M3 to M12 Threaded Silicon Nitride Screws Nuts Bolts – Si₃N₄ Insulating Fasteners up to 1000 °C

Applications: Silicon Nitride Screws, Nuts, and Bolts

• Vacuum and Heat Treatment Furnaces

  ✅Key Advantages

  1. Stable clamping up to 900–1000 °C
  Silicon nitride screws and bolts keep clamping force in heating zones where steel fasteners soften, supporting long-duration cycles.
  2. Low particle generation inside the hot zone
  The ceramic surfaces generate fewer metal particles and avoid red-scale flakes, supporting cleaner furnace environments for sensitive alloys.
  3. Thermal shock-tolerant joints
  Si₃N₄ fasteners withstand rapid temperature changes up to several hundred degrees per cycle, limiting cracking when fixtures move between hot and cooler zones.

  ✅ Problem Solved

  A heat treatment OEM upgraded metallic fixture hardware to silicon nitride screws and nuts in a vacuum furnace line operating around 900 °C with repeated quenching. Previously, fixture realignment and bolt replacement were needed after roughly 250–300 cycles due to creep and oxidation. After switching to Si₃N₄ bolts on critical joints, fixture maintenance intervals extended beyond 900 cycles, reducing unplanned downtime by over 60 % and lowering annual fixture-related service cost by several tens of thousands of dollars across multiple furnaces.

• Chemical Processing and Corrosive Cleaning Systems

  ✅Key Advantages

  1. Resistance to many acids and alkalis
  Silicon nitride nuts and bolts maintain mechanical integrity in aggressive solutions where stainless steel fasteners suffer pitting or stress corrosion cracking.
  2. Non-contaminating hardware near sensitive fluids
  The ceramic surfaces help reduce metal ion contamination into process liquids, important for high-purity chemical lines.
  3. Extended fastener lifetime in hot chemical baths
  In heated baths, Si₃N₄ fasteners reduce replacement frequency, stabilizing the clamping of supports, covers and inline fixtures.

  ✅ Problem Solved

  A chemical equipment integrator used silicon nitride screws and nuts to fix support frames and covers in a hot acid cleaning station running at approximately 80–90 °C. Stainless fasteners previously required replacement every few months due to corrosion and seized threads, and disassembly sometimes damaged the plastic and composite parts they clamped. After converting the key joints to Si₃N₄ fasteners, inspection intervals were extended to annual shutdowns, thread seizure incidents nearly disappeared and the number of unplanned maintenance interventions related to fasteners dropped to near zero over a full production year.

• Test Fixtures, R&D Equipment and Automotive Test Rigs

  ✅Key Advantages

  1. Dimensionally stable under repeated thermal cycles
  Silicon nitride screws hold calibration-critical fixtures in position across many heating and cooling cycles, supporting repeatable test results.
  2. Electrically insulating fasteners in high-voltage setups
  Non-conductive Si₃N₄ bolts and nuts separate live conductors from grounded structures without adding extra insulating spacers.
  3. Lightweight components in moving assemblies
  The lower density of silicon nitride compared with metallic high-temperature alloys reduces inertia in rotating or reciprocating test components.

  ✅ Problem Solved

  An automotive test lab introduced silicon nitride screws and nuts in a high-temperature exhaust test rig where sensors and sample holders were located close to heated sections. Previous metal hardware caused short circuits and measurement drift over long cycles due to oxidation films and leakage currents. By replacing specific joints with Si₃N₄ fasteners, the lab combined mechanical clamping and insulation in a single component, reducing the number of separate insulators and metallic brackets. Across a 6-month campaign of repeated tests, the number of wiring-related reworks fell sharply and the time spent on fixture re-adjustment per test series dropped by about 30 %.

Si3N4 Screws, Nuts, and Bolts Usage Instructions

• Installation

  1. Use matching ceramic or soft metal washers between silicon nitride bolt heads/nuts and the clamped component to distribute load.
  2. Apply torque gradually with a calibrated wrench; avoid impact tools and sudden torque spikes on ceramic fasteners.
  3. Align threads carefully; ensure at least two full rotations by hand before applying torque to prevent cross-threading.
  4. Follow torque values defined by your design team; if no values are available, start with 40–60 % of the torque used for an equivalent steel fastener and adjust based on clamp load measurements.

• Use in Service

  1. Avoid bending loads directly on the exposed portion of silicon nitride screws and bolts; design joints so that load is carried mainly in tension and compression.
  2. In thermal cycling equipment, allow sufficient clearance for differential expansion between Si₃N₄ fasteners and surrounding metallic structures.
  3. For vacuum or clean applications, keep contact surfaces free of debris before final tightening to minimize particle generation.

