Silicon carbide paper

Figure 10.9 Voltammetry of 0.2 mM 2,6-diamino-8-purinoI in pH 7.0, 0.5 M phosphate buffer at (A) pyrolytic graphite, resurfaced with 600 grit silicon carbide paper (B) polished GC. Scan rate = 0.2 V/s. [Adapted from Ref. 18.]...

Composite samples are sectioned with a diamond saw and mounted in cold curing epoxy resin. Because of their porous nature, the composites are infiltrated under vacuum and subsequently cured under pressure in order to force the mounting resin into the pores. Mounted samples are ground flat on 240 grit silicon carbide paper, finely ground with a 9 pm oil-based diamond slurry and finally polished with a 1 pm diamond slurry and a 50 nm silica suspension. 

Fig. 5. Estimate of the strain gradient in a brass surface abraded on 600-grade silicon carbide paper.

To examine the effect of the inner layer, the oxidation of "as received" deposit was compared with that of material from which the inner layer had been removed by abrasion on silicon carbide papers,... 

Vigorous abrasion of specimens should be avoided, since hydrogen absorption by the specimen may result. It has been found that abrasion of a mild steel surface by 120 grade silicon carbide paper resulted in... 

Grind the exposed surface with the grinder/pol-isher using No. 320 adhesive-backed, silicon-carbide paper for approximately two to three minutes. 

For example, a crushed coal sample will be formed into a briquette with a cold-setting epoxy resin. When the resin is set, the surface is ground using water-resistant, adhesive-backed silicon carbide papers of grit size numbers 240, 320, 400, and 600. Then, polishing is carried out using aluminum oxide powders of specified sizes followed by treatment with a nap-free cloth of cotton and silk and chemo-textile material backed with water-resistant adhesive. There are, of course, suggested sequences for this procedure to produce a surface suitable for microscopic examination. 

Steel disks (AISI 52100) were polished to a nal surface roughness Ra) below lOnm using silicon carbide paper and diamond paste. The samples were ultrasonically cleaned in ethanol and analyzed for surface contamination by XPS immediately prior to tribotesting. Commercial 4 mm ball-bearings (AISI 52100) were used as a counter-face. 

Running water is generally used as a medium when grinding on diamond disks or silicon carbide papers. The water serves to carry away the swarf and cool the sample. Oils, kerosene, and glycerol-alcohol mixtures are used as media for grinding water-sensitive ceramics. If loose diamond particles are used in place of diamond grinding disks or silicon carbide papers, then oil-soluble pastes or the conventional diamond suspensions based on water, alcohol, or oil are used in connection with suitable lubricants. 

If the polymer is hard, such as a thermosetting resin, one method to consider is gentle abrasion of the surface with silicon carbide paper. This action will transfer a small quantity of the polymer to the abrasive paper,... 

Once the sample is fixtured properly, the surface should be ground smooth and flat. Grinding is traditionally performed using silicon carbide papers, but sometimes diamond impregnated grinding media are used. Grinding can be done manually with stationary abrasive papers, manually... 

Less common situations to consider are when studies of surface contamination are required and when the surface cannot be separated and brought to the instrument. In the first example, a practical solution is to grind a small amount of alkali halide powder (KBr or KCl) at the point of the contamination. This will result in the transfer of some of the contaminant to the alkali halide, and this in turn may be examined either by the compressed pellet technique or by diffuse reflectance. A way to assist this surface extraction is to add a few drops of a solvent, such as methylene chloride, in the area of the contamination. In the second situation, sampling may be performed by gently abrading the surface with silicon carbide paper. This action will transfer a small amount of the surface to the abrasive paper, and this in turn may be examined with the aid of a diffuse reflectance accessory. 

One other technique, previously described, is the abrasion of the surface of the sample with a silicon carbide paper. The abraded material may be collected as a dust and analyzed as a compressed alkali halide pellet or by diffuse reflectance. Alternatively, the spectrum of the sample from the surface of the abrasive paper may be obtained with a diffuse reflectance accessory. 

As-cast AlxCoCrFeNi alloys were prepared according to molar ratios of x = 0, 0.25, 0.50, and 1.00 (called C-0, C-0.25, C-0.50, and C-1.00, respectively) in a vacuum arc remelter. Table 1 lists the composition of the alloys. Test specimens were cut in 0.8 cm x 0.8 cm x 0.3 cm and cold-mounted in epoxy with the outside surface from a surface of 0.8 cm x 0.8 cm of specimens. The specimens were subsequently ground and polished with grit 1000 silicon carbide paper, rinsed and dried in preparation for electrochemical tests and weight loss measurements. During determination of the weight loss, six sets of samples were dipped in... 

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