# SiAlON vs. Fused Silica

SiAlON belongs to the non-oxide engineering ceramics classification, while fused silica belongs to the glass and glass-ceramics. There are 21 material properties with values for both materials. Properties with values for just one material (7, in this case) are not shown.

For each property being compared, the top bar is SiAlON and the bottom bar is fused silica.

Metric UnitsUS Customary Units

## Mechanical Properties

Compressive (Crushing) Strength, MPa | 2620 | |

1100 |

Elastic (Young's, Tensile) Modulus, GPa | 290 | |

73 |

Flexural Strength, MPa | 680 | |

67 |

Knoop Hardness | 1700 | |

570 |

Poisson's Ratio | 0.23 | |

0.17 |

Shear Modulus, GPa | 120 | |

31 |

Tensile Strength: Ultimate (UTS), MPa | 190 | |

50 |

## Thermal Properties

Maximum Temperature: Mechanical, °C | 1200 | |

1080 |

Specific Heat Capacity, J/kg-K | 880 | |

720 |

Thermal Conductivity, W/m-K | 19 | |

1.4 |

Thermal Expansion, µm/m-K | 3.6 | |

0.5 |

## Electrical Properties

Dielectric Constant (Relative Permittivity) At 1 MHz | 9.3 | |

3.8 |

Dielectric Strength (Breakdown Potential), kV/mm | 8.3 | |

30 |

Electrical Resistivity Order of Magnitude, 10^{x} Ω-m |
14 | |

14 |

## Otherwise Unclassified Properties

Density, g/cm^{3} |
3.3 | |

2.2 |

## Common Calculations

Stiffness to Weight: Axial, points | 50 | |

18 |

Stiffness to Weight: Bending, points | 67 | |

63 |

Strength to Weight: Axial, points | 16 | |

6.3 |

Strength to Weight: Bending, points | 22 | |

14 |

Thermal Diffusivity, mm^{2}/s |
6.4 | |

0.85 |

Thermal Shock Resistance, points | 13 | |

97 |