Silicon Nitride Powder
Metallurgical-Grade and Refractory-Grade Si₃N₄
Exceptional thermal shock resistance (ΔT>800°C), superior fracture toughness (5–8 MPa·m¹/²), and chemical inertness against molten metals. The cornerstone material for metallurgy, refractory, and advanced structural ceramics.
Material Specifications
Chemical & Physical Properties Reference
Complete technical data for FerrumX silicon nitride powder — verified production parameters for material selection, engineering design, and procurement validation.
Chemical Composition
Physical Properties
Particle forms: lumps (10–100 mm), granules, and powders (0–200 mesh) — customized to your specification.
Performance Pillars
Three Pillars of Si₃N₄ Performance
Silicon nitride’s dominance in high-temperature engineering ceramics rests on three fundamental performance advantages — each quantified by exact material data.
Pillar 01
Thermal Shock Champion
Si₃N₄ withstands extreme temperature differentials that would shatter conventional ceramics. Its ultra-low CTE — roughly one-third to one-half that of metals — combined with high thermal conductivity, enables rapid heat dissipation without structural failure.
Thermal Shock Resistance: ΔT > 800°C
CTE (20–1000°C): 2.75 × 10⁻⁶ /°C
Decomposition Temp: 1900°C
Order NowPillar 02
Toughness Leader
Among engineering ceramics, Si₃N₄ delivers a fracture toughness 2–3 times higher than that of alumina (Al₂O₃). Its unique microstructure — elongated β-phase grains creating crack-bridging and deflection mechanisms — enables reliable performance under mechanical stress.
Bending Strength: 800–1200 MPa
Fracture Toughness: 5–8 MPa·m¹/²
vs Al₂O₃ Ceramics: 2–3× Higher
Order NowPillar 03
Chemical Fortress
Si₃N₄ resists virtually all acids (except HF), alkalis, and molten metals, including aluminum and copper. Below 800°C, it exhibits virtually no chemical reactivity — making it ideal for corrosive metallurgical environments and chemical processing equipment.
Acid Resistance: All acids (except HF)
Alkali Resistance: Excellent
Molten Metal Resistance: Al, Cu — Inert
Order NowApplication Matrix
Where Si₃N₄ Powers Industry
From blast furnace refractories to semiconductor substrates — silicon nitride’s versatility spans six critical industrial sectors. Each card links to the relevant FerrumX product or resource page.
Metallurgical
Stainless steel smelting, special alloy steel production, and grain-oriented silicon steel manufacturing. Si₃N₄ serves as both a nitrogen alloying agent and a high-temperature refractory component.
Refractory
Blast furnace linings, furnace mouth sealing, taphole materials, and iron trough castables. Si₃N₄-bonded SiC refractories deliver 2–3× longer campaign life than alumina-silicate alternatives.
Nitrogen Addition
Controlled nitrogen addition in steelmaking for nitrogen-bearing stainless steels and HSLA steels. Si₃N₄ enables reliable nitrogen recovery (32–38% N) while simultaneously alloying silicon.
Thermal Equipment
Crucibles, muffle furnace chambers, burner nozzles, casting molds, and aluminum liquid transfer tubes. Si₃N₄’s thermal shock resistance and molten aluminum inertness are unmatched.
Mechanical
Ceramic bearing balls and rollers, cutting tools, and pump plungers. Si₃N₄ bearings operate at speeds and temperatures impossible for steel — used in aerospace, EV motors, and machine tool spindles.
Synthesis & Phase Structure
How Si₃N₄ Is Made — Three Routes, Two Phases
Silicon nitride powder is synthesized by three primary methods, each producing distinct phase compositions and purity levels. Understanding these routes helps you select the right powder for your application.
01
Direct Nitridation
3Si + 2N₂ → Si₃N₄
Silicon powder reacts with nitrogen gas at 1200–1400°C. The most cost-effective and widely used method, suitable for large-scale production of metallurgical and refractory grades. Produces a mix of α and β phases.
