Papers by Keyword: Ceramic Additive

Abstract: Pure hydroxyapatite (HA) was obtained by the calcination of calf femoral bone and was ground manually and by subsequent mechanical grinding to decrease the particle size. Micron-sized Al₂O₃, ZrO₂, and TiO₂ ceramics were added at different concentrations (5, 10 and 15 wt. %) to the obtained micron-sized HA powder. After adequate mixing cylindrical test specimen were prepared and sintered at 900, 1000 and 1100 °C. The specimen were tested for their compressive strengths and SEM observations and XRD analyses were conducted to determine the effect of different additives and sintering temperatures on the mechanical strengths, morphology and formed phases of the samples. TiO₂ addition to the HA at 15 wt. % powder resulted in highest compressive strength with good sintering behavior.

Abstract: Two kinds of ceramic additives have been developed that one is the serpentine particles and another is a blend of serpentine particles and catalyst. The tribological properties of the addition of different additives are investigated through a series of friction and wear experiments. Wear surface and the composition of the tribofilm were examined by SEM, EDS and XPS. In case of single serpentine additive, tribo-film can be formed gradually on the worn metal surface. The friction coefficient is about 0.11. The tribofilm mainly consists of Mg and Si elements transferred from the additive. This can compensates part of wear mass loss, avoids the direct contact of the two rubbing surfaces, and thus effectively improves the anti-wear characteristics. In case of the blend oil additive, the tribo-film formed obviously on the worn surface in the initial stage and no obvious film at end of the test. However, the friction coefficient can lower even to 0.007~0.008 compared with the above experiment. The worn surface becomes very smooth. Chemical analysis shows that there is a very thin film of carbon concentration with thickness of 30~50nm on the worn surface. Existence of the very thin carbon-concentrated film and mirror-like surface generates super low friction coefficient.