Bearings materials for

In addition to the use of softer bearing materials for applications where abrasives may potentially be present, it is important to properly maintain filters and breathers, which should regularly be examined. In order to avoid oil supply contamination, foreign material that collects at the bottom of the bearing sump should be removed on a regular basis. 

Iron ores occur in igneous, mctamorphic or sedimentary rocks, or as weathering products of various primary iron-bearing materials- For convenience of analysis, iron ores are grouped into (I) igneous tires. 121 contact ores. i3i hydrothermal ores. (4) sedimentary ores, with several suhclassihcaiions of the latter ores. Brief definitions follow ... 

Finally, with regard to laboratory testing all the important service conditions must be incorporated if the results are to be of value to the designer. For example the effect of abrasives has already been mentioned, but in aircraft applications the leakage of fuel or other fluids onto polymer bearings can be a major factor in their performance. In the nuclear industry candidate bearing materials for exposed applications must have been tested under suitably irradiated conditions. 

Cast iron is not used as a bearing material for rotating parts it has high load characteristics and is used mainly for sliding surfaces such as machine-tool parts, e.g. milling-machine slides, lathe beds, etc. 

For which properties did Chamley choose UHMWPE over other polymers as a bearing material for total hip replacements ... 

D. W. Wisander and R. L. Johnson, Wear and Friction of Possible Seal and Bearing Materials for Liquid Hydrogen, NASA TN (in process) (1960). 

New Polymers and Other Modes of Deformation.—Three relatively new polymers have become available recently poly (ether ketones), poly (ether ether ketones) and poly(ether sulphones). Poly(ether ether ketones), (PEEK), have good electrical insulating properties and very good abrasion resistance. This combination makes the polymer an attractive coating for electrical conductors. The same polymer is also attractive as a load bearing material for moving parts. Poly(phenylene sulphide) continues to be developed for this purpose but the PEEKS are much simpler to fabricate. Linear low-density polyethylenes are expected to be widely available in the near future. These materials have many attractive features, particularly as packaging materials. 

This latest trend in load-bearing materials for arthroplastic applications involves the development of highly fracture-resistant alumina/zirconia composites, as an alternative choice to alumina and zirconia monolithic ceramics. Composite materials are designed from both chemical and microstructural viewpoints in order to prevent environmental degradation and fracture events in vivo. Based on the experimental determination of an activation energy value for an environmentally driven tetragonal to monoclinic transformation, the long-term in vivo environmental resistance of prostheses made from these composite materials can be predicted (Chevalier et al., 2009). 

The metal also finds appHcations in other alloys. Cable sheaths are made of lead that contains antimony, and lead shot for ammunition is not made of pure lead but of lead alloyed with 1-8% antimony. The American Isaac Babbitt (1798-1862) invented the bearing alloy named babbitt metal. It is an alloy of copper, antimony and tin, characterized by good antifriction properties, and used as the bearing material for axles and crankshafts. Britannia metal is another tin alloy with about 2% copper and 5-10% antimony. It is a silvery white alloy of tin, similar in appearance to pewter but harder. It is used for the manufacture of tableware. 

Ainsworth R, Fading G, Bardos D. An improved bearing material for joint replacement prostheses carbon fiber-reinforced UHMW polyethylene. Trans 3rd Soc Biomater 1977 3 119. 

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