Silicon Nitride
Silicon Nitride (Si3N4)
Silicon nitride (Si3N4) has the most comprehensive combination of mechanical, thermal and electrical properties among all advanced ceramic materials. It is a high-performance advanced ceramic with extremely high hardness and outstanding thermal shock resistance and impact resistance. Its high-temperature resistance far exceeds that of most metals, and it also has excellent creep resistance and oxidation resistance.
Material Advantages
- High strength over a large temperature range
- High fracture toughness
- Good flexural strength
- Mechanical fatigue and creep resistant
- Lightweight – Low density
- High hardness and wear resistance, both impingement and frictional modes
- Superior thermal shock resistance
- Low thermal expansion
- Electrical insulator
- Good oxidation resistance
- Good chemical corrosion resistance
- Wear-resistant
- High stiffness
Material grade
PCSN1000
PCSN2000
PCSN3000
PCSN4000
PCSN1000 – Gas Over-Pressure Sintered
This is the most popular method for producing high-strength and complex geometry silicon nitride components. This method uses a silicon nitride powder that has been mixed with sintering aids to promote liquid phase sintering (typically yttria, magnesium oxide, and/or alumina) as well as binders to improve the mechanical strength of the green ceramic body. The powder is pressed into the desired form and green-machining can take place. The parts are then placed into a furnace that has a pressurized nitrogen atmosphere to aid with densification and prevent the evaporation/decomposition of the silicon, nitrogen, and additives.
Precision Ceramics stocks a range of standard silicon nitride ceramic rods, which are all precision turned to an excellent surface finish. These rods can be used as bearings, pistons, engine components, or in a variety of other assemblies. In addition, Precision Ceramics offers full machining/grinding services for custom silicon nitride component manufacturing.
Precision Ceramics stocks a range of standard silicon nitride ceramic rods, which are all precision turned to an excellent surface finish. These rods can be used as bearings, pistons, engine components, or in a variety of other assemblies. In addition, Precision Ceramics offers full machining/grinding services for custom silicon nitride component manufacturing.
Applications
- Aerospace applications
- Chemical plant engineering and construction
- Engine wear parts
- Foundry applications
- Mechanical engineering
- Medical components
PCSN2000 – Hot Pressed
HPSN is produced by uniaxially pressing silicon nitride powder with sintering additives while applying heat at the same time. This process requires a special type of press and die. It produces a silicon nitride with excellent mechanical properties. However, only simple shapes can be produced. Because it is impossible to green-machine a component that is hot-pressed, diamond grinding is the only way to create complex geometries. Because of the high costs and difficulties associated with diamond grinding and hot-pressing, its use is typically limited to the production of simple components in small quantities.
Applications
- Aerospace applications
- Chemical plant engineering and construction
- Engine wear parts
- Foundry applications
- Mechanical engineering
- Medical components
PCSN3000 – Hot Isostatic Pressed
This method consolidates the silicon nitride powder by using high pressures and high temperatures. A silicon nitride body with closed porosity is isostatically pressed (uniform pressure on all sides) via an inert gas at up to 2000 bar while the chamber is simultaneously heated. This process effectively squeezes any pores/defects from the material while it is sintering and brings the density closer to theoretical. HIPing improves the mechanical properties and reliability, however, it is an expensive process that is typically only used in very select circumstances.
Applications
- Aerospace applications
- Bearing applications
- Chemical plant engineering and construction
- Engine wear parts
- Foundry applications
- Mechanical engineering
- Medical components
PCSN4000 – Extruded Gas Over-Pressure Sintered
This method uses a silicon nitride powder that has been mixed with sintering aids to promote liquid phase sintering (typically yttria, magnesium oxide, and/or alumina) as well as binders to improve the mechanical strength of the green ceramic body.
Precision Ceramics stocks a range of standard silicon nitride ceramic rods, which are all precision ground to an excellent surface finish. These rods can be used as bearings, pistons, engine components, or in a variety of other assemblies. In addition, Precision Ceramics offers full machining/grinding services for custom silicon nitride component manufacturing.
