molten iron erosion and cryolite melt corrosion; Ceramic and Glass Industries: As kiln furniture and hearth plates, providing excellent resistance to high‑temperature deformation; Chemical Industry: As linings for oil and gas cracking furnaces; Energy and Environmental Protection: As linings for waste incineration furnaces and components for nuclear reactors, leveraging their radiation resistance; Aerospace: As nozzle vanes for rocket engines, capable of withstanding the impact of high‑temperature combustion gases. Performance Advantages The advantages of silicon nitride refractory bricks are evident in the following areas: 1) High‑Temperature Stability: With a melting point of 1900°C, these bricks remain stable even at temperatures ranging from 1450–1550°C; 2) Mechanical Properties: Featuring flexural strengths of 400–800 MPa, hot‑pressed silicon nitride exhibits hardness approaching that of diamond; 3) Thermal Shock Resistance: With a low coefficient of thermal expansion (3 × 10⁻⁶/°C), these bricks minimize thermal stress and crack formation; 4) Chemical Inertness: Resistant to attack by acids, alkalis, and molten metals—including exhibiting a large wetting angle with molten aluminum; 5) Wear Resistance: Thanks to their high hardness (Mohs scale 9), they are ideally suited for areas subject to abrasive wear. Compared to traditional high‑alumina bricks, silicon nitride refractory bricks offer more than a 40% increase in high‑temperature strength. Physical and Chemical Specifications Typical physical and chemical specifications for silicon nitride‑bonded silicon carbide bricks include: Chemical Composition: SiC ≥ 50%, Si₃N₄ bonding phase 20–40%, impurities (Fe₂O₃ + TiO₂) < 1.5%; Physical Properties: Bulk density 2.5–3.2 g/cm³, apparent porosity 12–18%; High‑Temperature Performance: Refractoriness ≥ 1790°C, softening under load temperature ≥ 1650°C, thermal shock stability (water quenching from 1100°C) ≥ 25 cycles; Electrical Properties: Room‑temperature resistivity 10¹⁵–10¹⁶ Ω·cm, dielectric constant 9.4–9.5. Special‑purpose products, such as Sialon‑bonded bricks, must also meet specific Al₂O₃ content requirements (5–15%).

# Aluminum Silicon Carbide Bricks: The “Guardians” of High-Temperature Industries Alongside blast furnaces in steelmaking, at the scorching heart of polycrystalline silicon reduction furnaces for photovoltaics, and even within the precision chambers of semiconductor crystal growth equipment, a composite material known as “aluminum silicon carbide brick” quietly endures the harshest environmental conditions. This material—sintered through specialized processes using raw materials such as alumina (Al₂O₃), silicon carbide (SiC), and graphite (C)—has become an indispensable “guardian” in high‑temperature industrial applications, thanks to its exceptional resistance to high temperatures, corrosion, and thermal shock. ### I. Material Properties: A “Swiss Army Knife” in Extreme Heat The core strength of aluminum silicon carbide bricks lies in their unique composition and microstructure. Alumina serves as the matrix, providing high‑temperature dimensional stability and a degree of resistance to slag erosion; silicon carbide is renowned for its high hardness, superior thermal conductivity, and outstanding oxidation resistance—and with a thermal expansion coefficient that’s only half that of alumina—it effectively buffers thermal stresses. The addition of graphite further enhances the material’s resistance to permeation and thermal shock; its low thermal expansion and high thermal conductivity significantly reduce the wettability of molten slag on the brick surface. This composite structure enables aluminum silicon carbide bricks to maintain structural integrity even in environments exceeding 1600°C, with a load‑softening start temperature reaching 1640°C and a refractoriness surpassing 1770°C. Take, for example, the application in iron ladles: aluminum silicon carbide bricks must withstand dramatic temperature fluctuations—from ambient to 1400°C—during iron charging, transportation, and tapping. Their thermal shock resistance—exceeding 10 cycles in a 1100°C water‑quench test—and their exceptional erosion resistance—featuring a wear coefficient five times higher than that of phosphate‑bonded high‑alumina bricks—effectively minimize cracking and spalling, extending lining life to 2–3 times that of conventional materials. In the transition zone of cement rotary kilns, aluminum silicon carbide bricks optimize alkali‑resistance by adjusting the alumina‑silica ratio in the matrix, while fine‑tuning pore size can slow potassium vapor penetration and reduce the risk of scale formation. ### II. Manufacturing Process: The “Alchemical Art” of Precision Control The production of aluminum silicon carbide bricks represents a deep integration of materials