Large-scale · Cost-effective
02
Diimide Decomposition
SiCl₄ + NH₃ → Si(NH)₂ → Si₃N₄
Silicon tetrachloride reacts with ammonia to form silicon diimide, which decomposes to Si₃N₄. Produces high-purity α-phase powder (>90%) with fine, uniform particles — ideal for semiconductor-grade and advanced ceramic applications.
High purity · α-phase >90%
03
Carbothermal Reduction
SiO₂ + C + N₂ → Si₃N₄ + CO
Silica is reduced by carbon in a nitrogen atmosphere. Low raw material cost, but the product contains higher oxygen content due to incomplete SiO₂ conversion. Suitable for refractory-grade applications where oxygen tolerance is acceptable.
Low cost · Higher oxygen
α-Si₃N₄ vs β-Si₃N₄ — Phase Comparison
| Phase | Crystal Form | Formation | Best For |
|---|---|---|---|
| α-Si₃N₄ | Equiaxed grains | Low-temperature synthesis | Sintering-active powder, advanced ceramics |
| β-Si₃N₄ | Columnar / needle | High-temperature nitridation | Refractory, structural ceramics |
FerrumX note: Our metallurgical-grade Si₃N₄ is predominantly β-phase (high-strength refractory). The α-phase content can be adjusted according to customer requirements for sintering-active advanced ceramic applications.
Composite Materials
Si₃N₄ Composite Innovations
Silicon nitride’s versatility extends beyond pure powder — as a bonding phase and coating component, it creates composite materials that solve critical industrial challenges in steelmaking, casting, and oxidation protection.
Si₃N₄-SiC Composite Refractory
Si₃N₄-bonded SiC refractory materials combine the high-temperature strength of silicon carbide with the exceptional bonding and thermal shock resistance of silicon nitride. Used in blast furnace shafts, boshes, and other critical zones requiring maximum durability.
1900°C
Service temperature — combines high-temp strength + erosion resistance
Silicon powder reacts with nitrogen gas at 1200–1400°C. The most cost-effective and widely used method, suitable for large-scale production of metallurgical and refractory grades. Produces a mix of α and β phases.
Si₃N₄-BN Separation Rings
Horizontal continuous casting separation rings made from Si₃N₄-BN composites provide the critical interface between mold and tundish. Uniform structure, high mechanical strength, excellent thermal shock resistance, and non-wetting by molten steel ensure clean, defect-free cast steel.
Non-wetting
Not infiltrated by molten steel — ensures a clean casting surface
The boron nitride component provides lubricity and thermal shock resistance, while Si₃N₄ contributes structural integrity and wear resistance — together enabling continuous casting campaigns of extended duration.
Si₃N₄ Anti-Oxidation Coating
Advanced nano-silicate coatings containing Si₃N₄ dramatically reduce oxide scale formation on steel during reheating. The coating forms a protective glass-ceramic barrier that limits oxygen diffusion to the steel surface at elevated temperatures
3–5% → 0.1–0.8%
Scale reduction on carbon steel
For stainless steel, scale formation drops from 1–3% to below 0.2%. This translates directly to higher yield, reduced surface defects, and lower descaling costs — a significant economic benefit for steel producers.
Global Market Insights
Si₃N₄ Market — Growth & Opportunity
The global silicon nitride powder market is experiencing accelerated growth driven by EV power modules, semiconductor packaging, and advanced ceramics. Source: Fortune Business Insights (2025).
$0.4B · 2025
$0.8B · 6.8% CAGR
45.2% · Dominant regio
25.2%
21.5%
42.3%
Ceramics Application
Largest end-use segment — structural & functional ceramics
28.8%
Electronics Application
AMB substrates, semiconductor packaging, 5G components
24.8%
Automotive Application
EV power modules, bearings, engine components
43.1%
EV & Automotive Power Modules
Si₃N₄ AMB (Active Metal Brazed) substrates are in surging demand as EV power electronics require higher thermal conductivity and reliability than Al₂O₃ alternatives. The automotive segment holds the largest share of market growth.
