Wear surface, visual observation

The visual observation of the polymer wear surface is the simplest method for characterizing the wear process. Frequently a considerable amount of very useful information can be gained from the use of the light optical and scanning electron microscope studies of the polymer surface that has undergone wear. 

An example of how visual observation can assist in wear studies has been demonstrated in the erosion behavior of thermoplastics ( ). In the erosion of polymers the shape of the impinging particle on the polymer surface determines the mechanism by which wear occurs. 

A host of analytical tools are available to the tribologist for the study of the wear of polymers and polymer films. Much can be learned about the wear behavior of polymer with visual observation of the wear surfaces with the scanning electron microscope while surface profilometer can assist in quantifying polymer wear. 

A visual examination should be made to yield information on the general condition of the part, component or surface to be examined, including such conditions as the presence of scratches, wear, cracks, corrosion or erosion on the surface, or evidence of leaking. Optical aids such as television cameras, binoculars and mirrors may be used. Surface rephcation as a method of visual examination may be considered acceptable, provided that the resolution at the surface is at least equivalent to that obtainable by visual observation. Any visual examination that requires a clean surface or decontamination for the proper interpretation of results should be preceded by appropriate cleaning processes. 

As defined in Section 13.1 the wear of a solid body is the consequence of loading and motion at the contacting interface of two surfaces. In the present section we propose to inquire into the nature of the basic mechanistic phenomena that can take place at the interface in such circumstances. The occurrence of certain processes is easily visualized adhesion at the interface, rupture of adhesions, displacement of material by plowing or shearing, detachment of displaced material, fatigue and cracking, oxidation, etc. and in fact all of these processes have been observed and identified, either singly or in combination, in cases of wear as it actually occurs. 

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