ONLY DIAMONDS ARE HARDER
For aluminium oxide ceramics, ceramic raw materials with an Al 2 O 3 content of more than 80% are used (as high-quality wear protection, in general only ceramics with an Al 2 O 3 content of at least 92%) should be used).
It is essentially a single-phase, single-component oxide of corundum crystals, which are bonded by solid-state reactions during sintering.
Aluminium oxide is one of the hardest engineering materials and currently the most technically and economically important representative of oxide ceramic materials.
Densely sintered it is characterized by:
• High degree of strength and hardness
• Resistant to high temperatures and corrosion
MANUFACTURE AND PROPERTIES
The starting point for the production process is a very pure, synthetic (alpha) aluminium oxide in powder form. The higher the Al 2 O 3 content, the better the mechanical values and the lower the glass phase will be. This leads to an even higher density and to a higher wear resistance.
The casting process:
• Pressing (highest wear resistance)
• Slip casting (demanding geometries)
These processes produce the so-called “green bodies” whose consistency is similar to that of chalk. They can now be machined with conventional machines by turning or sawing to obtain specific contours or dimensions. The subsequent sintering process takes place at approximately 1560°C, after which the parts are connected and no longer have any porosity. The resistance values remain virtually unchanged up to 1000°C.
APPLICATIONS
Due to their high hardness and temperature resistance, aluminium oxide ceramic products are used in extreme wear conditions, often associated with high operating temperatures. The availability in very low wall thicknesses makes thin-walled wear protection coatings possible, especially where weight or construction restrictions prevent the installation of a thicker wall thickness.
The wide variety of products allows the coating of all parts subject to heavy wear and high temperatures, such as separators, bunkers, diffusers, sprayers, hydrocentrifuges, chain conveyors, cones, mixers, pumps, chutes, pipes, chutes, gutters or cyclones.