Aluminum Nitride Washers for Power Modules and IGBT Insulation

Aluminum Nitride Ceramic Washers Applications

• Power Electronics Modules and Inverters

  ✅Key Advantages

  1. Thermal interface upgrade
  Aluminum nitride washers can reduce local temperature rise around screw holes by several degrees compared with alumina washers due to higher thermal conductivity (170–200 W/m·K vs. 20–30 W/m·K).
  2. Compact high-voltage insulation
  Dielectric strength ≥15 kV/mm supports narrow creepage inside high-density inverter stacks while keeping threaded hardware insulated.
  3. CTE match with power chips
  CTE around 4.5×10⁻⁶/K minimizes stress between module baseplates, clamping bars and silicon or SiC devices during repeated thermal cycling.

  ✅ Problem Solved

  A power inverter OEM replaced alumina washers under high-current IGBT modules with aluminum nitride washers in a 75 kW drive platform. Thermal simulations and tests showed a 6–8°C reduction in hotspot temperature near mounting holes at continuous full load, along with a reduction in module baseplate warpage after 1,000 thermal cycles between 40°C and 120°C. Field return rate related to mounting insulation faults dropped below 0.3% over the following production year, while the mechanical design of the inverter stack remained unchanged.

• LED and UV LED Drivers / Light Engine Modules

  ✅Key Advantages

  1. Stable insulation around small screws
  Aluminum nitride washers allow secure screw fastening of LED boards to metal-core or aluminum heat sinks while maintaining electrical isolation around mounting holes.
  2. Improved junction temperature margin
  High thermal conductivity supports heat spreading from LED module islands into the surrounding hardware, improving junction temperature margin in compact light engines.
  3. Low outgassing and vacuum compatibility
  Dense aluminum nitride ceramics have low outgassing and are suitable for sealed UV modules and optical assemblies where organic insulating films are not acceptable.

  ✅ Problem Solved

  A UV LED curing system integrator added aluminum nitride washers beneath M2.5 screws that fix LED submounts to cooled housings. Compared with polymer insulators, washer replacement permitted a tighter screw torque and increased contact force without risk of creep. Measured LED junction temperature at 100% duty was reduced by approximately 4°C, and lumen maintenance at 3,000 operating hours improved by around 5%, based on internal lifetime tests on a 30-unit pilot batch.

• Industrial Power Supplies and Measurement Systems

  ✅Key Advantages

  1. Reliable insulation in high-voltage terminals
  Aluminum nitride washers provide a rigid insulating spacer around busbar bolts and terminal studs in HV power supplies.
  2. Mechanical stability in harsh duty cycles
  High flexural strength and ceramic stiffness keep bolted joints stable during vibration and temperature changes, supporting reliable calibration in measurement systems.
  3. Temperature capability beyond 200°C hardware zones
  Aluminum nitride maintains performance at elevated temperatures where polymer washers would soften or age.

  ✅ Problem Solved

  In a 40 kV test power supply, a manufacturer migrated from mica and polymer washers to aluminum nitride washers under terminal studs inside the HV compartment. Thermal tests at 120°C ambient and full voltage showed reduced drift in terminal contact resistance and stable insulation over a 1,000-hour endurance test. Service inspections after one year of field use reported no washer deformation or tracking marks, and the unit calibration interval was extended from 12 to 18 months.

AlN Washers Usage Instructions

• Installation

  1. Verify that mating metal surfaces and washer faces are clean, free from burrs and particulate before installation.
  2. Place the aluminum nitride washer flat against the mounting surface, then position the device or clamp bar on top to avoid sliding the washer under high contact pressure.
  3. Use aligned screws or studs to prevent lateral impact on the inner edge; apply torque in a controlled, cross-pattern for multi-bolt assemblies.
  4. When using thermal grease or pads, apply a thin, uniform layer and avoid excessive paste that could migrate into the washer bore.

• Use in Operation

  1. Keep clamping forces within the recommended limits of the device and fixture design to avoid point loading on washer edges.
  2. In high-frequency or pulsed power applications, periodically verify that screw torque remains within specification after initial thermal cycling.
  3. Avoid sudden temperature shocks beyond the equipment design (e.g., rapid immersion from ambient into >300°C environments) to reduce thermal shock risk.

