Physical corrosion

After lapping, the sliders will be cleaned, and then a passivation film of diamond-like carbon (DLC) will be deposited on the surfaces of sliders through chemical vapor deposition (CVD) to protect the pole area from chemical-physical corrosion and electrostatic discharge attack. Corrosion in pole areas will result in loss of read/write functions. A corrosion test was taken to examine the ability of the sliders polished by different slurries as shown in Table 6. It can be seen that the MRR change rate of the sliders polished by UFD slurry is much less than that polished by the slurry T5qre III, that is, the capability of anti-corrosion of the former is much better than that of the latter. 

Physical Corrosivity Explosivlty Extremes of pH Elammablllty Radioactivity Strong oxidizers or reducers... 

Stress corrosion can be subdivided in chemical and physical corrosion ... 

Physical Corrosivity Explosivity Extremes of pH Flammability Strong oxidizers or reducers Radioactivity... 

Physical corrosion is the interaction of a thermoset polymer with its environment so that its properties are altered but no chemical reactions take place. The diffusion of a liquid into the polymer is a typical example. In many cases, physical corrosion is reversible after the liquid is removed, the original properties are restored. 

When a polymer absorbs a liquid or gas, that results in plasticization or swelling of the thermoset network, physical corrosion has taken place. For a cross-linked thermoset, swelling caused by solvent absorption will be at a maximum when the solvent and polymer solubility parameters are exactly matched. 

Physical corrosion is the interaction of a thermosetting polymer with its environment causing an alteration in its properties but with no chemical... 

Furthermore, some of these countermeasures may increase an electrochemical or a physical corrosion of materials. An increase in flow velocity, for example, may increase erosion of constmctional materials, whereas altering the pH may cause corrosion of copper or aluminum alloys. Thus, benefit and potential cost should be evaluated carefully before choosing a certain countermeasure. 

Corrosive poisons—acids, alkalis, which cause physical corrosion of body tissue... 

Composition is normally expressed by a distillation curve, and can be supplemented by compositional analyses such as those for aromatics content. Some physical properties such as density or vapor pressure are often added. The degree of purity is indicated by color or other appropriate test (copper strip corrosion, for example). 

If produced gas contains water vapour it may have to be dried (dehydrated). Water condensation in the process facilities can lead to hydrate formation and may cause corrosion (pipelines are particularly vulnerable) in the presence of carbon dioxide and hydrogen sulphide. Hydrates are formed by physical bonding between water and the lighter components in natural gas. They can plug pipes and process equipment. Charts such as the one below are available to predict when hydrate formation may become a problem. 

Another method by which metals can be protected from corrosion is called alloying. An alloy is a multicomponent solid solution whose physical and chemical properties can be tailored by varying the alloy composition. 

Deteriora.tlon. Apart from physical damage that can result from carelessness, abuse, and vandaUsm, the main problem with metal objects Hes in thek vulnerabihty to corrosion (see Corrosion and corrosion control) (127,128). The degree of corrosion depends on the nature and age of the object. Corrosion can range from a light tarnish, which may be aesthetically disfiguring on a poHshed silver or brass artifact, to total mineralization, a condition not uncommon for archaeological material. 

Physical Properties. An overview of the metallurgy (qv) and soUd-state physics of the rare earths is available (6). The rare earths form aUoys with most metals. They can be present interstitiaUy, in soUd solutions, or as intermetaUic compounds in a second phase. Alloying with other elements can make the rare earths either pyrophoric or corrosion resistant. It is extremely important, when determining physical constants, that the materials are very pure and weU characteri2ed. AU impurity levels in the sample should be known. Some properties of the lanthanides are Usted in Table 3. 

Table 2 Hsts some of the physical, toxicity, flammabiUty, and reactivity properties of common chemicals (10,13,42,45—51). Also given are some of the quantities specified for reporting spills and for compliance with legislated requirements. The OSHA regulations require that material safety data sheets (MSDS) be developed for all process materials, so that the ha2ard data can be communicated to employees (52). Characteristics of toxicity, flammabiUty, chemical iastabiUty, reactivity and reaction energy, operatiag coaditioas, and corrosive properties of constmction materials must all be considered ia analy2iag ha2ard poteatials of chemicals and chemical operations.

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