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★ Flagship Material · BLK Series
Si3N4

Our most-shipped ceramic —
built for thermal shock and cyclic loading.

Silicon nitride is Ceramitell's flagship material. The BLK series Si₃N₄ hot surface igniter reaches service temperature in 3 seconds and survives 100,000+ ignition cycles — proven across our 180,000-unit/year Italian pellet stove OEM partnership. Industry-default substrate for thermal cycling applications.

100K+
Cycle Life
3 sec
Heat-Up Time
3.2
Thermal Expansion
7.5
Fracture K (MPa·m½)
Certifications & Standards
ISO 9001IATF 16949CERoHS · REACHUL Recognized
01 · Material Properties

Si₃N₄ by the numbers.

Property values below are typical for our standard Si₃N₄ production grades. Our HIP-processed (Hot Isostatic Pressed) grades approach 99.5% theoretical density — used for the highest-precision bearing balls and cutting tools.

PropertyUnitStandardHIP-ProcessedIgniter Grade
Densityg/cm³3.203.253.20
Hardness (HV)Vickers150016001450
Flexural StrengthMPa9001100850
Fracture ToughnessMPa·m½7.58.07.0
Max Service Temp°C140013001400
Thermal ConductivityW/m·K283022
Thermal Expansion (RT–1000°C)×10⁻⁶/K3.23.23.4
Thermal Shock ResistanceΔT °C9009501000
Dielectric StrengthkV/mm121311
Lower thermal expansion = better thermal shock resistance. Si₃N₄ has the lowest of all our ceramics.
02 · 4 Production Grades

One material, four optimized recipes.

Each Si₃N₄ grade tunes sintering aids and process parameters for a specific application family. Igniter grade prioritizes thermal cycling; HIP grade prioritizes density and strength; structural grade prioritizes machinability.

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Igniter Grade — BLK Series

Optimized for 100,000+ thermal cycles. Used in pellet stove, BBQ, gas furnace, and HVAC hot surface igniters. UL/CE certified across 12V–230V. Heat-up to service temperature in 3 seconds.

Best for → Hot surface igniters · glow plugs
Bearing Grade — HIP-Processed

Hot Isostatic Pressed for void-free density (99.5% theoretical). The premium grade for precision balls (G3 grade) and high-RPM hybrid bearings. Roundness ≤0.08 μm, surface Ra ≤0.02 μm.

Best for → Precision balls · hybrid bearings
⚙️
Structural Grade

Optimized for machinability and cost-effective custom geometry production. Used for shafts, turbines, lift tubes, and custom-machined components. Tolerance ±0.005 mm achievable.

Best for → Shafts · turbines · structural · custom
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Cutting Grade

High-speed cutting tool blanks for cast iron and superalloy machining. Higher hardness (HV 1600) and edge retention than alumina ceramic inserts. Stock blank or custom insert geometry.

Best for → Cutting tool blanks · machining inserts
04 · When to Choose Si₃N₄

Si₃N₄ vs. the alternatives.

Silicon nitride is the thermal-shock champion of our materials. Pick it when thermal cycling or high-RPM bearing loads matter — otherwise alumina is more cost-effective for static or low-cycle service.

Pick Si₃N₄ when…

Si₃N₄ wins
  • Thermal shock cycling — Thermal expansion 3.2 × 10⁻⁶/K, 2.5× lower than alumina. The default for igniters that fire 100K+ times.
  • High-RPM bearings — Density 3.2 g/cm³, 60% lighter than steel = less centrifugal load. Default for hybrid bearings above 18,000 RPM.
  • Cyclic mechanical loading — Fracture toughness 7.5 MPa·m½ + Weibull modulus 15+ = predictable fatigue life.
  • Custom geometry needed — Machinability before sintering enables complex shapes that aren't feasible in SiC.
  • Cutting tools for cast iron — Better hot hardness than alumina inserts at high cutting speeds.

Reach for something else when…

Other materials
  • Cost is the driver — Use Al₂O₃ — half the price for static wear and insulation
  • Service temp above 1400°C — Use Al₂O₃ (1700°C) or SiC (1600°C)
  • Maximum impact resistance — Use ZrO₂ — fracture K 10 vs Si₃N₄ 7.5
  • Maximum hardness — Use SiC: HV 2800 vs Si₃N₄ 1500 for extreme abrasion
  • Highest thermal conductivity — Use AlN: 170 W/m·K for power electronics
★ Engineering Case · Italian Pellet Stove OEM

From −38% warranty returns to a 7-year supply partnership.

Our longest-running OEM partner switched from a European competitor's alumina igniters to our Si₃N₄ BLK series in 2018. They ship 180,000 units/year, and warranty returns dropped 38% in the first 12 months. Now in year 7 of supply.

Switch Outcome · Year 1
Al₂O₃ → Si₃N₄ outcome
  • −38% Warranty returns vs prior alumina
  • −32% Cold-start failures (sub-zero installs)
  • +22% Average igniter service life
  • 180K/yr Current OEM production volume
05 · Engineering FAQ

The questions engineers ask.

Direct answers from our application team. Email engineering@ceramitell.com with your drawing or duty cycle for a deeper dive.

Why does Si₃N₄ outperform alumina in hot surface igniters?
Thermal shock resistance. Alumina's thermal expansion (8 × 10⁻⁶/K) is 2.5× higher than Si₃N₄'s (3.2). Over 100K+ heating/cooling cycles, alumina develops microcracks; Si₃N₄ doesn't. Our BLK series has 7+ years of OEM field data confirming this.
What's HIP-processing and when do I need it?
Hot Isostatic Pressing — densifies Si₃N₄ to 99.5% of theoretical density by applying 100–200 MPa argon pressure at sintering temperature. Required for high-precision balls (G3–G5) and aerospace structural parts. Not needed for igniters or general structural use.
Can your Si₃N₄ igniters match Norton/Coorstek part numbers?
Yes — our BLK series is designed for drop-in replacement of legacy alumina and Si₃N₄ igniters from major Western suppliers. Send the part number or drawing, we'll reply within 48 hours with DFM feedback and quote. UL/CE certified.
What's the max RPM for Si₃N₄ ball bearings?
Hybrid bearings (Si₃N₄ balls + steel rings) routinely run 60,000+ RPM. Full Si₃N₄ bearings can run higher but cost ~3× as much — used only in extreme service like high-speed dental drills, vacuum-deposition spindles, and aerospace gyroscopes.
How are Si₃N₄ samples packaged for shipment?
Igniters: individual blister pack inside antistatic bags, cushioned outer carton. Precision balls: vacuum-sealed precision packaging with desiccant, lot certs in pouch. Custom structural: foam-cradled inside dimensional shipping crate. We've shipped to 42 countries — zero in-transit breakage 2024.
Do you sign NDA before reviewing custom Si₃N₄ designs?
Yes — mutual NDAs are standard before reviewing proprietary drawings or duty cycles. Our template is available on request, or we can sign yours after legal review (typically 2–3 business days).