Abstract: Storage tank was protected from corrosion with the combined method of thermal spraying and coating, and corrosion resistance of the coating was studied through on-the-spot static weight loss method, potentiodynamic polarization curve and electrochemical AC impedance test. The result showed that the hanging slices with thermal sprayed aluminum powder, glass flake and epoxy resin coating had least weight loss and best corrosion resistance after 10 months of corrosion with on-the-spot weight loss experiment. In the polarization curve experiment, the anodic polarization curve of the hanging slices with thermal sprayed aluminum powder and glass flake had passivation characteristics, strong polarization area shifted left, weak corrosion current and greater polarization resistance. In the AC impedance spectra, hanging slices with thermal sprayed aluminum powder and glass flake had greater capacitive reactance arc and better corrosion resistance.
Abstract: This study deals with fretting wear behavior of 40CrNiMoA steel on a SRVⅣoscillating friction and wear tester. The results indicate that with the frequency and load increasing, both the friction coefficient and fretting wear volume increase. With the amplitude increasing, the fretting wear volume increased too, but the effect of amplitude on friction coefficient was not simple positive correlation according to the experimental results. Meanwhile, the fretting wear mechanism is directly related to test frequency, load and amplitude. When they are small, the main fretting wear mechanism is abrasive wear, with these test parameters increasing, the main fretting wear mechanism turns to a combination of abrasive wear and adhesion wear. Based on the experimental results, the anti-fretting wear measures of steel worm gear pairs used in mechanical tracked regulator of tracked vehicle are discussed.
Abstract: In this paper, effects of anticipated heat treatment on the electroless nickel plating coated on magnesium alloys AZ91D were investigated by using heat treatments of solution (T4) and solution + aging (T6) before electroless nickel plating. The influence of anticipated heat treatment on the structure, composition and anti-corrosion property of electroless coating were studied by using Scanning Electrical Microscope (SEM), EDS and Corrodkote corrosion test. It is shown that compared with the as-casted magnesium alloys and samples treated with T4, the deposition rate of Ni, the P contained in the coating and the anti-corrosion property of samples treated with T6 are the highest for the given system studied, and T6 treatment can promote the anti-corrosion property of the coating effectively.
Abstract: In order to solve the problem of diamond film crack when deposited on molybdenum substrate to improve the preparation quality of diamond film and the rate of finished products , the distributions of thermal residual stress components in diamond film and at interface between the film and molybdenum substrate were simulated by finite element method in the case of whether to consider the plastic deformation of molybdenum substrate or not, moreover, the influence of thermal residual stress upon the failure of film was analyzed. Results show that thermal residual stress is more coincidental with experimental data when the plastic deformation of molybdenum substrate is considered. There are large tensile radial stress and tensile axial stress in the vicinity of upper surface of the film, which is the primary cause for the film to crack.
Abstract: Electroless plating technology used to alleviate fretting damage of titanium alloy was studied, Ni-Tl-B coatings were prepared, process optimization was worked out by the orthogonal table, deposition rate and solution consumption per hour and the initial friction coefficient and the bearing cycles under a low friction coefficient were chose as the index to calculate the range according to the economical efficiency and the application of coating under the surface morphology analysis and the fretting friction coefficient test, optimum process was finally worked out. Surface morphology was analyzed by TM-1000 scanning electron microscope and the fretting friction coefficient was tested by the DELTALAB-NENE fretting wear tester. The results shows that the surface morphology of the Ni-Tl-B coating are all typical cell structure which will be slightly different when the process changes and the optimum Ni-Tl-B coating has outstanding fretting damage resistance.
Abstract: As more and more special refractory materials apply to laser processing technology, many processing problems have highlighted, this article studies on how to improve the laser absorption rate in the processing of work piece, and proposes the method of nanometers particles attached to improve absorption efficiency of laser materials before the laser processes smooth surface work piece materials, to analysis and forecast the theoretical effects. Through the laser processing energy loss analysis and research, we can identify the major loss of laser processing means. Combined with the most commonly used laser processing smooth work piece surface pretreatment method deficiencies and some characteristics of nano-coating, nano-coating will focus on the process of laser processing to further improve the efficiency of heat absorption to provide a new way of settlement.
Abstract: The self-propagating spraying coating was prepared by Self-propagating High-temperature Synthesis(SHS). The effects of the rare earth(RE) on microstructure and the abrasive resistence of self-propagating spraying coating was investigated. The obve1rvations and analysis of the microscopic appearances of the worn surfaces of the coating were conducted by the use of SEM. The results showed: the RE can impove the properities of the self-propagating spraying coating, the suitable small amount(0.2%) of RE can refine the self-propagating spraying coating and improve the hardness and the wear resistence efficiently. When the excessive RE(0.5%) was added into the self-fluxing alloy power, the properties of the self-propagating spraying coating became worse.
Abstract: Camouflage coatings method and its features are described. Concrete way of camouflage for construction machinery is presented. Aiming at the actual situation and in association with practical experiences, concrete methods to design and optimize camouflage for construction machinery are suggested.
Abstract: An inline hot rolling was operated on 5182 aluminum alloy strip cast using a vertical type high speed caster (VHSTRC) at the speed of 60 m/min. A porosity existing at center line of the thickness and a ripple mark on the surface, these are typical defects of the strip cast by the VHSTRC, could be improved by the inline rolling. The rolling speed was as same as the roll-casting-speed of 60m/min. The temperature of the strip, when the inline rolling was operated, was 450oC. The reduction of the strip of the inline rolling was 35%.
Abstract: Roll casting of Al-SiCp composite alloy strip was tried using a vertical type high speed twin roll caster equipped with mild steel rolls. The Al-20vol% SiCp and Al-30vol%SiCp alloy could be roll-cast to the strip. The casting speed was 30m/min. The thickness of as-cast strip was thinner than 2.5mm. The SiCp powder was dispersed uniformly at the thickness direction. The as-cast strip could be thin down to 1mm by the hot rolling and the cold rolling without broken.