Surface deterioration microscopic

Physical deterioration includes compaction by creeping and surface deteriorations by scratching and vibration. Creeping is accelerated at higher temperatures and pressures, resulting in the membrane compaction. This phenomenon is well analyzed and the membrane characteristics of compaction can be estimated in terms of m-value. Scratching and vibration can develop the microscopic defects in the surface structure of membranes, and give poor performances. We discussed this type of deterioration in Mexico in 1976 ( ). 

Replication avoids the problem of sample deterioration in the instrument, but it is destructive in that reaction of the material cannot be continued after the replica has been prepared. Transitory features cannot be detected unless a series of preparations are examined corresponding to increasing progress of the reaction considered. The textures of replicas have been shown [220] to be in satisfactory agreement with those of the original surface as viewed in the scanning electron microscope. The uses and interpretations of observations made through sample replication procedures are illustrated in the studies of decomposition of metal carboxyl-ates by Brown and co-workers [97,221—223]. 

Figure 6. Scanning electron microscopic view of membrane surfaces that were biologically deteriorated. Colonies of the microorganism on the surface were removed.

Examination using a scanning electron microscope (SEM) of the surface of abraded polyurethane shows cutting and gouging marks on the surface. The surface can deteriorate further, and fatigue cracks can start to appear. If the conditions are extreme, the surface can soften drastically and molten/ decomposed polyurethane can be seen under the SEM. 

TA Thermal analysis Thermal energy Heat dissipation Microscopic surface structure Adsorption energy, lubricant deterioration, etc. Transition cell structure, reaction products, etc. 

The optical microscope is the primary analytical technique of conservators and archaeologists to investigate surface topography, and to assess deterioration products of ceramic and metallic specimens. Although not a sophisticated analytical technique. 

Other variations within the metal surface on a microscopic level influence the corrosion process. Microstructural differences, such as secondary phases or grain orientation, will affect the way corrosion manifests itself. For corrosive environments where grain boimdaries are attacked, the grain size of the material plays a significant role in how rapidly the material s properties can deteriorate. Chemistry variations in the matrix of weld deposits are also factors. 

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