Machinable Glass-ceramic vs. PBI
Machinable glass-ceramic and PBI belong to fundamentally different material chemistries. Machinable glass-ceramic is a ceramic material, while PBI is polymeric. Therefore, their performance will be even more dissimilar than would be suggested by the difference in properties. There are 19 material properties with values for both materials. Properties with values for just one material (15, in this case) are not shown. Please note that the two materials have significantly dissimilar densities. This means that additional care is required when interpreting the data, because some material properties are based on units of mass, while others are based on units of area or volume.
For each property being compared, the top bar is machinable glass-ceramic and the bottom bar is PBI.
Mechanical Properties
| Compressive (Crushing) Strength, MPa | 310 | |
| 350 |
| Elastic (Young's, Tensile) Modulus, GPa | 67 | |
| 5.9 |
| Flexural Strength, MPa | 96 | |
| 220 |
| Tensile Strength: Ultimate (UTS), MPa | 84 | |
| 160 |
Thermal Properties
| Maximum Temperature: Mechanical, °C | 760 | |
| 340 |
| Specific Heat Capacity, J/kg-K | 790 | |
| 930 |
| Thermal Conductivity, W/m-K | 1.2 | |
| 0.41 |
| Thermal Expansion, µm/m-K | 21 | |
| 23 |
Electrical Properties
| Dielectric Constant (Relative Permittivity) At 1 Hz | 6.0 | |
| 3.4 |
| Dielectric Constant (Relative Permittivity) At 1 MHz | 6.4 | |
| 3.8 |
| Dielectric Strength (Breakdown Potential), kV/mm | 27 | |
| 23 |
| Electrical Resistivity Order of Magnitude, 10x Ω-m | 14 | |
| 13 |
Otherwise Unclassified Properties
| Density, g/cm3 | 2.7 | |
| 1.3 |
Common Calculations
| Stiffness to Weight: Axial, points | 14 | |
| 2.5 |
| Stiffness to Weight: Bending, points | 51 | |
| 46 |
| Strength to Weight: Axial, points | 8.8 | |
| 34 |
| Strength to Weight: Bending, points | 16 | |
| 50 |
| Thermal Diffusivity, mm2/s | 0.56 | |
| 0.34 |
| Thermal Shock Resistance, points | 4.3 | |
| 84 |