#### Reaction Bonded Silicon Nitride (RBSN)

Thermal reaction of silicon metal compacts and nitrogen produces Reaction Bonded Silicon Nitride. Complex components can be readily and economically produced by machining the material in the green state. RBSN is a moderately dense form of Silicon Nitride that does not contain a glassy second phase and therefore maintains its mechanical properties to 1400°C. Molten metal (non-ferrous) processing applications are ideal for RBSN because of excellent corrosion resistance and price performance relationships.

#### Reaction Bonded Silicon Nitride (RBSN) – Properties (Typical)*

Property | Value |
---|---|

Type | |

Bulk Desity | 2.4-2.6 g/cm^{3} |

Porosity (volume percent) | 25-18 |

Flexural Strength (MOR) @ RT, 4 point average | 289-338 MPa 42-49 ksi |

Elastic Modulus (E) | 160-179 GPa 23-26 Mpsi |

Poisson's Ratio (v) | 0.23-0.24 |

Fracture Toughness (whiskers) | 3.0-3.6 |

Thermal Shock Resistance (▵T_{c}) | 400-500°C |

*Properties vary dependent upon green forming technique

#### “PAD” Silicon Nitride-SC

“PAD” Silicon Nitride-SC is a zero porosity, specially formulated silicon nitride material for use in the semiconductor industry. The material is 98% SiN with 2% densification additives. The additives are nonalkaline metals.

#### “PAD” Silicon Nitride-SC – Properties (Typical)

| |
---|---|

Bulk Density | 3.15 g/cm^{3} |

Flexural Strength (MOR) @RT, 4 point average | 100 ksi |

Elastic Modulus (E) | 46 Mpsi |

Hardness (Knoop 1 kg) | 1480 kg/mm^{2} |

Thermal Expansion (RT-1000°C) | 3.4 10^{-6}/°C |

Thermal Conductivity (RT) | 30.0 W/m*K |

#### PAD” Silicon Nitride SC-1

The SC (semiconductor) grade is a fully dense, highly pure form of silicon nitride. Sinteririg aid content is minimized to maintain purity and is selected for compatibility with the extreme environments associated with Si wafer processing. Sizes up to 500mm square or 730mm round are possible with PAD (Pressure Assisted Densification) processmg and the resultant products exhibit uniformly excellent mechanical properties.

#### “PAD” Silicon Nitride SC-1 – Properties (Typical)

Property | Value |
---|---|

Bulk Desity | 3.18 g/cm^{3} |

Average Grain Size | .50 µm |

Flexural Strength (MOR) @ RT, 4 point average | 640 MPa 93 ksi |

Characteristic Strength @ RT, 4 point | 675 MPa 98 ksi |

Weibull Modulus (m) | 9 |

Elastic Modulus (E) | 310 GPa 45 Mpsi |

Poisson's Ratio (v) | 0.27 |

Hardness (Knoop 1 kg) | 1560 kg/mm^{2} |

Fracture Toughness (Vickers) | 5.7 MPa*m^{1/2} |

Thermal Expansion (RT-1000°C) | 3 3 10^{-6}/°C |

Thermal Conductivity (RT) | 30.0 W/m*K |

#### PSG Silicon Nitride

PSG Silicon Nitride is a fully dense, pressureless sintered ceramic specifically compounded to yield an amorphous intergranular phase. Pressureless sintering allows for net shape forming of complex components in a cost effective manner. This grade is isotropic with respect to engineering properties and offers excellent resistance to mechanical fatigue. PSO Si3N4 is useful for both large shaped, large cross-sectional structures as well as small, intricate components.

#### PSG Silicon Nitride – Properties (Typical)

Property | Value |
---|---|

Bulk Density | 3.25 g/cm^{3} |

Flexural Strength (MOR) @ RT, 4 point average | 689 MPa 100 ksi |

Characteristic Strength @ RT, 4 point | 730 MPa 106 ksi |

Weibull Modulus (m) | 15 |

Elastic Modulus (E) | 303 GPa 44 Mpsi |

Poisson's Ratio (v) | 0.24 |

Hardness (Knoop 1 kg) | 1450 kg/mm^{2} |

Fracture Toughness (Vickers) | 5.7 MPa*m^{1/2} |

Thermal Expansion (RT-1000°C) | 3.3 10^{-6} |

Thermal Conductivity (RT) | 29.5 W/m*k |

Thermal Shock Resistance (▵T_{c}) | 675°C |

#### PSX Silicon Nitride

PSX is a fully dense, isotropic grade of Silicon Nitride offering excellent wear resistance and improved elevated temperature properties. Pressureless sintering allows for net shape forming of complex components for a wide variety of structural applications. Through exact control of processing and chemistry, the grain boundary or intergranular phase is engineered to be crystalline in PSX Si3N4. Heat engine components are an excellent application for this material.

#### PSX Silicon Nitride – Properties

| |
---|---|

Bulk Density | 3.27 g/cm^{3} |

Flexural Strength (MOR) @ RT, 4 point average | 703 MPa 102 ksi |

Characteristic Strength @ RT, 4 point | 744 MPa 108 ksi |

Weibull Modulus (m) | 14 |

Characteristic Strength @ RT, 4 point | 641 MPa 93 ksi |

Elastic Modulus (E) | 317 GPa 46 Mpsi |

Poisson's Ratio (v) | 0.24 |

Hardness (Knoop 1 kg) | 1480 kg/mm^{2} |

Fracture Toughness (Vickers) | 6.0 MPa*m^{1/2} |

Thermal Expansion (RT-1000°C) | 3.4 10^{-6} |

Thermal Conductivity (RT) | 30.0 W/m*k |

Thermal Shock Resistance (▵T_{c}) | 700°C |