Si₃N₄ 75% generally refers to the mass fraction of silicon nitride in ferro silicon nitride being about 75%. In addition to containing about 75% Si₃N₄, it also contains about 12%-17% iron (Fe), as well as a small amount of Fe₃Si, α-Fe and a very small amount of SiO₂. Silicon nitride itself is a superhard material with excellent wear resistance and compressive strength, and can be used to manufacture mechanical parts and tools working under harsh conditions.

Preparation method: Usually FeSi75 ferroalloy is used as raw material, high-purity nitrogen is introduced, and nitridation reaction is carried out at a high temperature of 1200-1400℃, and it is prepared by nitridation technology and high-temperature synthesis process.

Performance characteristics: Because it contains Si3N4 phase, it has some excellent properties of Si3N4, such as high refractoriness, good corrosion resistance, high mechanical strength, good thermal shock resistance, low thermal expansion rate, high oxidation resistance and other advantages; and because it contains Fe plastic phase, it has good sintering performance.

Ferro Silicon Nitride (Si3N4 75%)

chemical composition

	N	Si	Fe	0	Moisture	size
Ferrosilicon Nitride	28-32%	47-51%	12-17%	2.5%max	0.39%max	10-60mm
Ferrosilicon Nitride	28-32%	47-51%	14-17%	2.59%max	0.39%max	0-3mm
Other size or specification please consult us.

Component	Content Range	Core Industrial Function
Si₃N₄	75 ~ 80%	High refractoriness, anti-slag erosion, thermal shock resistance
Free Fe	12 ~ 16%	Promote sintering of refractory castables, improve compactness
Al+Ca Total	≤ 2.5%	Moderately adjust slag fluidity in blast furnace gun clay
Free Carbon	≤ 0.2%	Avoid excessive carburization of molten iron
Free Si	≤ 1%	Prevent premature violent reaction in high-temperature furnace

Metallurgical & Refractory Working Mechanisms

① Blast Furnace Taphole Clay Core Mechanism
At tapping temperature, Si₃N₄ forms dense anti-erosion film on gun clay surface; free Fe promotes continuous sintering to seal microcracks, extend tapping cycle from 8h to over 24h, reduce taphole maintenance frequency.
② Steelmaking Grain Refining Mechanism
Slowly released N element combines with V/Nb in molten steel to form nano-sized nitride precipitates, refine steel grains, improve tensile strength and fatigue resistance by 12~18%. Silicon component synchronously completes mild deoxidation to reduce oxide inclusions.
③ Refractory Castable Sintering Mechanism
Metallic iron fills crystal gaps during high-temperature sintering, improve bulk density and wear resistance of refractory linings.

Ferro Silicon Nitride (Si3N4 75%)

Industrial Application

Blast Furnace Taphole Gun Clay

The most widely used functional additive for medium & large blast furnace taphole mud. Solves rapid erosion of taphole by molten iron and slag, stabilizes tapping hole size, prolong furnace service cycle, reduce refractory consumption cost.

High-temperature Refractory Castables & Kiln Linings

Added to alumina-silica castables, furnace shelves and crucible materials, enhance thermal shock and slag resistance for steelmaking furnaces, cement kilns and glass kilns.

High-strength Nitrogen-alloyed Steel Production

Used in LF ladle refining to supply stable nitrogen source for high-strength automotive steel, engineering machinery structural steel, optimize grain structure and mechanical properties.

High-performance Ceramic Cutting Tools

Raw material for silicon nitride composite ceramics, manufacture wear-resistant cutting blades, bearing parts for aerospace and machinery industry.

Electronic Semiconductor Packaging Materials

Low-oxygen fine powder grade for high-insulation chip packaging substrates, match semiconductor thermal expansion coefficient.

FAQ

Q1: What is the core advantage of FeSiN vs pure Si3N4 powder for taphole clay?

A: FeSiN contains dispersed iron phase to boost sintering performance, price is 40~60% lower than pure silicon nitride, with equivalent anti-erosion performance for blast furnace gun clay.

Q2: Which size should I choose for blast furnace taphole mud?

A: 0-3mm fine powder for uniform mixing with clay powder; 10-60mm lump for coarse refractory aggregate formulas.

Q3: Why strictly control storage humidity below 60%?

A Silicon nitride hydrolyzes when exposed to moisture, releases ammonia gas and reduces effective nitrogen content, directly weaken taphole clay anti-scouring performance.

Q4: Do you provide test samples and customized specifications? Lead time?

A Free 1–5kg test samples available; standard stock goods 7–15 working days, customized nitrogen/particle grades 20–30 working days.

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