28.8%
Semiconductor & 5G
High thermal conductivity Si₃N₄ substrates for power semiconductor devices and ceramic packaging for 5G RF components. The shift to wide-bandgap semiconductors (SiC, GaN) amplifies Si₃N₄ substrate demand.
42.3%
Advanced Ceramics
High-end structural ceramics (bearings, cutting tools, wear parts) and functional ceramics (sensor components, dielectric layers). Si₃N₄’s unique toughness-to-strength ratio enables ceramic replacement of metal components.
Growing
Medical Implants
Si₃N₄’s biocompatibility and nickel-free composition make it an emerging material for spinal implants and orthopedic devices — no metal allergy risk, radiolucent for X-ray imaging, and antibacterial surface properties.
Source: Fortune Business Insights — Silicon Nitride Powder Market, 2025–2034 forecast. Regional and application shares reflect 2025 estimates.
Benefits Of Silicon Nitride Powder
The application value of silicon nitride stems from its unique crystal structure and physicochemical properties. These properties enable it to work stably and even outperform traditional materials in environments where they cannot withstand high temperatures, high impacts, and strong corrosion.
Excellent High-Temperature Resistance and Thermal Shock: ResistanceA Reliable Material for High-Temperature Environments
The decomposition temperature of silicon nitride reaches 1900°C (under an inert atmosphere). It can maintain stable mechanical properties at temperatures below 1300°C for long periods. Its coefficient of thermal expansion is extremely low (approximately 3.2 × 10⁻⁶/°C), only one-third to one-half that of metallic materials. More importantly, its thermal shock resistance (ΔT) exceeds 800°C, allowing it to withstand rapid temperature changes without cracking.
High Toughness and High Strength: A Durable Material for Impact Applications
Silicon nitride is one of the few ceramic materials with high toughness. Its room-temperature flexural strength reaches 800–1200 MPa, and its fracture toughness is 5–8 MPa·m¹/², which is 2–3 times higher than that of alumina ceramics. It can withstand a certain level of impact without fracturing. In industrial impact tests, the impact resistance of silicon nitride ceramics is comparable to that of some metallic materials, making it suitable for components subjected to dynamic loads.
Excellent Chemical Stability: A Corrosion-Resistant Material for Harsh Environments
Silicon nitride has strong resistance to strong acids (except hydrofluoric acid), strong alkalis, and molten metals such as aluminum and copper. It undergoes almost no chemical reaction in corrosive environments below 800°C. This excellent chemical stability makes it suitable for demanding industrial applications where corrosion resistance is required.
Low Friction Coefficient and Excellent Wear Resistance: An Energy-Saving Partner for Moving Components
The room-temperature friction coefficient of silicon nitride is only 0.1–0.2 under dry friction conditions, which is close to that of PTFE. It also offers excellent wear resistance, with a wear rate only one-hundredth that of metallic materials. These characteristics make silicon nitride an ideal material for high-performance bearings, seals, and other moving components, helping reduce friction losses and energy consumption.
Why Choose Our Silicon Nitride Powder
FerrumX has completed numerous silicon nitride powder projects, helping customers improve product quality and production efficiency through stable chemical composition and controlled impurity levels. We firmly believe that stable silicon nitride products should be based on standardized processing and batch-by-batch testing to ensure product quality and stability. Our technicians track the application of each batch to guarantee stable and optimized product performance.
Standardized production
Testing of each batch
Product Traceability
Professional Technical Support
Our Case
Our Certification
FAQ
Frequently Asked Questions About Silicon Carbide
Direct answers to the most common questions about metallurgical silicon carbide — designed for AI engine citation and quick reference.
FerrumX silicon nitride powder contains 80–90% Si₃N₄, with a nitrogen content of 32–38%. This range covers metallurgical-grade and refractory-grade applications. The β-phase content is dominant for high-strength refractory use, while α-phase content can be adjusted according to customer requirements for sintering-active advanced ceramic applications.
