Разработка техники и технологии для осуществления зарезки боковых стволов в добывающих скважинах Нефтегорского месторождения

Surface alloys were made on mild steel, coated with nicker and chromium using laser surface alloying. Mild steel was coated with a composite layer of nickel and chromium using the plasma technique. This was followed by laser irradiation using a continuous carbon dioxide laser. Oxidation and corrosion behaviour of these alloys was then determined by carrying out oxidation in air at 800 degrees C and corrosion tests at room temperatures in 1 N H2SO4 With a 75 mu m layer of nickel and chromium each, it was possible to make surface alloys on mild steel, which had a chromium concentration of 6-7 wt%, but the nickel concentration varied from 10-20 wt%. Oxidation behaviour improved significantly over the as-coated specimen and aqueous corrosion improved considerably

Effect of water vapour on the oxidation of FeCrAl- and NiCrAl-base ODS alloys

In the present work, oxidation of Fe-base (PM2000) and Ni-bask (MA6000, PM3030) alloys in Ar/(20%)O-2 and Ar/(4%)H-2/(2%)H2O at 1000 degrees C is described. All the alloys showed a reduction in the oxidation rate in Ar/H-2/H2O. However, the alloys which incorporate considerable amount of Ti in the oxide showed very small difference in the oxidation rates. The alloy which incorporate significant amount of Ni in the oxide showed a marked reduction in the oxidation rate in Ar/H-2/H2O These anomalies are explained by assuming that the oxidation mechanism is changed from grain boundary diffusion to volume diffusion in Ar/H-2/H2O and therefore doping effect and proton incorporation controls the later part of oxidation. The insignificant reduction of oxidation rate of MA6000 in wet condition is explained as due to the resultant effect of donor and acceptor doping of Cr2O3 by Ti and Ni. The similar behavior of PM2000 is also due to doping effect of Al2O3 by Ti and Fe. The significant reduction in the oxidation rate of PM3030 in wet condition is due to acceptor doping of Cr2O3 by Ni

Development and characterization of coatings on interconnector (Cr-ODS) used in SOFCs

Oxidation behavior of aluminide coated Cr-ODS alloy having different coating thicknesses was investigated at temperatures ranging from 800-950 degrees C in air. Coating degradation due to rapid Al diffusion into the matrix resulting in Kirkendall porosity was characteristic of all coated alloys. The microhardness of the alloy was substantially increased due to Al diffusion. Pre-oxidation was found to be an effective means of reducing rapid growth of Al coating into the substrate. The aluminide coating modified with Co+Ni showed less tendency towards void formation at the sites where the coating was adhered. Silicide coating did not show any enhancement in the microhardness of the alloy or Kirkendall porosity as a result of Si diffusion. From this study, it has been found that an effective silicide coating for Cr-ODS alloy can be produced by selecting suitable coating parameters