Carbonation resistance

Boron Carbide. Boron carbide [12069-32-87, B4C, is produced by the reaction of boron oxide and coke in an electric arc furnace (70% B4C) or by that of carbon and boric anhydride in a carbon resistance furnace (80% B4C) (see Boron compounds, refractory BORON compounds). It is primarily used as a loose abrasive for grinding and lapping hard metals, gems, and optics (18).. Although B4C is oxidation-prone, the slow speed of lapping does not generate enough heat to oxidize the abrasive. 

SNR L/CVD Carbon Resist System. We have proposed another approach to improve the nanometer-scale resolution of the SNR 2-layer resist system, viz., the application of carbon films as the bottom layer material. (5) Carbon films prepard by plasma CVD are hard and thermally stable. Figure 5 shows about 40 nm-wide SNR/carbon patterns with a 150 nm pitch on a Si substrate. The narrow lines are well resolved with a steep profile, and the lines at both edges of the pattern have not bent or fallen down. This excellent stability of nanometer-scale carbon patterns facilitates the evaluation of the resolution limit SNR in 2-layer resist application. 

Pure epoxy resins, so-called basic resins, are unsuited to building applications because of their high viscosity. Modifications are necessary to achieve the required viscosity, wettability, carbonate resistance, curing rate, cost reduction and numerous other properties. However, the modifiers must be chosen so as not to impair the other valuable attributes of the epoxy resins. For example volatile solvents are unsuitable for thick coatings, because any solvent retained in the cured system will reduce the mechanical and thermal properties and the corrosion resistance. The specific property needs for a particular application may be tailored to each system to maximise the remarkable potential of epoxy resins (Dow Chemical Company, undated c). 

Fig. 22.—Cyanainide Furnaces at Odda, showing Carbon Resistances (Nitrogen Products Co.),... 

Barber, R. T. (1968). Dissolved organic carbon resists microbial oxidation. Nature 220, 274-275. 

The addition of Cu or Ni into ceria has different effect on the sulfur selectivity of the catalyst under fuel-rich conditions. Cu promotes the complete oxidation and it is selective for Sj. Conversely, on Ni/ceria catalysts, side reactions favor HjS production over elemental sulfur. It is worth to note that both the catalysts suppress carbon formation. The high carbon resistance shown by the metal/ceria based catalysts may be attributed to a higher dispersion of metals into this kind of matrices. Moreover, the high mobility of oxygen ions in ceria allows a rapid supply of oxygen to the metal interfaces speeding up the surface oxidation of carbon species and thus inhibiting deposition of carbon on the catalyst surfaces [25,26]. 

Production of ZrCl4. Zirconium oxide from the hafnium-separation step was mixed with carbon black, dextrin, and water in proportions 142 Zr02, 142 C, 8 dextrin, and 8 water. The mixture was pressed into small briquettes (3.8 X 2.5 X 1.9 cm) and dried at 120°C in a tray drier. The oxide briquettes were charged to the reaction zone of a vertical-shaft chlorinator lined with silica brick. The charge was first heated by carbon resistance strips until it became conductive. During production, the bed temperature was maintained at 600 to 800 C by an electric current passed directly through the bed. After steady conditions were reached, a reactor 66 cm in diameter produced about 25 kg ZrCLt/h. The ZrCU was condensed from the reaction products in two cyclone-shaped aftercondensers in series, and the chlorine off-gas was removed in a water scrubbing tower. 

Narang and S.T. Attarwala, Chemical amplihcation in t diol poly carbonate resists, ACS Polym. Prepr. 26(2), 323 (1985). 

Tests described above show that polymer-modified cementitious coatings may have good initial carbonation resistance, which may be lost due to weathering [7] and good chloride-penetration resistance [8], but no effect on chloride-induced corrosion rate [13]. 

Ohama, Y., and Demura, K., Carbonation Resistance of Polymer-Modified Mortars, Transactions of the Japan Concrete Institute, 9 195-202(1987)... 

A soln. of methyl N-benzyloxycarbonyl- L-phenylalanyl-O-ethoxycarbonyl-L-tyrosi-nate in dioxane stirred 2 hrs. at room temp, with N NaOH -> N-benzyloxy car bony 1-L-phenylalanyl-L-tyrosine. Y 90%. - The alkyl carbonates resist acid cleavage and hydrogenolysis. Also with NHg or hydrazine, and prepn. of other alkyl carbonates, s. R. Geiger et al., B. 101, 2189 (1968). 

The most commonly used type of resistor is the fixed resistor the opposition to the flow of electrons provided by the resistor is fixed and cannot be adjusted. These fixed resistors are typicality made of carbon (Figure 15-9). The carbon resists the flow of electrons and converts the electrical energy... 

Iwa] Method of quenching the melt in ice water after heating at different temperature over liquidus and investigation of stracture under light microscopy. Tammann carbon resistance furnace, electrolytic Fe and Cu, master alloy with 4.25 mass% C and graphite powder. Isothermal equilibria of two Uquids at 1450 and 1540°C in Fe comer at 0 to 4 mass% C and 0 to 30 mass% Cu... 

A small-scale process has been described by Scaife and Wylie in which thorium carbide is used as the feed material. This is made by pelletting a mixture of finely divided thorium oxide with graphite and heating in a carbon resistance tube furnace above 2000°C, in an argon atmosphere. The rather pyrophoric carbide is then reacted with iodine at 500 C and 4 to 200 mm pressure, and sublimed under vacuum to give a yellow thorium tetra-iodide. This is then thermally decomposed on a tungsten filament at high temperature in the normal manner. 

In order to obtain actual performance data a carbon resistance heater was mounted in the sample chamber instead of the microwave cavity and the pressure in the evaporator was monitored with a McLeod gauge. The heat input at any given evaporator pressure is then the total available refrigeration. This is shown in Fig. 8. A carbon resistance thermometer was simultaneously calibrated in the evaporator. The ultimate temperature attained was 0.46°K. 

The direct determination of the shock wave pressure in solids is based on registering the effects of dynamic action of the pressure on a specific property of some materials that are used as an active element in pressure gauges. Such gauges are, for example, the manganin pressure gauge and the carbon-resistant pressure gauge. 

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