Bearings, ceramic applications

Klawitter, J.J. and Hulbert, S.F. (1971) Application of porous ceramics for the attachment of load bearing orthopedic applications, J. Biomed. Mater. Res. 2, 161. Determined that a minimum pore size of 100(i,m is necessary for bone ingrowth. 

Spinel and AlON transparent ceramics have been evaluated in terms of in vitro cytotoxicity, cell-materials interactions, and tribological performance, for potential wear resistant load bearing implant applications [179]. These transparent ceramics with high hardness in the range of 1334-1543 HV showed in vitro wear rate in the... 

Another noteworthy effort at nanocomposite fabrication applied ceramic nanoparticles to a ceramic material to enhance osteoconductivity and mechanical performance. Nawa et al. [49] developed a ceria-stabiHzed tetragonal zirconia polycrystal (Ce-TZP) ceramic and incorporated alumina (AI2O3) nanocrystals into it via wet chemistry methods for load-bearing bone applications. Further studies of this material investigated its ability to induce apatite formation [50], in vivo biocompatibility, and resistance to wear [10] with favorable results. 

In this particular example as in many others, a proper analysis of cost is a crucial factor. An example is the production of balls for ball bearings. Coated ball bearings (or monolithic silicon nitride) greatly outperform steel balls but their cost is considerably higher. Steel balls in passenger-automobile applications are satisfactory and normally last the life of the car and the far-longer life of the ceramic balls is not needed. 

Applications. CVD ceramic powders such as SiC and Si3N4 are used to produce ceramic bodies for a wide variety of applications, either experimentally or in production. These include structural applications in high temperature or corrosive environments where metals are not suitable, in such areas as reciprocating engines, gas turbines, turbochargers, bearings, machinery, and process equipment. 

Raigon-Pichardo, M., Garcia-Ramos, G. Sanches-Soto, P. J. 1996. Characterisation of a waste washing solid product of mining granitic tin-bearing sands and its application as ceramic raw material. Resources, Conservation and Recycling, 17, 109-124. 

Calcium and Phosphate Salts Bloactive Glass Granules Bloactive Glass-Ceramic Granules Orthopedic Load-Bearing Applications... 

Despite this past downward trend, which has persisted in the United States since 1979 with modernization oflarge suppliers in Japan and Europe, growth of 2 to 2.5% is now expected into the mid-1990s. This reflects increased demand for some military applications and commercial aircraft, plus growing needs for farm and construction machinery (2). U.S. production of the relatively new ceramic ball bearings is expected to increase distinctively by about 50% yearly to reach 17 million in 1993 (3). 

Polyurethanes find applications in a wide range of industries in competition with other plastics, ceramics, and metals. Cast polyurethanes are tough, abrasion resistant, have load bearing properties, and are chemical resistant. That makes them the first-choice materials in certain situations. The ability to be easily prototyped and have short production runs is a major positive factor for polyurethanes. 

The first use of ceramics in the electrical industry took advantage of their stability when exposed to extremes of weather and to their high electrical resistivity, a feature of many siliceous materials. The methods developed over several millennia for domestic pottery were refined for the production of the insulating bodies needed to carry and isolate electrical conductors in applications ranging from power lines to the cores bearing wire-wound resistors and electrical fire elements. 

We have a specific interest in the self-assembled structures formed by poly(ferrocenylsilane) block copolymers, such as poly(ferrocenyldimethylsilane-Z -dimethyl-siloxane) (PFS-PDMS) and (ferrocenyldimethylsilane-Z>-isoprene) (PFS-PI). The PFS block contains an iron atom in the main chain repeat unit. These polymers are particularly promising for novel applications, since they can be used as charge-transport materials and, by pyrolysis, as precursors to ferromagnetic ceramics [4-6], Moreover, they can by synthesized with a very narrow molar mass distribution, with excellent control over chain length and composition [7], An important feature of PFS is that the polymers bearing two methyl groups on the silane unit are crystalline, whereas polymers with two different substituents on each silane (methyl, ethyl methyl, phenyl) are atactic and remain amorphous. This feature of the polymer composition has a strong influence on the type of self assembled structures that these poly-... 

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