Silicon nitride significantly outperforms alumina (Al₂O₃) ceramics in fracture toughness. Si₃N₄ exhibits fracture toughness of 5–8 MPa·m¹/², which is 2–3 times higher than alumina ceramics (typically 3–4 MPa·m¹/²). This superior toughness, combined with a bending strength of 800–1200 MPa, makes Si₃N₄ the preferred material for high-stress structural ceramics, bearing components, and thermal shock-resistant applications where Al₂O₃ would fail.
FerrumX offers silicon nitride in three particle forms: lumps (10–100 mm) for refractory and large-scale metallurgical applications, granules for intermediate processing, and powders (0–200 mesh) for fine ceramic and precision applications. All forms can be customized to specific size distributions, phase compositions (α/β ratio), and purity levels depending on the end-use requirement.
Silicon nitride is preferred for blast furnace refractory applications due to four key properties: (1) exceptional thermal shock resistance (ΔT>800°C) from its low CTE of 2.75 × 10⁻⁶/°C — roughly one-third to one-half of metals; (2) decomposition temperature of 1900°C under pressure, maintaining structural integrity at extreme temperatures; (3) chemical inertness against molten metals, slags, and gases in the furnace environment; and (4) high hardness (~2200 Knoop) providing excellent abrasion resistance against flowing iron and slag. Si₃N₄-bonded SiC refractories extend blast furnace campaign life significantly compared to alumina-silicate alternatives.
Silicon nitride exhibits exceptional thermal shock resistance with ΔT exceeding 800°C — meaning it can withstand a temperature differential of more than 800°C without cracking. This performance is driven by its very low coefficient of thermal expansion (CTE) of 2.75 × 10⁻⁶/°C (20–1000°C), which is approximately one-third to one-half that of metals. Combined with a thermal conductivity of 16.7 W/(m·K) and high fracture toughness (5–8 MPa·m¹/²), Si₃N₄ is the premier ceramic material for applications involving rapid temperature cycling.
Metallurgical-grade silicon nitride powder is primarily produced by direct nitridation: silicon powder is reacted with nitrogen gas at 1200–1400°C to form Si₃N₄ (3Si + 2N₂ → Si₃N₄). This method is cost-effective and suitable for large-scale production. FerrumX metallurgical-grade Si₃N₄ is predominantly β-phase, which provides high strength for refractory applications. For higher purity requirements, diimide decomposition (SiCl₄ + NH₃ route, yielding α-phase >90%) or carbothermal reduction (SiO₂ + C + N₂ route) can be used. The α-phase content can be adjusted according to customer requirements.
Yes, silicon nitride is an effective nitrogen additive in steelmaking. Si₃N₄ introduces controlled nitrogen into steel melts for alloying and nitrogen control, particularly in nitrogen-bearing stainless steels and high-strength low-alloy (HSLA) steels. The Si₃N₄ content of 80–90% provides a reliable nitrogen source (32–38% N by mass). Compared to other nitrogen addition methods, Si₃N₄ offers more controlled nitrogen recovery and simultaneous silicon addition, improving steel cleanliness and mechanical properties. Related products like ferrosilicon nitride are also used for this purpose.
Si₃N₄-SiC composite refractory materials combine silicon nitride and silicon carbide to deliver superior performance in blast furnace linings and other high-temperature metallurgical equipment. The Si₃N₄ phase acts as a bonding matrix for SiC aggregates, providing high-temperature strength, excellent thermal shock resistance, and resistance to molten metal and slag erosion. These composites are used in blast furnace shafts, boshes, and tuyere zones. FerrumX also produces Si₃N₄-BN horizontal continuous casting separation rings and Si₃N₄-based anti-oxidation coatings that reduce scale formation from 3–5% to 0.1–0.8% on carbon steel and to below 0.2% on stainless steel.