• Storage

  1. Store silicon nitride screws, nuts and bolts in partitioned trays or compartment boxes to avoid ceramic-on-ceramic impact.
  2. Keep products dry and free from abrasive contaminants; avoid stacking heavy metal parts directly on top of ceramic fasteners.
  3. Maintain clear identification of sizes and drawing numbers on outer packaging for traceability.

• Cleaning

  1. For general cleaning, use non-abrasive cloths and neutral detergents; rinse with clean water and dry completely before reuse.
  2. Avoid strong alkaline cleaners that may attack certain ceramic compositions over long exposure times; follow your process compatibility data.
  3. Do not use sandblasting or aggressive mechanical brushing directly on ceramic threads, as this may introduce micro-cracks.

• Common Misuse Points and Simple Fixes

  1. Issue: Fastener fractures during tightening
  Likely cause: Impact tool use or torque value set close to steel fastener levels.
  Corrective action: Switch to controlled torque tightening, reduce target torque, add washers to increase bearing area and review design safety factor for Si₃N₄.

  2. Issue: Threads chip at the start of engagement
  Likely cause: Misalignment between bolt and nut or presence of hard particles in threads.
  Corrective action: Introduce lead-in chamfers, ensure hand-start assembly, clean threads before use and avoid reusing any part that shows visible chipping on the lead threads.

  3. Issue: Crack lines visible at the under-head fillet after long service
  Likely cause: Local stress concentration due to sharp fillets or tilted bearing surface under the head.
  Corrective action: Use a larger washer or support ring, specify a smooth radius under the head during design and check flatness of the clamped surface.

FAQ – Silicon Nitride Ceramic Screws, Nuts, and Bolts

1. Q: What are silicon nitride screws, nuts and bolts used for?
   A: Silicon nitride screws, nuts and bolts are used where joints must stay mechanically strong under high temperature, corrosion and electrical insulation requirements, such as vacuum furnaces, chemical equipment and test rigs.
2. Q: How hot can silicon nitride screws and bolts run in service?
   A: Typical silicon nitride fasteners are selected for continuous service temperatures around 800–1000 °C, with short-term peaks up to about 1200 °C in suitable atmospheres, depending on design and grade.
3. Q: Are silicon nitride nuts and bolts electrically insulating?
   A: Yes, silicon nitride screws, nuts and bolts are electrically insulating and are often used where metal fasteners would create leakage paths or arcing risks near live components.
4. Q: Can silicon nitride screws replace all metal fasteners in my equipment?
   A: Silicon nitride fasteners are usually applied at critical positions where temperature, corrosion or insulation requirements are beyond the capability of metal bolts; they are not intended to replace every standard steel fastener in a system.
5. Q: What thread standards are available for silicon nitride screws and bolts?
   A: Silicon nitride screws and bolts can be supplied in common metric threads such as M3–M12 and selected inch threads (UNC/UNF), and custom thread forms can be machined based on drawings.
6. Q: How are silicon nitride screws tightened without damaging them?
   A: Installers should start threads by hand, use a torque wrench instead of impact tools and set torque values lower than steel equivalents, following torque guidelines adjusted for ceramic properties.

Customer Reviews – Silicon Nitride Screws, Nuts, and Bolts

• ⭐️⭐️⭐️⭐️⭐️
  We introduced silicon nitride screws and nuts into several vacuum furnace fixtures where stainless bolts were deforming after repeated cycles. The new Si₃N₄ fasteners kept their geometry through long runs and made fixture maintenance more predictable.
  -- Michael Hart – Engineering Manager, ThermoForge Furnaces GmbH
• ⭐️⭐️⭐️⭐️⭐️
  On our hot acid cleaning module, metal bolts on structural brackets were a constant maintenance item. After switching to silicon nitride screws and bolts, we saw a clear drop in fastener-related interventions, and the joint design stayed unchanged, which made the upgrade easy to implement.
  -- Laura Kim – Process Engineer, NovaChem Process Systems
• ⭐️⭐️⭐️⭐️⭐️
  We use silicon nitride screws, nuts and stud bolts on a high-temperature dynamometer rig. The fasteners handle the thermal cycles and provide electrical insulation to the sensor mounts, which helped simplify the fixture design.
  -- Daniel Ruiz – R&D Test Lab Supervisor, Axis Motion Technologies
• ⭐️⭐️⭐️⭐️⭐️
  Our customers in vacuum heat treatment and chemical equipment projects often request tailored silicon nitride screws and nuts. Being able to order custom Si₃N₄ fasteners per drawing with controlled tolerances has supported both sample projects and follow-up batch orders.
  -- Emily Zhang – Purchasing Specialist, ADCERAX Advanced Ceramics