science and engineering technology. Raw material selection must balance purity with particle size distribution: high‑alumina bauxite clinker should have an Al₂O₃ content of at least 70%, silicon carbide particles must meet a SiC purity threshold of over 93%, and graphite must strike a careful balance between flake morphology and antioxidant performance. The mixing process employs a two‑step approach—dry blending followed by wet blending—with the addition of binders such as phenolic resin or aluminum dihydrogen phosphate ensuring uniform coating of aggregate particles and preventing localized agglomeration. During forming, pressure control is exceptionally stringent: friction presses or hydraulic presses must apply sufficient pressure to tightly pack the particles, yielding a dense green body with low porosity (apparent porosity < 22%). Sintering must be carried out under reducing or protective atmospheres, where precise control of the heating curve—especially during the low‑temperature stage when binder decomposition rates are critical—and of holding time promotes strong bonding between silicon carbide particles and the matrix. For instance, one company has adopted microwave‑assisted sintering technology, shortening the traditional 72‑hour firing cycle to just 24 hours while simultaneously reducing energy consumption by 15%–20%. ### III. Application Scenarios: From Traditional Industry to High‑End Manufacturing The application landscape for aluminum silicon carbide bricks continues to expand in step with industrial upgrading. In the metallurgical sector, they have become the material of choice for critical components such as blast furnace hearths, converter trunnions, and heating furnace slides. After one steel plant upgraded its heating furnaces with aluminum silicon carbide bricks, energy consumption dropped by 8%, and annual maintenance costs were reduced by 3 million yuan. The photovoltaic industry places extremely high demands on the purity of inner linings in polycrystalline silicon reduction furnaces (metallic impurities ≤ 10 ppm), and aluminum silicon carbide bricks, with their low thermal conductivity and resistance to lithium vapor erosion, have helped boost single‑crystal silicon pulling efficiency by 12%. Applications in the semiconductor field highlight the material’s precision attributes. In crystal growth equipment, aluminum silicon carbide bricks must simultaneously meet stringent requirements such as matching thermal expansion coefficients—close to those of silicon crystals—and maintaining a porosity of less than 18%. Their ability to maintain a uniform temperature field can reduce the dislocation density of single‑crystal silicon to below 0.5 × 10⁴/cm². In the new energy vehicle sector, aluminum silicon carbide bricks are used in battery pack thermal management modules; their high thermal conductivity (150–200 W/m·K) allows for rapid dissipation of localized hotspots, reducing the risk of battery thermal runaway by 40%. ### IV. Market Trends: Dual Drivers of Green and Smart Growth The global aluminum silicon carbide brick market is undergoing structural transformation. As the world’s largest producer, China reached a capacity of 545,000 tons in 2024—but high‑end products account for less than 52% of total output, leading to structural mismatches that result in delivery cycles as long as 45–60 days. With the advancement of the “Dual Carbon” strategy, low‑thermal‑conductivity, long‑lifespan aluminum silicon carbide bricks have become a mandatory standard for electrolyzer liner upgrades, driving an estimated annual replacement demand of 63,000 tons between 2025 and 2027. On the technological front, nano‑reinforcement techniques—such as ZrB₂ modification—can increase the material’s thermal shock resistance to more than 200 cycles, while digital twin technology reduces new product development cycles by 50%. In terms of cost structure, fluctuations in silicon carbide prices—particularly green silicon carbide—have a significant impact on manufacturing costs. The adoption of life‑cycle cost (LCC) modeling is shifting the industry away from “price competition” toward “value competition”—though high‑performance bricks may carry a unit price 15%–20% higher, they can extend equipment service life to over 3,200 days while achieving overall carbon reductions of 8%–12%. From blast furnace hearths to semiconductor wafers, from traditional refractories to high‑end multifunctional composites, the evolutionary history of aluminum silicon carbide bricks reflects humanity’s ongoing quest to push the boundaries of materials science. As green manufacturing and intelligent technologies converge, this “high‑temperature guardian” is stepping forward with a lighter, smarter profile—supporting humanity’s journey toward a more efficient, lower‑energy industrial future.