High-Performance Silicon Nitride Ceramics For Industrial Needs High Hardness And Thermal Insulation

High-Performance Silicon Nitride Ceramics for Industrial Needs High Hardness and Thermal Insulation

Introduction
Silicon Nitride (Si₃N₄) ceramic is a high-performance advanced ceramic material produced by high-temperature sintering of silicon nitride powder. It is renowned for its unique combination of properties, including extremely high hardness, outstanding fracture toughness, excellent thermal insulation (low thermal conductivity), and remarkable thermal shock resistance. This material excels in extreme environments, making it an ideal choice for addressing needs related to wear resistance, thermal insulation, and lightweighting in many high-end industrial fields.

Applications
Leveraging its hardness and thermal insulation properties, silicon nitride ceramics are widely used across various high-tech sectors:

• High-Temperature Insulation Components: Used as kiln insulation linings and thermocouple protection tubes in metallurgy and glass industries, effectively reducing heat loss and withstanding high temperatures.

• Wear-Resistant Sealing Applications: Serve as mechanical seal rings for pumps, especially in high-temperature and highly corrosive media, where their hardness and wear resistance ensure long life and reliability.

• Aerospace: Used in engine components and combustion chamber liners, utilizing their high-temperature resistance, thermal insulation, and lightweight (compared to metals) properties.

• Electronics Industry: Used as paddles and rollers in diffusion furnaces and CVD equipment for semiconductor manufacturing, where their high purity and thermal insulation prevent contamination and heat transfer.

• Military Protection: Used in transparent armor and ballistic ceramics, as their high hardness effectively resists impact.

Advantages

1. High Hardness and Wear Resistance: High Vickers hardness, second only to a few materials, with extremely excellent wear resistance and long service life.

2. Excellent Thermal Insulation (Low Thermal Conductivity): Thermal conductivity is much lower than metals, making it an excellent high-temperature insulating material that effectively blocks heat transfer, saving energy and reducing consumption.

3. High Strength and High Toughness: Fracture toughness is several times that of alumina ceramics, with excellent resistance to mechanical shock and thermal shock, and less prone to brittle fracture.

4. High-Temperature and Corrosion Resistance: Maintains strength at high temperatures up to 1200°C and has good resistance to most acids and alkalis.

5. Low Density and Self-Lubrication: Lightweight, reducing system load, and with a low friction coefficient for smoother operation.

Specifications Table

Manufacturing Process
Nitridation of high-purity silicon powder → Obtain silicon nitride powder → Add sintering aids → Ball milling and mixing → Spray granulation → Dry pressing/Cold isostatic pressing (CIP) → Gas pressure sintering (GPS) or Hot pressing (HP) → Precision machining (diamond grinding) → Non-destructive testing → Finished product inspection.

Usage Instructions

1. Pre-Installation: Check the ceramic component for defects such as cracks or chipped edges. Although it has relatively good toughness, it is still a brittle material and should be protected from rough impact.

2. During Installation: Ensure even force application. For seals, use specialized tools to tighten bolts uniformly to prevent damage from unilateral stress.

3. Operation: Although it has good thermal shock resistance, it is still advisable to avoid sudden and severe temperature changes to extend its service life.

4. Maintenance: Regularly inspect the system status. If abnormal wear or performance degradation is found, investigate and replace promptly.

After-Sales Service
We provide professional technical consultation and selection support. The product warranty period is 12 months. Custom non-standard sizes are supported, and detailed product performance test reports and usage guidance are provided. We承诺 (commit to) free repair or replacement for issues caused by material or manufacturing defects.

FAQ
Q1: Which is harder, silicon nitride ceramic or alumina ceramic?
A1: The Vickers hardness of silicon nitride ceramic (HV 1400-1600) is slightly lower than that of high-purity alumina ceramic (HV 1600+), but its fracture toughness is much higher than alumina, giving it greater overall resistance to damage and better impact resistance.

Q2: Is its thermal insulation performance better than zirconia ceramic?
A2: No. Zirconia ceramic has very low thermal conductivity (~2-3 W/m·K) and is an excellent thermal insulator. The thermal conductivity of silicon nitride (15-25 W/m·K) is higher than zirconia but still significantly lower than metals, placing it in the category of thermal insulating materials, while its mechanical strength is much higher than zirconia.

Q3: Why is it much more expensive than alumina ceramic?
A3: The main reasons are high raw material costs and complex sintering processes. Silicon nitride powder is difficult to produce and requires high-temperature sintering under high-pressure nitrogen atmosphere, resulting in high equipment investment and energy consumption costs.