Precision Ceramics, a division of McGeoch Technology, is a company dedicated to the engineering of technical ceramics. From procurement and supply through to technical design and specialist machining, we offer a complete service.
Our reputation for quality and service is truly international with specialist ceramic components engineered by Precision Ceramics finding their way into an ever-widening array of worldwide applications in industries as diverse as aerospace, opto-electronics and nuclear power.
Macor Machinable Glass Ceramic
Macor is an outstanding engineering material and is machinable with ordinary metalworking tools. Macor is also a problem solving material combining the performance of a technical ceramic with the versatility of a high performance plastic.
Macor has a high use temperature (800°C continuous to 1,000°C peak). It has a low thermal conductivity and is a useful high temperature insulator as well as an excellent electrical insulator. Macor has no porosity and when properly baked out, will not outgas. It is strong and rigid and, unlike high temperature plastics, will not creep or deform. Macor is also radiation resistant.
Macor is pure white and can be highly polished. It can be thick or thin film metallised, brazed and epoxy bonded. Another major advantage of this unique material is that, even in small quantities, components are economical to manufacture.
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Mechanical Properties of Macor Machinable Glass Ceramic
The mechanical properties of Macor machinable glass ceramic is outline in the following table.
Table 1. Mechanical properties of Macor machinable glass ceramic
|
Properties
|
Metric
|
Imperial
|
|
Density
|
2.52 g/cm3
|
157 lbs/ft3
|
|
Porosity
|
0%
|
0%
|
|
Young’s Modulus, 25°C
(Modulus of Elasticity)
|
66.9 GPa
|
9.7x106psi
|
|
Poisson’s Ratio
|
0.29
|
0.29
|
|
Shear Modulus, 25°C
|
25.5GPa
|
3.7x106psi
|
|
Hardness, Knopp, 100g
|
250
|
250
|
|
Hardness, Rockwell A
|
48
|
48
|
|
Modulus of Rupture, 25°C
(Flexural Strength)
|
94 MPa
|
13,600psi
|
|
Compressive strength
|
345 MPa
|
50,000 psi
|
|
Fracture Toughness
|
1.53 MPa m0.5
|
1,390 psi in0.5
|
Thermal Properties of Macor Machinable Glass Ceramic
The thermal properties of Macor machinable glass ceramic is outline in the following table.
Table 2. Thermal properties of Macor machinable glass ceramic
|
Coefficient of Expansion
|
|
|
|
-200 - 25°C
|
74x10-7/°C
|
41x10-7/°F
|
|
25 - 300°C
|
93x10-7/°C
|
52x10-7/°F
|
|
25 - 600°C
|
114x10-7/°C
|
63x10-7/°F
|
|
25 - 800°C
|
126x10-7/°C
|
70x10-7/°F
|
|
Specific Heat, 25°C
|
.79 KJ/kg°C
|
0.19 Btu/lb°F
|
|
Thermal Conductivity, 25°C
|
1.46 W/m°C
|
10.16 Btu in hr ft2°F
|
|
Thermal Diffusivity, 25°C
|
7.3x10-7m2/s
|
0.028 ft2/hr
|
|
Continuous Operating Temperature
|
800°C
|
1,472°F
|
|
Maximum No Load Temperature
|
1,000°C
|
1,832°F
|
Chemical Properties of Macor Machinable Glass Ceramic
The chemical properties of Macor machinable glass ceramic is outline in the following table.
Table 3. Chemical properties of Macor machinable glass ceramic
|
Tests
|
Results
|
|
Solution
|
pH
|
Time
|
Temp
|
Gravimetric
|
|
5% HCL
(Hydrochloric Acid)
|
0.1
|
24 hrs
|
95°C
|
~ 100
|
|
0.002 HNO3
(Nitric Acid)
|
2.8
|
24 hrs
|
95°C
|
~ 0.6
|
|
0.1 NaHCO3
(Sodium Bicarbonate)
|
8.4
|
24 hrs
|
95°C
|
~ 0.3
|
|
0.02 Na2CO3
(Sodium Carbonate)
|
10.9
|
6 hrs
|
95°C
|
~ 0.1
|
|
5% NaOH
(Sodium Hydroxide)
|
13.2
|
6 hrs
|
95°C
|
~ 10
|
|
Resistance to water
over time
H2O
|
7.6
|
1 day*
|
95°C
|
0.01
|
|
3 days*
|
95°C
|
0.07
|
|
7 days*
|
95°C
|
9.4
|
|
3 days**
|
95°C
|
0.06
|
|
6 days**
|
95°C
|
0.11
|
*Water not freshened daily **Water freshened daily
|
Electrical Properties of Macor Machinable Glass Ceramic
The electrical properties of Macor machinable glass ceramic is outline in the following table.
Table 4. Electrical properties of Macor machinable glass ceramic
|
Dielectric Constant, 25°C
|
Metric
|
Imperial
|
|
1 KHz
|
6.03
|
6.03
|
|
8.5 GHz
|
5.67
|
5.67
|
|
Loss Tangent, 25°C
|
|
|
|
1 KHz
|
4.7x10-3
|
4.7x10-3
|
|
8.5 GHz
|
7.1x10-3
|
7.1x10-3
|
|
Dielectric Strength (AC) average
(at 12 mil thickness and 25°C)
|
9.4 KV/mm
|
785 V/mil
|
|
Dielectric Strength (DC) average
(at 12 mil thickness and 25°C)
|
62.4 KV/mm
|
5,206 V/mil
|
|
DC Volume Resistivity, 25°C
|
>1016 ohm-cm
|
>1016 ohm-cm
|
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This information has been sourced, reviewed and adapted from materials provided by Precision Ceramics.
For more information on this source, please visit Precision Ceramics.