Papers by Keyword: Coat

Abstract: The practicability of introducing a synthesized graphite compound, intercalated with oxygen, into the protection coat is grounded. The composition and the method of manufacturing a protection coat based on the oxidized graphite, which does not require preliminary preparation of the metal structures surface before welding with an open arc, have been developed. The effect of the oxidized graphite content in the composition of the protection coat on its thermal stability and thermal expansion coefficient is analyzed. The main technological characteristics of the developed protection coat have been investigated and their compliance with the basic criteria for constructing protection coats has been confirmed.

Abstract: The anti-plane displacement discontinuity method is applied to establish the Fredholm integral equation of the first kind for the orthotropic Functionally Graded Material (FGM) coatings subjected to static shear load. The Young's modulus is assumed to vary exponentially through the thickness while the Poisson's ratio is constant. The fundamental solution of anti-plane displacement discontinuity are derived for orthotropic FGM coating with isotropic substrate. The stress intensity factors are obtained directly from the coefficients of the Chebyshev polynomials.

Abstract: Metal material corrosion resistance chloride ion always is a common problem. In order to further study corrosivity of metal materials in chloride solution, in this paper, a double-layers coating consisted of Ni/Cr-Fe alloy which were prepared by plasma sprayed. The morphology and corrosion resistance of that coating in 3.5 % (wt) NaCl solution were investigated by SEM and Scanning Electrochemical Microscopy (SECM). Because coating had some cracks and pores so the coating sample was corroded and the corrosion current increased rapidly in initial stage. After 10 h of immersion, the corrosion current remained stably. Hence, the sample with plasma spraying Ni/Cr-Fe alloy coating had poor chloride corrosion resistance.

Abstract: Al (OH)₃ coated CaF₂ composite powder was prepared by coating Al (OH)₃ on surface of micro-sized CaF₂ particles using heterogeneous nucleation method. Influence of Al³⁺ concentration, PH value and reaction temperature was studied. The result reveals that CaF₂ particle was uniformly coated with a layer of Al (OH)₃ and Al³⁺ concentration, pH value and reaction temperature are the main factors that affect coating result. Optimum technological conditions are Al³⁺ concentration of solution before reaction at 0.15 mol/L, pH value at 7.5 and temperature at 75 oC.

Abstract: Synthesis method of modified TiO₂ coated on modified serpentine was studied. Synthesized compound material was characterized by SEM, EPMA, and XRD etc. Photocatalytic activities of the obtained samples were examined by degrading tests of simulation phenol wastewater and CN-wastewater. Analysis and test results showes that crystal of TiO₂/ modified serpentine is anatase, material has good photocatalytic activity and regeneration performance. Also, TiO_2/modified serpentine photocatalyst has a very good recycling performance. After ten times recycling the photocatalytic degradation rate has been maintained at more than 99%.

Abstract: Nanometer nickel hydroxide particles coated by cobalt oxy-hydroxide are prepared through chemical precipitation method. The properties of coated Ni(OH)2 particles is characterized by using X-ray diffraction, scanning electron microscopy, constant current charge/discharge test and cyclic voltammetry. Studies are focused on the effects of different amounts of cobalt oxy-hydroxide on structure and electrochemical characteristics of nickel hydroxide. The results show that a structure of β-Ni(OH)2 is preserved and 2.5 wt % CoOOH can form a well distributed conductive network on the surface of nickel hydroxide particles, thereby leading to higher utilization of active material; Compared to other electrodes, the electrodes with 2.5 wt % coated CoOOH show higher specific capacity and better cycling durability, and the electrodes also has better reversibility of the Ni(OH)2/NiOOH redox couple, and higher oxygen evolution potential.

Abstract: Based on the transmission line theory, influence factors of microwave absorbing ability for slab coat were analyzed and calculated. It was found that the parameter absorption rate could not effectively describe the different influence from material character, geometry dimension and microwave. As a solution, the matching property and absorption property needed to be discussed simultaneously. According to the new representation, matching property of coat depends only on the material character, whereas the absorbing ability resulted from the interaction between different interfaces within the sample. The influence of microwave frequency is reflected by interfere between different interfaces. Relatively, in the new representation, the influence from different factors was clear and intuition, which means the applicability of the new representation.

Abstract: The article deals with the influence of the laser melting process on the surface roughness characteristics of the coat deposited on material by electrospark way granted by KEGA 035TUKE-4/2011 project of Ministry of education of Slovak republic. The aim of the article is research of material properties after coating by WC-Co and laser treatment. As the research method were used experiments and tools of statistics. Experiments were carried out on WC-Co coat (the anode), which was deposited on C45 carbon steel (the cathode) and molten by a laser beam. After surface treatment were analysed of changes in surface structure of the coat. Results of the research shows influence of parameters of this process to roughness, tribologic properties and morphology of the surface layer prepared by WC-Co coating and laser treatment.

Abstract: The solar reflective green coating is prepared in the paper, of which the tailored infrared property reaches near upon 80%, and the temperature reduction bring by the reflectivity of the coat is improved too. The experiments on the temperature reduction and aging performance of the coat are also performed, the results suggests the green solar reflective coating can reduce more than 10°C compared with the same type coatings, it also has a good aging resistance capability.

Abstract: To improve the dispersion of phthalocyanine blue powder, decrease its consumption and increase the use value of talc, TPBCP (Talc / Phthalocyanine Blue Composite Powder) was prepared by liquid phase mechanochemical method. By means of paint performance test, scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FT-IR), the properties and microstructure of composite powder were characterized. The hiding power and oil absorption value of talc/phthalocyanine blue composite powder were 12.88 g/m2 and 32.50 g/100g respectively, and the International Commission on Illumination (CIE) colorimetric data L, a, and b were 44.95, 1.65 and -17.18 respectively. It was equivalent for the hiding power of composite powder to 77.6% of that of pure phthalocyanine blue with a equivalent CIE. The formation of TPBCP was marked by phthalocyanine blue particles uniformly coated on talc surface. The results showed that TPBCP had similar performances with phthalocyanine blue and could instead of phthalocyanine blue to be applied in several fields.