Ceramics-Silikáty 51, (1) 30 - 39 (2007) |
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THE EFFECT OF SURFACE FINISH AND CAVITATING LIQUID ON THE CAVITATION EROSION OF ALUMINA AND SILICON CARBIDE CERAMICS
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Nour Wagdy Mokthar Naguib 1, Dulias Ulrike 2, Schneider Johannes 2,
Zum Gahr Karl-Heinz 2
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1 National Research Centre, Department of Refractories, Ceramics and Building Materials, Cairo, Dokki, Egypt
2 Universität Karlsruhe (TH), Institut für Werkstoffkunde II, Germany
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Keywords: Ceramics, Structural materials, Cavitation
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The cavitation erosion of alumina (F 99.7, Friatec) and sintered silicon carbide (SSiC, EKasic F) with different surface finish
was investigated at 25°C for up to 6h in distilled water as a cavitating liquid according to ASTM G32-92. The wear
progress was followed by measuring the cumulative mass and volume losses. The eroded surfaces were examined for their
damaged microstructure using SEM. The wear resistance of the tested ceramics, in terms of the incubation time and mass and
volume losses, was improved when decreasing surface roughness. SSiC showed higher wear resistance in comparison with
alumina. The results were discussed in terms of the hardness, fracture toughness, grain size, surface roughness and
microstructure. In addition, the influence of oils as cavitating liquids on the erosion of tested ceramics was studied. The
results indicated that water is highly erosive medium when compared with the used oils as a result of higher water vapour
pressure, lower viscosity and higher density |
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