Alumina-bearing component

Table 1 Uses of Alumina Solid alumina Furnace components Catalyst substrates Electronics substrates Electrical insulators Cutting tools Bearings Spark Plugs Arc lamp tubes Laser hosts Gem stones Alumina powders Abrasives Catalyst pellets Alumina coatings Oxidation protection of aluminum and aluminum alloys Capacitors Transisitors Bioceramics Alumina fibers Thermal insulators Fire retardation Alumina as a component of...

The fimction of technical products can be distinctly improved by innovative material applications. Particularly, high-performance ceramic materials have gained a great potential for application in many fields because of their outstanding properties. Examples are hip joint endoprotheses on alumina or zirconia basis, slide bearing and burner components from silicon carbide, as well as ceramic roller bearing components or the frequently... 

Figure 11 shows conversion to iso-heptanes to be negligible for (0.5 wt. %) platinum supported on activated carbon (Pt/C) as the only catalyst, and also for (0.4 wt. %) platinum on silica-gel (Pt/Si02). No detectable conversion was obtained with silica-alumina. A mechanical mixture of either of the Pt-bearing particles with silica-alumina of about 150 m.Vg-surface area, both in millimeter diameter particle size (1000m), immediately resulted in appreciable isomerization ( SiAl with Pt/C SiAl with Pt/Si02). Isomerization increases rapidly for smaller component particle sizes, of 70/i and S i diameters. It approaches the performance of a silica-alumina that has been directly impregnated with platinum, and which has... 

The Weibull modulus of an alumina bioceramic is given as 8.4. (a) What does a value of m = 8.4 imply (b) For an implant made out of a metal the value of m 100. What implications would this have for lifetime predictions for the metal component compared to the alumina component (c) How does the value of m affect the design of a component for a load-bearing application ... 

Another alternative bearing for the knee, oxidized zirconium (OXINIUM, Smith Nephew) is now widely used (see Chapter 6, Figure 8.24) [69-71]. Unlike monolithic alumina or zirconia femoral components, oxidized zirconium is produced by diffusion of oxygen into a zirconium-niobium alloy, resulting in a hardened ceramic surface. Thus, the fracture risk associated with monolithic ceramics such as alumina and zirconia is thought to be reduced with OXINIUM. However, because to date no clinical factures of ceramic femoral components for TKA have yet been reported in the literature [67], the abUity to compare actual clinical fracture rates among alternative knee bearings is not yet possible. 

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