Advanced Materials Research Vols. 291-294

Abstract: A green corrosion inhibitor similar to polyepoxysuccinic acid is synthesized by using maleic anhydride and sodium allylsulfonate as raw material. The molecular structure is characterized by IR spectra. The efficiency of an environmental-friendly corrosion inhibitor for carbon steel in sea water is researched through method of weight loss. This new corrosion inhibitor is a mixture of multipolymer, Zn²⁺ and HEDP. The efficiency of the corrosion inhibitor for carbon steel in the sea water is 97.68%, when the concentration of multipolymer is 50mg/L, Zn²⁺ is 4mg/L, HEDP is 10mg/L. The surface of carbon steel is investigated by electron microscopy after the experiment of corrosion, and the mechanism of corrosion inhibitor is discussed.

Abstract: The hardness and the wear resistance of the nano-diamond composite coatings were investigated by the micro-hardness tester and the friction tester. The relationship of the nano-diamond concentration, heat treatment temperature and hardness were revealed. These results show that the composite coatings have higher hardness, better wear resistance and lower friction coefficient under the uniform dispersing of the nano-diamond in the nickel matrix. The maximum hardness of the composite coatings reaches HV654 when the nano-diamond concentration is 30%. Frictional coefficient is decreased from 0.185 to 0.16. Moreover, the hardness does not reduce under annealing at 300°C. The frictional mechanism of the composite coatings indicates that the worn nano-diamond could block the direct contact between the composite coating and the standard ring. Spherical nano-diamond particles play the role in the "micro-ball" among the contact surfaces, the frictional coefficient is reduced and the wear resistance is improved.

Abstract: The in-situ M₇C₃–TiC carbides reinforced Fe-based hardfacing coating had been produced by prepared high-carbon ferrochromium, ferrotitanium and graphite power on 20g steel through GTAW. The microstructure and hard phases morphology were investigated by means of OP, SEM and XRD. The results showed that the microstructure of hardfacing coating consists of lamellar martensite, TiC particles and M7C₃ complex carbides. The TiC particles with flower-like shape and M7C₃ complex carbides with hexagonal shape are observed in the coating. The hardfacing coating reinforced by M₇C₃ –TiC carbides revealed higher wear resistance than that of the substrate due to the presence of a high volume fraction of hard and wear-resistance primary M7C₃ carbide uniformly distributed in the fine and strong [M+M₇C₃+TiC] eutectics matrix.

Abstract: The research progress of the study on the material and technology of heat insulating coating was introduced. Parts of the research work were enumerated. The development trend of them was looked forward.

Abstract: Polyurethane (PU) coatings with additives, such as UV-curing monomers and oligomers, ultraviolet absorbing (UVA) and hindered amine (HALS), were accelerated with Xenon lamp to study the effect of additives on photo aging performance of PU coatings. The ageing behavior of samples was evaluated with gloss-meter, chromatic meter, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM).The results indicated that the anti-aging of coating was improved by the synergy effect of 1.5wt.% HALS(Tinuvin 292), 3wt.% UV-curing resin (611B-85) and 1wt.% UVA(UV1130).

Abstract: The Ni-P/SiC composite coating was prepared by chemical deposition technique. The corrosion behavior of electroless Ni-P/SiC composite coating was investigated. The results show that the corrosion resistance of electroless composite coating decreased with the increasing SiC concentration in bath solution. There were some little pores among the composite coating and the pores would increased with the increasing SiC content among the coating, which made the corrosion resistance decreased. The corrosion rate increased with the increasing temperature of corrosion liquid. The corrosion resistance was improved for T gradient electroless Ni-P/SiC composite coating comparing with the single electroless composite coating whether the corrosion solution was acid solution or alkaline solution. The corrosion rate were less than 5 mg/cm² for all specimens in alkaline solution, which indicated that the corrosion resistance of electroless composite coating was better than that in acid solution.

Abstract: Influence of the process parameters of a reactive mid-frequency dual-magnetron sputtering on surface defects of Cr_xO_y film was investigated. The forming mechanisms of the observed droplets and craters were analyzed. The optimal parameter combination for accomplishing fewer surface defects was explored; and the optimized process parameters evidently minimized the surface defects of the film. In the condition of the target current of 16 A, the gases pressure of 0.31 Pa, and the bias voltages in a range of -120~-240 V, an optimized Cr_xO_y film has been synthesized with surface defect density low to 78 defect/mm^-2.

Abstract: The ceramic thin film on the surface of LY12 aluminum alloy were prepared by the method of the microarc oxidation. The appearance of film was observed by stereoscopic microscope, the thickness of film was tested used thickness tester and the corrosion resisting property of sample in solution of 3.5% NaCl was measured by potentiostatic method. The results show that the tightness of film is best when used 8A/ dm² for micro-arc oxidation, the hardness is increased with the increase of current density. The corrosion resisting property of ceramic film in solution of 3.5% NaCl used different current density is different, the corrosion resisting property of ceramic film is first increased and then decreased with the increase of current density, the corrosion resisting property of ceramic film prepared with the current density of 8A/ dm² is best.

Abstract: A Ni-SiC nano-composite plating coating was prepared by using composite plating technology adding nano-SiC in the bath.Then the surface morphology was examined by scanning electron microscope (SEM), the transmission electron microscope (TEM) was used to study the grain size,the porosity, corrode-resistant, combines intensity and wearability of the composite plating coating were also tested and contrasted the result with the pure nickel coating. The results shows the surface of Ni-SiC composite coating are more uniform and compact for the adding of nano-Sic refined the grain, the wear resistance,microhardness and corrosion resistance of the composite coating are also significantly improved.

Abstract: The influence of manganese in Zn-Mn and Zn-0.2wt.%Al-Mn bath on the morphology and growth kinetics of the galvanizing coatings has been studied using scanning electron microscopy equipped with energy dispersive spectroscopy. When galvanized in zinc bath, the coating consists mainly h and ζphase. When manganese is added in zinc bath, the morphology of ζ phase changes from fragmental to compact. Manganese favors the formation of the δ phase and inhibits the growth of the ζ phase.When galvanized in Zn-0.2wt.%Al bath, the coating consists only δ and h phase. With the addition of manganese in Zn-0.2wt.%Al bath, the morphology of δ phase changes from fragmental to compact The thickness of the Fe-Zn intermetallic phase layer in coatings decreases obviously when manganese is added into zinc and Zn-0.2wt.%Al bath, and the thickness increases slowly with the increase of immersion time.