Precision Ceramics stocks a range of standard silicon nitride ceramic rods, which are all precision ground to an excellent surface finish. These rods can be used as bearings, pistons, engine components, or in a variety of other assemblies. In addition, Precision Ceramics offers full machining/grinding services for custom silicon nitride component manufacturing.
Applications
- Aerospace applications
- Bearing applications
- Chemical plant engineering and construction
- Engine wear parts
- Foundry applications
- Mechanical engineering
- Medical components
Material Properties
Mechanical Properties
Thermal Properties
Electrical Properties
| Property | Unit | PCSN1000 | PCSN2000 | PCSN3000 | PCSN4000 |
|---|---|---|---|---|---|
| Density | g/cm3 | 3.18-3.40 | 3.18-3.40 | 3.18-3.26 | 3.23 |
| Compressive Strength | MPa | 3000 | 3000 | 3000 | 3000 |
| Flexural Strength @ 25°C | MPa | 730 | 970 | 760-830 | 850 |
| Weibull-Modulus m | – | 18 | 20 | 12 | 18 |
| Fracture Toughness KIc | MPa m1/2 | 7 | 6.2 | 6.2-6.5 | 8.5 |
| Young‘s Modulus | GPa | 300 | 300 | 300-310 | 320 |
| Poisson’s Ratio | – | 0.26 | 0.26 | 0.26 | 0.28 |
| Hardness | GPa | 15 | 15 | 15.3-15.6 | 16 |
| Property | Unit | PCSN1000 | PCSN2000 | PCSN3000 | PCSN4000 |
|---|---|---|---|---|---|
| Thermal Conductivity @ 20°C | W/mK | 25 | 24 | 25 | 28 |
| Thermal Shock Parameter R1 | K | 558 | 748 | 590-620 | 700 |
| Thermal Shock Parameter R2 | W/m | 14 | 18 | 15 | 19 |
| CTE1 25°C ➞ 250°C | 10-6/K | 1.9 | 1.9 | 1.9 | 1.9 |
| CTE1 25°C ➞ 1000°C | 10-6/K | 3.2 | 3.2 | 3.2 | 3.2 |
| Maximum Temperature (Inert) 2 | °C | 1400 | 1400 | 1400 | 1400 |
| Maximum Temperature (Oxidizing) 2 | °C | 1200 | 1200 | 1200 | 1200 |
| Property | Unit | PCSN1000 | PCSN2000 | PCSN3000 | PCSN4000 |
|---|---|---|---|---|---|
| Thermal Conductivity @ 20°C | W/mK | 25 | 24 | 25 | 28 |
| Thermal Shock Parameter R1 | K | 558 | 748 | 590-620 | 700 |
| Thermal Shock Parameter R2 | W/m | 14 | 18 | 15 | 19 |
| CTE1 25°C ➞ 250°C | 10-6/K | 1.9 | 1.9 | 1.9 | 1.9 |
| CTE1 25°C ➞ 1000°C | 10-6/K | 3.2 | 3.2 | 3.2 | 3.2 |
| Maximum Temperature (Inert) 2 | °C | 1400 | 1400 | 1400 | 1400 |
| Maximum Temperature (Oxidizing) 2 | °C | 1200 | 1200 | 1200 | 1200 |
Silicon Nitride Machining
Silicon nitride can be processed in a green, billet, or fully dense state. In the raw or billet state, it can be relatively easily processed into complex geometric shapes. However, the sintering process required to fully densify the material will result in a shrinkage of approximately 20% in the silicon nitride body. This shrinkage means that very strict tolerances cannot be maintained when processing silicon nitride before sintering. In order to achieve very strict tolerances, diamond tools must be used to process/grind fully sintered materials. This process uses very precise diamond coated tools/grinding wheels to grind materials until the desired shape is formed.
Product application
Electrical performance
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Forming method
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