• Storage

  1. Store aluminum nitride washers in their original trays or bags in a dry cabinet or standard warehouse environment.
  2. Avoid stacking heavy items on top of trays to prevent mechanical damage and microcracks.
  3. Keep part labels attached to each batch to trace material grade, lot and dimensions.

• Cleaning

  1. For light contamination, blow off dust with clean, dry compressed air or nitrogen.
  2. For fingerprints or light residues, use clean isopropyl alcohol with lint-free wipes and allow washers to dry fully before assembly.
  3. Avoid aggressive mechanical scrubbing or abrasive media that may introduce chips or surface scratches.

• Common Misuse and Corrective Actions

  1. Issue: Chipped inner edge from misaligned screws
  Cause: Screw or stud pushed through at an angle or with impact.
  Action: Reject visibly chipped washers, use insertion guides or pre-aligned fixtures, and train assembly to insert hardware vertically.

  2. Issue: Cracked washer after over-torque
  Cause: Torque level above design or point loading under uneven clamp.
  Action: Reduce torque to the specified range, check for flatness of mating surfaces, and avoid washers bridging significant gaps.

  3. Issue: Reduced thermal performance due to a thick grease layer
  Cause: Excess thermal compound between the washer and metal surfaces.
  Action: Clean off surplus compound and reapply a uniformly thin layer, following device manufacturer recommendations.

FAQ – Aluminum Nitride Washers

1. Q: Why choose aluminum nitride washers instead of alumina or mica washers?
   A: Aluminum nitride washers offer much higher thermal conductivity, typically 170–200 W/m·K compared with about 20–30 W/m·K for alumina, while keeping high electrical insulation, which helps reduce device temperature around mounting points.
2. Q: What thermal conductivity can be expected from aluminum nitride washers?
   A: Typical aluminum nitride washer materials provide thermal conductivity in the 170–200 W/m·K range, with some grades reaching higher values depending on purity and processing.
3. Q: How high is the dielectric strength of aluminum nitride washers?
   A: Dense aluminum nitride ceramics commonly show dielectric strength ≥15 kV/mm, making them suitable for high-voltage mounting insulation in compact layouts.
4. Q: What dimensional tolerances can aluminum nitride washers achieve?
   A: Typical machined aluminum nitride washers can reach tight OD and ID tolerances on the order of ±0.05–0.1 mm, and thickness tolerances suitable for controlled clamping force; exact limits depend on size and geometry.
5. Q: Can aluminum nitride washers be used in air at high temperatures?
   A: Aluminum nitride materials are used up to around 1,000–1,200°C in air in many designs, with material suppliers typically rating maximum service temperatures in this range for substrates and components.
6. Q: Are aluminum nitride washers compatible with vacuum and inert gas environments?
   A: Yes, aluminum nitride washers are widely used in vacuum and inert atmospheres; they maintain thermal conductivity and insulation while remaining stable under these conditions, especially when oxidation is controlled.

Aluminum Nitride Washers Reviews

• ⭐️⭐️⭐️⭐️⭐️
  We switched to aluminum nitride washers for several IGBT stacks and saw a clear improvement in temperature balance around the mounting screws. The ADCERAX team delivered the washer sizes we needed quickly and kept tolerances consistent across multiple batches.
  -- Michael Turner, Senior Power Electronics Engineer at VoltDrive Systems
• ⭐️⭐️⭐️⭐️⭐️
  Aluminum nitride washers from ADCERAX gave us a way to standardize mounting hardware across high-voltage modules without redesigning busbars. Pricing was competitive for a ceramic part and the deliveries came in line with our project schedule.
  -- Laura Schmidt, Procurement Manager at NovaTherm Industrial Electronics
• ⭐️⭐️⭐️⭐️⭐️
  We use thin aluminum nitride washers in several UV LED curing heads where board mounting space is limited. The washers helped maintain insulation and heat spreading around the fasteners and fit into our existing clamping design without changes.
  -- Kenji Sato, LED Module Design Lead at LumaTech Optoelectronics
• ⭐️⭐️⭐️⭐️⭐️
  For our high-voltage power supplies, aluminum nitride washers offered a good combination of thermal stability and dielectric margin. ADCERAX supported us with custom ID tolerances and small pilot quantities before we moved to regular production orders.
  -- Carlos Herrera, R&D Engineer – Test Systems at PowerLab Instruments