Environmental effect abrasion

Most data are derived for a single influence and the effect of combining more than one influence has then to be determined, e.g. combining temperature, loading and exposure to abrasive particles to characterize the environmental effects on a pump housing. 

Natural environmental exposure, the exposure of materials or products to natural environmental conditions, can be regarded as a form of simulated service testing. Such exposures provide information on the durability of the material without the effects of such factors as fatigue and abrasion. 

The slurry is the third important key player among the three listed above. Key slurry parameters that affect CMP are discussed in Chapter 3. Slurries provide both the chemical action through the solution chemistry and the mechanical action through the abrasives. High polishing rates, planarity, selectivity, uniformity, post-CMP ease of cleaning including environmental health and safety issues, shelf-life, and dispersion ability are the factors considered to optimize the slurry performance. For hard materials like W and Ta mechanical effects are more important. On the other hand for soft... 

Optical KLenents. Problems which are common to many solar-related optical elements Include dirt retention, cleaning, surface abrasion, and photodegradation. A common feature of some of these problems Is that the deleterious effects occur at an Interface. Ultraviolet radiation, atmospheric components, mechanical stress, etc., can have a profound effect on performance by changing surface characteristics. The lifetimes of UV stabilizers can be limited by exudation permeability can cause harmful reactions at Interfaces and mechanical properties can be Influenced by surface crazing. In other applications mechanical behavior of the bulk polymer Is critical and virtually all applications require that the polymer system withstand multiple environmental stresses simultaneously. 

The common factor to the subjects considered in this chapter is that they arc all concerned with evaluating the resistance of materials to exposure to some environmental agent other than temperature (and air). Durability involves many factors mechanical, thermal, and electrical stresses including creep, fatigue, and abrasion. These can be difficult enough to measure and are greatly complicated by the effects of nonambient temperatures, but when the effects of environments are superimposed, the problems can increase in a quantum leap. 

There are many matrix choices available and different types have different impact on the processing techniques, physical and mechanical properties and environmental resistance of the finished composites. In selecting matrix material, some factors may be taken into consideration like (1) the matrix must be easy to use in the selected fabrication process, (2) the resultant composite should be cost effective, (3) the matrix is be able to withstand service conditions, viz., temperature, humidity, exposure to ultraviolet environment, exposure to chemical atmosphere, abrasion by dust particles, etc. 

Composite Nature of Coatings. The surfaces of many materials exposed to the environment are prone to the effects of abrasion, corrosion, radiation, electrical or magnetic fields, and other conditions. These surfaces must have the ability to withstand these environmental conditions and/or provide certain desirable properties such as reflectivity, semiconductivity, high thermal conductivity, or erosion resistance. 

What effect wdl the environmental conditions have on the deposited coatings and, if subject to abrasion, what wdl be the edge effect of deposited metal on the substrate ... 

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