Jun 7 2002
Chemical Formula
46% SiO2,16% Al2O3, 7% B2O3, 10% K2O, 17% MgO
Topics Covered
Background
Mechanical Properties
Thermal Properties
Electrical Properties
Chemical Properties
Background
Typical properties for Macor are given in the tables below.
Mechanical Properties
| Property |
Value |
| Density |
2.52 g/cm3 |
| Porosity |
0% |
| Young’s Modulus (@ 25 °C) |
66.9 GPa |
| Poissons Ratio |
0.29 |
| Shear Modulus (@ 25 °C) |
25.5 GPa |
| Hardness – Knoop (100 g) |
250 |
| Hardness – Rockwell A |
48 |
| Modulus of Rupture (@ 25 °C) |
94 MPa |
| Compressive Strength |
345 MPa |
| Fracture Toughness |
1.53 MPa.m-½ |
Thermal Properties
| Property |
Value |
Co-Efficient of Thermal Expansion
-200 – 25 °C
25-300 °C
25-600 °C
25-800 °C |
74x10-7/°C
93x10-7/°C
114x10-7/°C
126x10-7/°C |
| Specific Heat |
0.79 kJ/kg.°C |
| Thermal Conductivity (@ 25 °C) |
1.46 W/m.°C |
| Thermal Diffusivity (@ 25 °C) |
7.3x10-7m2/s |
| Continuous Operating Temperature |
800 °C |
| Maximum No Load Temperature |
1000 °C |
Electrical Properties
| Property |
Value |
Dielectric Constant (@ 25 °C)
1 kHz
8.5 GHz |
6.03
5.67 |
Loss Tangent (@ 25 °C)
1 kHz
8.5 GHz |
4.7x10-3
7.1x10-3 |
Dielectric Strength (AC average)
12 mm thickness and 25 °C |
9.4 kV/mm |
Dielectric Strength (DC average)
12 mm thickness and 25 °C |
62.4 kV/mm |
| DC Volume Resistivity (@25 °C) |
>1016 ohm.cm |
Chemical Properties
| Solution |
PH |
Time |
Temp. |
Wt Loss
(mg/cm2) |
| 5% Hydrochloric Acid (HCl) |
0.1 |
24 hrs |
95 °C |
~100 |
| 0.002 M Nitric Acid (HNO3) |
2.8 |
24 hrs |
95 °C |
~0.6 |
| 0.1 M Sodium Bicarbonate (NaHCO3) |
8.4 |
24 hrs |
95 °C |
~0.3 |
| 0.02 M Sodium Carbonate (Na2CO3) |
10.9 |
6 hrs |
95 °C |
~0.1 |
| 5% Sodium Hydroxide (NaOH) |
13.2 |
6 hrs |
95 °C |
~10 |
| Resistance to water over time |
7.6 |
1 day*
3 days*
7 days*
3 days†
6 days† |
95 °C
95 °C
95 °C
95 °C
95 °C |
0.01
0.07
9.4
0.06
0.11 |
* water not refreshed daily
† water refreshed daily
Primary author: AZoM.com