Dry silicon carbides

FIGURE 26.1 Experimental friction data (left) as function log speed at different temperatures and master curve (right) of an acrylate-butadiene rubber (ABR) gum compound on a clean dry silicon carbide 180 track surface referred to room temperature. (From Grosch, K.A., Sliding Friction and Abbrasion of Rubbers, PhD thesis. University of London, London, 1963.)... 

FIGURE 26.8 The friction master curves of the acrylate-hutadiene rubber (ABR) gum mbber on (a) dry glass, (b) dry clean silicon carbide 180, (c) dry silicon carbide dusted with MgO powder, (d) Alumina 180 wetted with distilled water, and (e) wetted with water +5% detergent. 

The oxidation rate of granular silicon carbide in dry oxygen at 900—1600°C was studied and an equation for the effect of particle size was derived (61). 

In the drying of compound intermediates of refractory and reactive metals, particular attention is given to the environment and to the materials so that the compound does not pick up impurities during the process. A good example is the drying of zirconium hydroxide. After the solvent extraction separation from hafnium, which co-occurs with zirconium in the mineral zircon, the zirconium values are precipitated as zirconium hydroxide. The hydroxide is dried first at 250 °C for 12 h in air in stainless steel trays and then at 850 °C on the silicon carbide hearth of a muffle furnace. 

Shear modulus, 13 498, 26 777 of dry foams, 12 16 of silicon carbide, 22 526t of vitreous silica, 22 430 of wet foams, 12 17-18 Shear plane, polymer colloid, 20 383, 384 Shear pulverization, of polymer blends, 20 326... 

A Very practical application of infrared radiation is found in radiant heating. Solid radiators, such as hot tungsten filaments, alloy wires, and silicon carbide rods arc used widely as sources of infrared to provide surface healing by radiation. Commercially available infrared lamps are extensively used in specially designed ovens for drying painted and enameled surfaces. 

Prior to analysis, the FCC catalyst samples were embedded in copper doped thermosetting epoxy to provide increased electrical conductivity. They were dry polished with silicon carbide to approximate cross-sections. 

The silicon carbide-based ceramic layer is obtained by CVD activated by a microwave plasma (2.45 GHz) on the tantalum previously cleaned by an argon plasma (56 min, 133 Pa, 250 W) at a temperature identical to the deposition temperature (T = 570°C), lower than the substrate annealing temperature. After readjustment of the total pressure and microwave power by introduction of a precursor (TMS) in the argon flow, the SiC coating is produced under selected conditions (66 Pa, TMS/Ar = 0.2/5.5 l.h-, T = 570°C, 350 W) derived from a previous parametric study. Coatings obtained then presented low dry friction coefficients. The mechanical properties, which are essential in order to be able to appreciate the mechanical stability, were acquired by several methods ... 

It is technically easier to manufacture a molded component from SiC-powder by slip casting or dry pressing, working it mechanically and then sintering pressureless at 1950 to 2000°C. Due to the low sintering activity of silicon carbides, such processes have only been recently successfully carried out with the advent of fine particulate SiC-powders (specific surface area > 5 m /g) with low oxygen-contents (< 0.2%). Boron or aluminum and free carbon or boron carbide are added as sintering aids. 

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