Electropolished surfaces

Electropolishing surface finishing of a metal by making it the anode in an appropriate solution, whereby a bright and level surface showing specular reflectivity is obtained. 

Fig. 1.18. Secondary electron image of the Ni-Bi transition zone after the second anneal in the as-received condition.150 Temperature 250°C. The time of the first anneal is 14400 s (4 h), while that of the second is 12600 s (3.5 h), 27000 s or 7.5 h in total. Microhardness indentations were put onto the electropolished surface of the cross-section after the first anneal at a load of 0.196 N (20 g). 

Three slices of single-crystal nickel, 10 mm. in diameter and 2 mm. in thickness, respectively, parallel to the (110), (100), and (111) planes were prepared by S. Kaya and denoted, respectively, a, b, and c. They were studied by Matsuda (unpublished) about ten years ago with particular reference to the rates of recombination of hydrogen atoms and to the activation energies for the chemisorption of hydrogen. The latter had been theoretically estimated by Horiuti et ah, as mentioned elsewhere, as functions of the different arrangement of the nickel atoms on the three main crystal planes mentioned above. The relative rates of recombination on the electropolished surfaces of these specimens observed by Matsuda at room temperature followed the qualitative rule ... 

The substrate atomic structure of all of these systems shows an isotropic, cubic symmetry. Therefore, SAM E can not be applied here. Owing to the texture independence of oxide growth, already indicated by the homogeneous interference colors on electropolished surfaces (no grain to grain variations), application of SAME would make no sense anyway. Only a potential crystallization of the oxides that are predominantly optical anisotropic could possibly be detected. However, no indication of any crystallization under the experimental conditions used here was found. Therefore, no SAME measurements are presented in this section. 

FIGURE 5 Contour plot of electropolishing surface roughness RMS (A) for n-type P-SiC at 2.0 Vsce [12]. 

Mechanical preparation techniques such as grinding can introduce significant cold work into the surface layers e.g. the pitting resistance of ground austenitic [3] and ferritic stainless steel surfaces [4] has been shown to be inferior to that of electropolished surfaces. This was attributed to the presence of cold worked surface layers from grinding, although chemical or electrochemical surface treatments can preferentially remove less resistant phases, e.g.inclusions, which would otherwise be responsible for an inferior corrosion performance. ... 

Electropolish Surface de-plating to expose virgin material. Another postmanufacturing technique is electro-polishing, where the entire component is placed in a de-plating bath and a surface layer of metal removed... 

Storage in oil which is frequently used for alkali and alkaline earth metals is not recommended for the rare earth metals. A dry inert atmosphere is much better. The surface of the light lanthanide metals, Ce, Pr and Nd, also can be passivated by the methanol-perchloric acid electropolish described in section 3.3. The electropolished surface remains shiny from 1 to 3 days, depending on the perfection of the surface achieved. 

We are now in a position to calculate the ideal surface resistances to be expected for tin at any temperature and frequency. There are fewer data available for other metals but literature references contain some data on indium, aluminum, lead and mercury. Using the surface resistances calculated from (13) we can calculate the Q s to be expected if there are no extraneous losses in the cavity. In practice there always are extraneous losses. These may be due to dielectric supports, cold working of the metal surfaces or impurity content. The lowest residual resistances are obtained in careful experiments where the metal is an unstrained pure single crystal with an electropolished surface Under these conditions the residual effects may be of the order of 0.1 ), and are attributable to dissipative effects in the dielectric supports used to hold the single crystal. On the other hand, if the metal is severely cold-worked the residual effects may be of the order of 10. ... 

Fig. 3.1-147 Thickness of oxide layer and crack length per area versus testing time. Mo 4N5 Mo ribbon, electropolished surface MY Mo-0.47wt%Y2O3-0.08wt%Ce203 ribbon, electropolished surface, test conditions 5(X)°C/air [1.133]...

The absolute value of and Rq depends on the interval length considered for the measurement. This is illustrated by Figure 3.41 for titanium surfaces polished either mechanically or electrochemically [14]. At small interval length the Rq for the electropolished surface is smaller than for the mechanically polished surface, reflecting the absence of polishing scratches. At an interval length exceeding 300 micrometer... 

Discontinuous metal films produce thin silicon nanowires, which can be mesoporous or sohd (Peng et al. 2006b). They are also employed to form porous silicon or electropolished surfaces (Peng and Zhu 2004). 

UPD lead deposition peak at -0.36 V and a Pb stripping peak at -0.32V. The similarity of the Cu(lll), especially in terms of the peak potentials, obtained with both chemically (Fig. lb) and UHV (Fig. la) prepar suifaces confirmed that the electropolished surface is comparable with the UHV prepared surface. The slight difference in the peak width of the UPD peaks exhibited in this figure may be rationalized by a reduced terrace size 8). 

A disadvantage is the potential of the coimection working loose dueto vibration. The damage to the electropolished surface was already mentioned. Because of the usually unavoidable rough tubing end siuface, particles are a... 

A number of techniques for improvement of surface finish are being studied, including electropolishing, mechanical polishing, pre-oxidation and application of surface coatings. Experiments have confirmed that electropolished surfaces show radioactivity uptake a factor of four to five lower than on mechanical ground or machined surfaces. 

Electropohshing decreases the surface area available for adsorphon and reduces the contamination retention of the surface. The electropolished surface generally exhibits a lower coefficient of friction than a mechanically polished surface. The various surface treatments can alter the outgassing properties of the stainless steel surface. The chemical composihon of and defect distribution in electropolished surfaces can be specihed for crihcal applicahons. This includes the chromium-to-iron raho with depth in the oxide layer (AES), the metallic and oxide states (XPS), surface roughness (AFM), and surface defects (SEM). 

The surface of stainless steel may be passivated by heahng in air. However, the temperature and dew point are very important. A smooth oxide film is formed on 316L stainless steel at 450 C and a dew point of =0°C, but small nodules and surface coarsening result when the oxidahon is done above 550°C in air with this dew point.t These nodules can produce particulate contaminahon in gas distribuhon systems and the coarse oxide adsorbs water vapor more easily than does the smooth, dense oxide. If the dew point of the air is lowered to — 100°C, a smooth oxide with no nodules is formed at higher temperatures. For example, a four-hour oxidation of electropolished staiidess steel at 550°C and a dew point of 100°C produces a 100-300 A-thick oxide compared to the 10-20 A-thick natural oxide found on the electropolished surface with no passivation treatment. Types 304 and 316 stainless steels are more easily passivated than are the 400 series (hardenable) stainless steels. The stainless steel surface can be chemically passivated using organosdanes, which form a hydrophobic surface... 

Polishing, electropolish (surface modification) Polishing a surface that is the anode of an electrolysis cell using a suitable electrolyte. Example Electropolishing stainless steel in a phosphoric acid-based electrolyte. 

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