High-Temperature Silicon Nitride Ceramic Gaskets and Seals: Sealing Solutions for Extreme Environments

Introduction

Silicon Nitride ceramic gaskets and seals are precision components manufactured from high-performance silicon nitride (Si₃N₄) material. They are specifically designed to operate in extremely harsh conditions, combining exceptional mechanical strength, outstanding thermal shock resistance, and stable chemical inertness. In applications involving high temperature, high pressure, strong corrosion, and severe wear, traditional metal or polymer seals are prone to failure, whereas silicon nitride ceramic seals provide reliable and long-lasting sealing performance, making them the preferred choice for high-end industrial equipment.

Applications and Uses

• Semiconductor Manufacturing Equipment: Used for tube sealing, door sealing, and gas nozzle sealing in CVD, PECVD, diffusion furnaces, etc., offering resistance to plasma erosion and high purity.

• Automotive Turbochargers: Serve as sealing rings and thrust washers for turbochargers, withstanding high-temperature exhaust gases (up to 900°C and above) and high-speed rotation.

• High-Temperature Industrial Furnaces: Used for viewport sealing, door sealing, and thermal connection insulation in vacuum sintering furnaces and atmosphere-protected furnaces.

• Chemical and Pump Valves: Act as mechanical seal rings and gaskets for corrosion-resistant pumps, valves, and reactors, resisting strong acids, alkalis, and molten salts.

• Aerospace: Used for critical high-temperature sealing parts in engines and related auxiliary systems.

Advantages and Characteristics

• Extreme High-Temperature Resistance: Can operate long-term at up to 1200°C in oxidizing atmospheres and withstand even higher temperatures short-term with minimal creep.

• Excellent Thermal Shock Resistance: Capable of enduring rapid temperature changes during equipment heating and cooling without cracking, ensuring high reliability.

• Superior Wear Resistance: High hardness and low friction coefficient give it a much longer service life than metal materials when used as seals or gaskets.

• Outstanding Corrosion Resistance: Offers excellent resistance to most acids, alkalis, and molten metals, with exceptional chemical stability.

• Low Density and High Rigidity: Lightweight, reduces centrifugal force in high-speed rotating components, while maintaining high strength and dimensional stability.

Specifications Parameter Table

Manufacturing Process

1. Powder Preparation: High-purity, ultra-fine silicon nitride powder is uniformly mixed with appropriate sintering aids.

2. Forming: Depending on shape complexity, green bodies are formed by dry pressing, cold isostatic pressing (CIP), or injection molding (MIM).

3. Sintering: Densification is achieved in a high-temperature sintering furnace (pressureless sintering or gas pressure sintering) under a nitrogen atmosphere to form high-density ceramic bodies.

4. Precision Machining: Sintered parts are precision ground, lapped, and polished using diamond grinders to ensure dimensional accuracy (up to μ-level) and surface finish.

5. Inspection: 100% dimensional inspection is performed, and non-destructive testing such as ultrasonic or X-ray inspection can be conducted as required.

Usage Instructions

• Installation: Ensure contact surfaces are clean and flat. Tighten bolts evenly and symmetrically to avoid cracking due to uneven force.

• Mating Materials: It is recommended to pair with high-hardness wear-resistant materials (such as tungsten carbide, hard alloys, or itself) for optimal performance.

• Temperature Control: Although it has good thermal shock resistance, it is still advisable to heat up and cool down as steadily as possible during startup and shutdown.

• Precautions: Avoid direct contact with hydrofluoric acid (HF) and hot concentrated phosphoric acid.

After-Sales Service

We provide professional technical consultation and sealing solution design support. Products come with a quality guarantee, and we offer comprehensive after-sales follow-up services to assist customers in resolving application issues.

FAQ (Frequently Asked Questions)

Q1: What is the difference between silicon nitride ceramic seals and alumina ceramic seals?
A: Silicon nitride has far superior toughness, thermal shock resistance, and fracture strength compared to alumina, making it more reliable under mechanical impact and sudden temperature changes, but it is also more expensive. Alumina is more suitable for relatively stable operating conditions.

Q2: Can non-standard sizes and shapes of gaskets be customized?
A: Yes. We support customized production and machining according to customer drawings to meet various special application requirements.

Q3: How to determine if a silicon nitride seal has failed?
A: The main signs include a significant increase in equipment leakage rate, inability to maintain system pressure, or visible wear powder or cracks at the sealing部位 (location). Regular scheduled maintenance and replacement are recommended.