Electrodeposition and Corrosion Resistance of Ni-Graphene Composite Coatings

The research on the graphene application for the electrodeposition of nickel composite coatings was conducted. The study assessed an important role of graphene in an increased corrosion resistance of these coatings. Watts-type nickel plating bath with low concentration of nickel ions, organic addition agents, and graphene as dispersed particles were used for deposition of the composite coatings nickel-graphene. The results of investigations of composite coatings nickel-graphene deposited from the bath containing 0.33, 0.5, and 1 g/dm³ graphene and one surface-active substance were shown. The contents of particles in coatings, the surface morphology, the cross-sectional structures of the coated samples, and their thickness and the internal stresses were studied. Voltammetric method was used for examination of the corrosion resistance of samples of composite coatings in 0.5 M NaCl. The obtained results suggest that the content of incorporated graphene particles increases with an increasing amount of graphene in plating bath. The application of organic compounds was advantageous because it caused compressive stresses in the deposited coatings. All of the nickel-graphene composite layers had better corrosion resistance than the nickel coating.     

Wear resistance of nanocrystalline composite NI-B coatings

The nanocrystalline composite electrochemical coatings prepared with nickel matrix and boron particles were investigated. Nickel plating bath of low nickel ion concentration (0.76 mol/dm³) with brightening organic compound, surfactants and dispersed boron particles content was used for coatings electrodeposition. Boron particles content was determined gravimetrically. The dependence of boron content in composite Ni-B coatings on the concentration and kind of the organic additives was investigated. The coatings structure was established using TEM. The microhardness of the deposited layers was measured by Vickers' method at the load of 0.01 and 0.05 kg. The wear experiments of Ni-B coatings were made without lubrication using the technique based on measuring system comprising a flat surface and a ball. On the basis of measurements of wear traces diameter, the wear depth was calculated and assumed as a measure of wear resistance. Tribological properties were investigated using the disc-block measuring system. Friction tests were made on Amsler A-135 machine.The obtained results suggest that the organic compounds used in the experiments had a significant effect on the increase of boron content in coating and the development of nanostructure of nickel matrix.     

Bottom–up assessment of potentials and costs of CO2 emission mitigation in the buildings sector: insights into the missing elements

The Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) has calculated and shown that, currently, the buildings sector has the largest potential for low-cost carbon dioxide (CO₂) mitigation in the short to medium term from application of technological options among the sectors examined, based on bottom–up studies. The potential estimates, however, were derived with no regard to indirect costs of CO₂ mitigation, associated benefits, and non-technological options; these factors might change the magnitude of the potential and the costs associated with its implementation. The question emerges how accurate the indicators of the economic potential are according to the current IPCC method and how much they might change if all factors mentioned were taken into account. While research results are presently not sufficient to fully answer this question and quantitative analyses of non-technological options, transaction costs associated with barriers, and non-energy benefits are scarce and fragmented, this paper makes a first attempt to assess the presently available literature in the field. The paper concludes that the ballpark is right for the figures reporting the cost-effective potentials in the buildings sector; however, these assessments indeed need to be corrected by incurred transaction costs and co-benefits relevant for the particular assessment, as well as the potential of non-technological options. The paper also outlines a research agenda in the area so that a possible next Assessment Report of the IPCC can derive a more accurate estimate of the bottom–up potential of CO₂ mitigation.