Surface contamination tests

Surface contamination test Packaging and storage For removable and fixed alpha... 

When required, perform adhesion tests, curing tests or tests for surface contamination. 

With materials like the stainless steels, which may be either active or passive in a test environment, it is common practice to produce a particular initial level of passivity or activity by some special chemical treatment prior to exposure. With stainless steels this objective may be subsidiary to eliminating surface contamination, such as iron from processing tools, by treatment in a nitric acid solution which might also be expected to achieve substantial passivity incidental to the cleaning action (ASTM A380 1988). 

The arc resistance of a polymer is the length of time for which we can apply an electrical discharge to its surface before it breaks down and begins to conduct electricity. Breakdotvn typically takes the form of conductive carbonaceous tracks that are caused by oxidation due to locally high temperatures. Polymers -with lowpolarity typically fare better in this test than polar polymers. Arc resistance is reduced by dirt, moisture, and other surface contaminants. 

For T3250 processed wafers, ESCA shows an increase in Si and oxygen surface concentrations with a concurrent loss in carbon concentration. Therefore, carbon surface contamination on the gold is being replaced with -the chemisorbed or physisorbed primer species. HMDS-treated Au surfaces exhibited no such change in surface chemical nature, consistent with the no improvement adhesion lifting test results for that promoter. 

Chavalnitikul, C. and L. Levin (1984). A laboratory evaluation of wipe testing based on lead oxide surface contamination. Am. Ind. Hyg. Assoc. J., 45, 311-317. 

Similar logical tests can be applied to increases in surface contamination levels, which may be due to increases in source intensity, or decreases in the efficiency of barrier controls or cleaning and sanitizing procedures. Flow charts illustrating the logical evaluation of data, and investigation of out-of-limit results are useful as starting points in the development of corrective action plans. ... 

There can be little doubt that some alteration of the donee has occurred, but its precise description is elusive. One must note that the test reaction times are all very long, thus increasing the possibilities of surface contamination. All authors agree that much work remains to be done. 

There have been relatively few experimental tests of the Frenkel Kontorova model because of the difficulty in making sufficiently flat surfaces and of removing chemical contamination from surfaces. In one of the earliest experiments, Hirano et al. [126] examined the orientational dependence of the friction between atomically flat mica surfaces. They found as much as an order of magnitude decrease in fi iction when the mica was rotated to become incommensurate. Although this experiment was done in vacuum, the residual friction in the incommensurate case may have been due to surface contamination. When the surfaces were contaminated by exposure to air, there was no significant variation in friction with the orientation of the surfaces. 

Different surfaces (floor, roof, walls) were selected to perform the assays. On those surfaces the reagent, liquid at room temperature (95% of Nixolen and 5% of sodium alkoxide), was spread at room temperature to produce a liquid film such a film at the same time avoided the transfer of the contaminant to the environment. After about 90 hours of action at room temperature, the liquid film was then removed. Samples were taken either on the surfaces (wipe tests, before and after the treatment were made) and on the removed reagent. 

In contrast, surface sodium was only and significantly detected on the two samples for which the NaOH base was used. Thus, the method using Au(CH3COO)3 and urea (hereafter named the ureacetate method) leads to highly-loaded samples with well-dispersed gold particles, no Cl and no Na surface contaminants. The catalytic performances of the Au/Ti02 catalysts were evaluated in the total combustion of methane. Au/Ti02 samples exhibited very poor activity in this test reaction. 

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