# SiAlON vs. Low Expansion Glass-ceramic

SiAlON belongs to the non-oxide engineering ceramics classification, while low expansion glass-ceramic belongs to the glass and glass-ceramics. There are 18 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 low expansion glass-ceramic.

Metric UnitsUS Customary Units

## Mechanical Properties

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

83 |

Flexural Strength, MPa | 680 | |

35 |

Knoop Hardness | 1700 | |

530 |

Poisson's Ratio | 0.23 | |

0.22 |

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

53 |

## Thermal Properties

Maximum Temperature: Mechanical, °C | 1200 | |

690 |

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

800 |

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

1.5 |

Thermal Expansion, µm/m-K | 3.6 | |

1.7 |

## Electrical Properties

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

5.7 |

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

11 |

## Otherwise Unclassified Properties

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

2.4 |

## Common Calculations

Stiffness to Weight: Axial, points | 50 | |

19 |

Stiffness to Weight: Bending, points | 67 | |

59 |

Strength to Weight: Axial, points | 16 | |

6.1 |

Strength to Weight: Bending, points | 22 | |

13 |

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

0.76 |

Thermal Shock Resistance, points | 13 | |

28 |