Materials Synthesis and Development

Group

Sub-µm Al2O3 ceramics for wear components

Topic

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Submicrometer Aluminium oxide tool ceramic (average grain size 0.56 µm).

verschleißteile1

Decreasing the grain size gives pure, chemically and thermally stable α-Al2O3 (corundum) with a similarly high hardness as Al2O3/TiC composites.

verschleissteile2

Minimum wear of new sub-µm corundum ceramics in different environments.

Sub-µm and nanotechnologies for components associating highest hardness and wear resistance with an extreme thermal and chemical stability

Known components made of hardmetals, Si3N4 or TiC-reinforced composites exhibit a limited stability in agressive environments because of metallic, glassy or oxidizing constituents, Zirconia ceramics are less hard and their microstructure and strength critically depend on the temperature. The new sub-µm corundum ceramics (Fig. 1) avoid these shortcomings, and their hardness surpasses all grades addressed above.


Advantages
 

  • Extremely high hardness (Fig. 2)
  • Significantly improved wear resistance (Fig. 3)
  • Reduced aging in aqueous media compared with advanced commercial grades of sintered corundum (Fig. 4)
  • High strength (600-850 MPa), nearly constant up to about 1000 °C
  • High chemical stability in acids, bases, and agressive gases.



Subcritical crack velocity of sub-µm Al2O3 ceramics in water and in air compared with conventional grades: evidence of an outstanding high reliability of the new sub-µm ceramics in aqueous media.


Products and services offered
 

  • Development of high-purity ceramics on the basis of corundum (α-Al2O3) with sub-µm/nano microstructures for wear resistant components
  • Alternative development with commercial or with nanoscale raw materials
  • Technological investigations for upscaling supporting the development of new products; screening of raw materials and shaping approaches
  • Investigations of the technical performance in various applications