SURFACE TREATMENT Subject

Laser peening (surface treatment) Subjecting a surface to a series of laser pulses that melt the surface, introduce compressive stresses in the surface, and give a fine-grained structure to the surface region. See also Shot peening. 

When the test is to be made to predict the performance of a material in a particular service, the ideal procedure would be to have the surface of the test-pieces duplicate the surface of the material as it would be used. Here, however, a complication is presented by the fact that materials in service are commonly used in several forms with different conditions of surface. Where the number of materials to be compared is large, it will usually be impractical to test all the conditions of surface treatment of possible interest. The best practical procedure, then, is to choose some condition of surface more or less arbitrarily selected to allow the materials to perform near the upper limits of their ability. If all the materials to be tested are treated in this way, and preferably with uniform surface treatment, the results of the test will indicate the relative abilities of the different materials to resist the test environment when in a satisfactory condition of surface treatment. Then, if it should be considered prudent or desirable to do so, the most promising materials can be subjected to further tests in a variety of surface conditions so that any surface sensitivity can be detected. 

Best approach toward a general solution of all problems of induced stability appears to be a two-pronged surface treatment involving electrostatic and steric protection. In order to increase repulsion energy, zeta should be increased and to enable the particles to resist compression to a distance of separation less than that at E, a bulky molecule should be attached firmly to the surface. Some systems do not accept both steric and ionic protection but for those that do, the combination shows most promise. Er should not be increased without some assurance that the particles will not be subjected to drastic compressive forces. 

Some nonconductors, such as the polymers polycarbonates and polystyrenes, must be subjected to a surface treatment prior to activation to ensure good adhesion of palladium nuclei. Surface treatment can include the use of chemical etchants for plastics or reactive gas plasma treatments (66). 

The method of providing detector elements as disclosed in GB-A-1559473, shown above, is further improved in GB-A-1568958 in which an anodic surface treatment is used to form a passivation layer. This layer is found to have a protective or passivating effect which allows the device to be subjected to elevated temperatures (90°C) without severe degradation in the detectivity of the detector elements. 

To investigate the control factors of welded component s fatigue behaviour, and use the analytical methods for estimating the total fatigue life of welds subjected to variable-amplitude loading histories and surface treatments, in order to find some possible methods to improve the fatigue strength. 

Figure 1 Surface finish versus pitting potential for 316 stainless steel subject to various surface treatments. (From G. E. Coates. Materials Perf., Aug. 1990, p. 61.)...

Sheets of PVC were subjected to argon plasma immersion ion implantation over various exposure times (from 900 to 10,800 s) and the effect of exposure time on the composition, roughness and wettability of the PVC sheets investigated. It was found that the wettability of samples increased with surface treatment and that the hydrophobic character of samples treated for shorter periods recovered either partially or completely. Samples exposed for the longest time remained highly hydrophilic. 21 refs. BRAZIL... 

The principal areas of science and engineering dealing with metals and alloys are chemical metallurgy and physical metallurgy. Subjects of chemical metallurgy are the extraction and refining of metals, liquid metal treatments, corrosion protection, and surface treatment of metals. The study of metals and alloys with respect to their crystal structures, constitution, microstructure, and properties (especially, mechanical) is the subject of physical metallurgy. ... 

On the other hands, it becomes obvious that SOx and NOx in flue gas can be removed at room temperature by using active carbon fibers (ACF) subjected to surface treatment such as heat treatment [1, 2], The flue gas treatment technology using ACF is a semidry oxidation type de-SOx method which is effective even around room temperature. In addition, this technology enables by-products such as sulfuric acid, sulfates, nitric acid, and various nitrates to be recovered, and is applicable in the field of flue gas treatment to which the conventional de-SOx method, such as the limestone gypsum method, could not be applied for economical reasons. 

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