Composite coating oxidation kinetics

Oxidation kinetics (a) and oxide scale spallation (b) of 1Cr13 alloy coated withYPSZ-AljOj composite coatings at 900°C in air. 

Polymerization of 4-vinylpyridine has also been performed, resulting in a non-electroactive and non-conducting coating . The kinetics of charge transport has been measured when this polymer contains electrostatically trapped Fe(CN)6 ", IrCls " or tris(2,2 -bipyridine)osmium- 111/11) complexes 3 . Incorporating IrCle , the electrode is able to catalyze the oxidation of iron(II) . A composite electrode coated with a mixture of cellulose acetate and poly(vinylpyridine) has been described . This mixture allows the binding of counterionic reactants in acidic media, while maintaining the size exclusion discriminative properties of cellulose acetate. 

Abstract. Destructive adsorption of halocarbons on nanocrystalline oxides has been studied. The effect of nanoparticle size and phase composition on the reaction kinetics is discussed. The reactivity of nanocrystalline oxides has been found to increase after deposition of a permeable carbon coating. The possibility of synthesis of new nanocrystalline halogenated materials using nanoscale oxides as precursors has been demonstrated. 

In recent years, there has been a growing interest in the electrochemical synthesis of composite materials consisting of metal matrix with embedded particles of oxides, carbides, borides, etc. Metal-matrix composites offer new possibilities in fabrication of ftmctional coatings with radically improved durability and performance [1], However, in spite of the efforts of many researches, the overall picture of the processes occurring during co-deposition of metal with dispersed phase and mechanism of particle-induced modification of mechanical and chemical properties still remain unclear. In this study, we focused on the kinetics and mechanism of the electrochemical co-deposition of nickel with highly dispersed oxide phases of different nature and morphology. 

Example 13-5 Using the one-dimensional method, compute curves for temperature and conversion vs catalyst-bed depth for comparison with the experimental data shown in Figs. 13-10 and 13-14 for the oxidation of sulfur dioxide. The reactor consisted of a cylindrical tube, 2.06 in. ID. The superficial gas mass velocity was 350 lb/(hr)(ft ), and its inlet composition was 6.5 mole % SO2 and 93.5 mole % dry air. The catalyst was prepared from -in. cylindrical pellets of alumina and contained a surface coating of platinum (0.2 wt % of the pellet). The measured global rates in this case were not fitted to a kinetic equation, but are shown as a function of temperature and conversion in Table 13-4 and Fig. 13-13. Since a fixed inlet gas composition was used, independent variations of the partial pressures of oxygen, sulfur dioxide, and sulfur trioxide were not possible. Instead these pressures are all related to one variable, the extent of conversion. Hence the rate data shown in Table 13-4 as a function of conversion are sufficient for the calculations. The total pressure was essentially constant at 790 mm Hg. The heat of reaction was nearly constant over a considerable temperature range and was equal to — 22,700 cal/g mole of sulfur dioxide reacted. The gas mixture was predominantly air, so that its specific heat may be taken equal to that of air. The bulk density of the catalyst as packed in the reactor was 64 Ib/ft. ... 

P. N. Bartlett, E. N. K. Wallace, The oxidation of beta-nicotinamide adenine dinucleotide (NADH) at poly(aniline)-coated electrodes Part II. Kinetics of reaction at poly(aniline)-poly(styrenesulfonate) composites, Journal of Electroanalytical Chemistry 2000, 486, 23. 

Ail of the kinetic tests were conducted by using the same batch of tubing obtained from an operational northeastern U.S. drum boiler. The tubes were machined to a constant OD (3.34 cm) and length (4.74 cm) with a total surface area of 102.8 cm. The interior surfaces were coated with about 1 g of oxide and 50 mg of Cu. The composition of the scale as determined by x-ray diffraction and the chemical composition of the boiler tube are shown in Table 2. In each of the dissolution tests, two AISI 1010 carbon steel coupons in a PTFE mount were added to give a total wetted surface area of 190 cm. The chelating agents tested were obtained from commercial sources and were used without further purification. The chelants and their iron formation constants are described in Table 3. 

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