Dayoo Advanced Ceramic Co.,Ltd
Dayoo Advanced Ceramic Co.,Ltd
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Silicon Nitride Ceramic (Si₃N₄) is a high-performance advanced ceramic material composed of silicon and nitrogen elements. It is manufactured through special processes like high-temperature sintering, combining a remarkable set of properties: extremely high strength, excellent toughness, outstanding thermal shock resistance, good wear resistance, and inherent electrical insulation. These characteristics make it an ideal replacement for metals and other ceramics in extremely demanding environments, earning it the reputation as an "all-round" structural ceramic.
Silicon Nitride Ceramic has extremely wide applications across various high-tech industrial fields:
Aerospace: Used for manufacturing high-temperature components such as engine bearings and turbine rotor blades.
Automotive Industry: Used for ceramic bearing balls in new energy vehicle drive motors. Its advantages like insulation, corrosion resistance, and lightweight significantly enhance motor performance and lifespan.
Mechanical Manufacturing: Used as cutting tools, ceramic rollers, wear-resistant liners, and oil-free lubrication components.
Electronics and Semiconductors: Used for heating plates, fixtures, and insulating parts in semiconductor manufacturing equipment, where its high purity and resistance to plasma erosion are crucial.
Medical Field: Used for artificial joints (e.g., hip joints), dental implants, etc., offering good biocompatibility.
High Strength and Toughness: High flexural strength and fracture toughness superior to most engineering ceramics.
Low Density and Lightweight: Density is approximately 3.2-3.3 g/cm³, only 40% that of steel, enabling effective weight reduction.
Exceptional Thermal Resistance: Retains its mechanical properties at high temperatures, with operating temperatures up to 1200°C and above.
Excellent Thermal Shock Resistance: Can withstand severe sudden temperature changes without cracking.
High Wear and Corrosion Resistance: Possesses strong resistance to erosion from most acids, alkalis, and molten metals.
Electrical Insulation: Good electrical insulation properties, suitable for high-voltage and high-frequency environments.
| Property | Unit | Typical Value Range |
|---|---|---|
| Density | g/cm³ | 3.20 - 3.30 |
| Flexural Strength | MPa | 600 - 1000 |
| Vickers Hardness | GPa | 14 - 16 |
| Fracture Toughness | MPa·m¹/² | 5 - 7 |
| Coefficient of Thermal Expansion | ×10⁻⁶/K | 3.0 - 3.2 |
| Thermal Conductivity | W/m·K | 20 - 30 |
| Maximum Use Temperature | °C | 1200 (in air) |
| Volume Resistivity | Ω·cm | >10¹⁴ |
The production of Silicon Nitride Ceramics primarily uses two main processes: Reaction Bonding (RB) and Gas Pressure Sintering (GPS):
Powder Preparation: High-purity silicon powder is nitrided to produce high-purity, ultra-fine silicon nitride powder.
Forming: The powder is mixed with binders and shaped into a "green body" of the desired form through dry pressing, isostatic pressing, or injection molding.
Sintering:
Reaction Bonding: Silicon powder green bodies are heated in a nitrogen atmosphere, where silicon directly reacts with nitrogen to form silicon nitride.
Gas Pressure Sintering: Sintering aids are added to the silicon nitride powder, and densification sintering is performed in a high-temperature, high-pressure nitrogen furnace.
Processing and Inspection: The sintered blank is precision ground and polished to achieve final dimensions and surface finish, undergoing strict non-destructive testing.
Installation: Avoid hard impacts or localized stress concentration; although tough, it remains a brittle material.
Operating Environment: Avoid prolonged contact with hydrofluoric acid (HF) and hot concentrated strong alkalis.
Temperature Changes: Despite good thermal shock resistance, it is still advisable to avoid rapid temperature changes within the allowed range.
We provide comprehensive technical support and after-sales guarantees, including: product technical consultation, usage guidance, return and replacement services for non-human-caused quality issues, and customized solutions based on customer needs.
Q1: Which is better, Silicon Nitride or Zirconia Ceramic?
A: Both have advantages. Silicon nitride excels in toughness, thermal shock resistance, and high-temperature performance, making it common for bearings and high-temperature components. Zirconia has the highest room-temperature hardness and fracture toughness and is more often used for cutting tools and dental applications.
Q2: Why are Silicon Nitride Ceramic bearings suitable for electric vehicles?
A: Because they are insulating, resistant to electrical corrosion, and lightweight. This helps avoid motor shaft current corrosion issues, increases speed and efficiency, and extends motor life.
Q3: Can Silicon Nitride Ceramic be machined?
A: Post-sintering, silicon nitride is extremely hard and can only be precision machined (e.g., grinding, drilling) using diamond tools.
