Advanced Materials Research Vols. 1004-1005

Abstract: To improve the anti-corrosion properties of the AZ91D magnesium alloy, the electroless plating Ni-Co-P on the AZ91D magnesium alloy is necessary. The influences of additives (ammonium fluoride (NH₄F) and hexamethylenetetramine (HMTA)) on deposition rate, corrosion rate, acid resistance, corrosion current, corrosion potential and webster hardness of electroless plating Ni-Co-P alloy coating, were investigated using electrochemical methods, etc. The results show that the deposition rate and corrosion resistance properties of electroless plating Ni-Co-P are obviously improved when the additives, including NH₄F (2%) and hexamethylenetetramine (HMTA, 1%), are added into plating solution, respectively. In addition, the global particles in the Ni-Co-P coating become smaller with the addition of NH₄F by comparison with no additives and coatings are dense, uniform and defect-free.

Abstract: The equipment for two-color camouflage mode stone chip coated roof tiles is designed as an improvement on the equipment of single-color coated steel roof tiles, which uses two different colors (color 1 and color 2) contained in a certain funnel to replace the original single color funnel. The feedings of the stone chips Q_sc1 and Q_sc2 are separately controlled by the motor M_r1 and M_r2 but are interconnected. When the feeding amount of stone chip color 1, Q_sc1, is designed to change in sinusoidal, the feeding amount of stone chip color 2, Q_sc2, is controlled by Q_sc1, but the total amount Q_sc1+Q_sc2 is kept be a constant at any time. In this way, a colorful coating with a uniform thickness can be obtained. The amplitude and frequency of the parameter in the sine wave represent the contrast and the hue of the camouflage coated steel roof tiles.

Abstract: In this study, the AISI410 martensitic stainless steel was treated by plasma nitriding. Three different temperature were employed (420°C ， 460°C， 500°C) for 6h. The microstructure, hardness and corrosion properties of the nitrided samples were characterised by a variety of analytical techniques. The result shows that the hardness of the nitrided samples is four times the size of the untreated samples and the thickness of the compound layer will decline when the nitriding temperature increases. In the electrochemical corrosion tests, the samples nitrided at 420°C and 460°C showed lower current density and corrosion rate than the original sample because of the formation of nitrided compound layer on the martensitic stainless steel. In particular, the corrosion properties of nitriding samples(420°C) are five times larger than original samples. But it reducesnitriding at high temperature(500°C) because of the precipitation of chromium.

Abstract: The NiCoCrAlY+WC12Co coating with high density was prepared on the surface of the magnesium alloy by cold spraying. Effects of the WC12Co content on the wear behavior of coating were studied. The results showed that, under the dry friction condition, the weightlessness of wear of the coating with 20%WC12Co was smallest. The weightlessness of wear of the coating with 10%WC12Co was worse than that with 20%WC12Co. However, the weightlessness of wear of the coating without any WC12Co was worst among the three coatings. After the frictional experiment for 20 minutes, the weightlessness of wear of coating without any WC12Co was 10mg. Compared with that of coatings with 10%WC12Co and 20%WC12Co, the weightlessness of wear was lower than 35% and 54%, respectively. Obviously, the coating with 20%WC12Co had the capacity of the weightlessness of wear resistance. Consequently, the more the coating with WC12Co was, the higher the capacity of the weightlessness of wear resistance was.

Abstract: The process of zinc immersion for Mg-Li alloy is researched in this paper. Through orthogonal experiments, the optimum process parameters are obtained. The microstructure and the composition of the Zn-dipped coating were measured with SEM, XRD, EDS and electrochemical testing. Results show that, the optimum process parameters are: concentration of main salt (ZnSO₄) is 40g/L; solution temperature is 60°C; dipping time is 5min. In addition, dipping time is the most influential factor, then is solution temperature, the last is the concentration of main salt.

Abstract: The water-based paint had been examined to prepare a new chromate-free insulating coating on silicon steels. The structure of the insulating coating was characterized by scanning electron microscopy, energy dispersive spectroscopy and infrared spectroscopy. Adhesion, high temperature annealing, and surface insulating resistance were measured. Corrosion resistance was investigated by neutral salt spray test and electrochemical test. Results exhibited that the insulating coating had excellent comprehensive performance. The adhesive level was 5B degree; the high temperature annealing test showed no coating degradation after heat treatment of 2 h at 450 °C in air or at 750 °C in nitrogen; the salt spray test showed the corrosion area was less than 2 % after the 12 h salt spray; when the coating thickness was 1.0-1.2 μm, the surface insulating resistance value was 380-420 Ω/mm².

Abstract: In situ synthesized TiC-TiB₂ reinforced Ni based coating was fabricated by argon arc cladding on Q235 steel substrate using titanium, boron carbide, Ni60 as the precursor powders. The phase composite on and microstructure of the clad layer were investigated by means of X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and Energy Dispersive Spectrometer (EDS). The results show that uniformly distributed TiC particles with the black petals shape and TiB₂ particles with rod shape could be synthesized by the situ reaction. Compared to those unreinforced Q235 steel substrate, the hardness and the wear resistance of TiC-TiB₂ reinforced Ni based composite coating were significantly enhanced.

Abstract: Accelerate the corrosion of the nanometer organic coating by design salt spray test. Research the corrosion resistance of the nanometer organic coating in grotto environment by EIS. The results show that prolong time of the salt spray test, the coating surface become to coarseness, the colour occur slight change, but no blistering and flake away. The Rc and Rt descend, every ten days the corrosion rate of coating augment decuple, at forty days is 3.14μm/a and the steel is not corrosion. The nanometer organic coating behave good protection ability and corrosion resistance in the grotto environment.

Abstract: A low-cost non-vacuum process for fabrication of Cu₂SnSe₃ film by sol-gel method and knife-coating process is described. First, a certain amount of Copper (I) chloride and tin (IV) tetrachloride was dissolve into the mixture of water and alcohol and then some Polyvinyl Pyrrolidone (PVP) was added to the solution to obtain based colloidal solution. Next, precursor thin layer was deposited by knife-blading technique on soda-lime glass (SLG). Finally, precursor layer was annealed at selenium flow atmosphere carried by Ar gas at 550^oC. Through X-ray diffraction (XRD) and Raman spectra, it is found that pure Cu₂SnSe₃ film was prepared successfully. Scanning electron microscopy (SEM) and UV–vis–NIR absorbance spectroscopy were used to characterize its morphology and optical bandgap.

Abstract: Zirconium aluminum nitride coatings have been deposited onto Ti-6Al-4V substrates by reactive magnetron sputtering in order to investigate the influence of Al-content on the microstructure and mechanical properties. The morphology and microstructure of the coatings were investigated by field emission scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Nanoindentation and Vicker’s indentation methods were employed to measure the hardness and toughness of the coatings, respectively. The results show that a structure of single cubic phase with twinning is formed at Al content of x ≤ 0.23, and a two-phase structure of hexagonal and cubic phase is formed at Al content of x ≥ 0.47. Hardness and toughness of the Zr_1-xAl_xN coatings show similar tendency with the increasing of Al-content. Both of them reach the maximum values at x=0.23 and drop to the minimum values at x=0.47, after that, they slightly increase with the increasing Al-content. The enhanced hardness and toughness achieved at x=0.23 is ascribed not only to single cubic phase structure but also to twinning structure.