Physical Properties of Ceramics

Physical Properties of Ceramics

Reprinted with permission of the Coors Ceramics Company

The development of new ceramic materials is helping to meet the growing demand in industrial and laboratory applications. Coors ceramic components are harder, lighter, and more resistant to heat, corrosion, and wear than steel counterparts. Coors ceramic demonstrates excellent dimensional stability and can be manufactured to meet precise tolerances. Its strength and temperature resistance, combined with high resistivity and dielectric strength, make it an attractive alternative.

Chemical-Porcelain has excellent thermal-shock resistance. The chemical-porcelain used to make the products featured has a fusion point of 1670°C and a softening point of 1400°C.

High-Alumina Ceramicware made of 99.8%-pure aluminum oxide, is frequently selected by metallurgists and chemists. It is useful for applications requiring high-temperature analysis with contaminant-free results. This highly refractory labware is meant for use in reducing and oxidizing atmospheres. It can be used with refractory metals such as molybdenum, platinum, rhodium, tungsten, tantalum and iridium. It is inert in hydrogen and carbonaceous atmospheres and offers high resistance to alkalies and other fluxes at low temperatures.

High-alumina chemical tests conducted by Coors Ceramics Company using crucibles weighing approximately 32g yielded the following results:

Chemical test
Temp
Time
Wt loss
Hot conc. H2SO4
100°C
4 hrs
~6 x 10-4%
Hot 10% NaOH
100°C
4 hrs
~9 x 10-4%
Hot 50% H3PO4
90°C
4 hrs
~0.16%

Typical Ceramic Characteristics Summary

This Table Scrolls Left to Right

Physical Properties*
Chemical-porcelain
High-alumina
Maximum use temp (no load)
1400°C (2560°F ) unglazed
1150°C (2100°F) glazed
1750°C (3182°F)
Thermal-expansion coefficient
3.56 x 10-6 from 20 to 200°C
gradually increasing to
4.69 x 10-6 at 1000°C
8.0 x 10-6/°C from 25 to1000°C
Thermal shock resistance
Good
Fair
Compressive strength
-
>300,000 psi
Density (g/cc)
2.5 (typical)
3.9 (typical)
Hardness
Rockwell 45N
57.5
79
Mohs
-
9
Gas permeability
0
0
Water absorption
0
0
Maximum heating/cooling rate
200°C (392°F)/hour
150°C (302°F)/hour
Autoclavable
Up to 137°C (280°F) at 30 psi
Up to 137°C (280°F) at 30 psi
Corrosion
resistance
Acid
Good except HF
High except HF
Alkali
Good
High
Metals
Fair to good
High except Na, Li
Atmospheric
-
OK oxidizing, reducing
Advantages
Wide variety of applications,
economical
High-purity 99.8% alumina,
intended for use in oxidizing
and reducing atmospheres.
Highly refractory.
Very corrosion resistant.
*This chart is intended to illustrate typical values available from Coors Ceramics Company. Engineering data is representative. The designer should recognize that exact properties may vary according to product configuration. The information set forth is offered for comparison only, and is not to be construed as absolute engineering data or constituting a warranty or representation for which we assume legal responsibility.