Advanced Materials Research Vols. 750-752

Abstract: In this article, a series of the PVDF/PPTA blend membranes with porous structure and excellent performance were successfully prepared by the phase transformation method. The effect of the mass ratio of W(PVDF)/W(PPTA) was systematically investigated.The morphology of the blend membranes were examined using scanning electron microscope (SEM). The permeation performance was characterized by measuring pure water flux. Meanwhile, the mechanical properties of membranes were researched. The experiment results confirmed that the blending ratio is a major factor to influence the structure and performance of PVDF/PPTA blend membrane. The blend membranes possess much better permeability than pure PVDF membrane and fairly good the mechanical properties especially for the membrane made by PVDF : PPTA=6 : 1.

Abstract: Nano iron oxide thin films were prepared by both citric acid sol-gel and dip-coating method. The modifications of nano ferric oxide thin film materials were carried out by using PEG and bismuth nitrate . Both nano ferric oxide thin film materials prepared and the modified were characterized by SEM, XRD. It is indicated that that modification of wether PEG or bismuth nitrate to the thin film can reduce the convex surface and the thin film surfaces are more uniform.

Abstract: The large scale cable-membrane structure is widely used in the Expo Axis. The structure is composed of continuous triangle shaped membrane unit. The representative local part of membrane structure is selected to carry out double-layer membrane strength experiment and reduced-scale experiment to test its mechanical performance and strength index during tension. The results show that the bearing capacity of double-layer membrane structure is more than 1.8 times of single-layer membrane. Material strength and joint strength are all in agreement with the design. Through the analysis of membrane shape decision and membrane processing key technology, it is concluded that form-finding must be considered in membrane self-weight, and the reinforcement membrane and ontology membrane should be at the same direction.

Abstract: In this essay the authors are seeking to examine a chemical surface activation process for NiP electroless plating of poly (ethylene terephthalate) (PET) films without using palladium catalyst, during which the nickel particles have been chelated with the C=O and COH groups of the carboxymethyl cellulose (CMC) on the PET film that are acting as a catalyst center for the electroless plating.

Abstract: The investigation of physico-mechanical properties of metal-carbon (Cr-C and Mo-C) coatings obtained using pulsed vacuum arc deposition has been carried out. Changing the arc discharge pulse repetition rate of the individual plasma sources equipped with metal and graphite cathodes allows significant varying of the composition, surface roughness and friction coefficient of the coatings. When reducing the pulse repetition rate in metal plasma source from 10 Hz to 5 Hz while retaining that constant in carbon source, the metal content in the coating can be decreased from 30 at.% to 2 at. % with increasing the surface roughness by a factor of 3.5. The tribological investigations of Cr-C and Mo-C coatings under the dry friction conditions showed the uniform adhesive wear of the coating upper layers. The coefficient of friction measured against steel counterbody was in the range of 0.08 to 0.1. However, in this case Mo-C coatings were more wear-resistant than Cr-C coatings.

Abstract: For solving fatigue failure of surface on the metal parts, the Surface Nanocrystallization technology by pre-forceing rolling was developed. The feature and operaing principle of equipment were introduced. A nanocrystalline surface layer was fabricated on deposited layer by using pre-forceing rolling technology (PFRT) .The microstructure of treated specimens was characterized by using scanning electron microscopy and transmission electron microscopy. Experimental evidence showed, The obvious plastic deformation layer was observed, the thickness of deformation layer is about 15μm. A nanocrystalline surface layer was found after PFRT treatment. The grain size of equiaxed nanocrystallites with random crystallographic orientations on the top surface layer was about 10nm. Experimental analysis indicated the coars crystal in the surface layer could be refined into nanocrystalline by using the pre-forceing rolling technology, attaining optimizing surface structure of metal parts.

Abstract: Much attention has recently been focused on the microstructure inhomogeneity problems of the laser surface hardened layers.The GCr15 steel specimens were treated through laser transformation hardening technology. Rapid heating of austenite transformation and microstructure inhomogeneity was studied.The nouniform austenitic formation and the microstructure inhomogeneity problems is caused by uneven temperature field. The input power fluctuations and laser beam model also affect the quality of the laser quenching. Hardness value fluctuation is due to the uneven microstructure of the laser hardened layer. The results show that the grain size of laser hardening area and the distribution of carbides is not uniform. In the rapid heating cases, the atomic difusion process of carbon and alloy elements is not sufficiently, this causes no uniformity of the distribution of carbon and alloy composition .

Abstract: This paper briefly introduced the coating process that generally used in the domestic and overseas Color-coated lines, emphatically analyzed the surface defects of the Color-coated sheets that easily occurred during the production and the methods which can prevent those defects.

Abstract: Diamond-like carbon (DLC) and TiN coatings were deposited on the 304 austenitic stainless steel(SUS304) substrates by using unbalanced magnetron sputtering and arc ion plating techniques, respectively. The phase structure and surface morphology of coatings were characterized by SEM and XRD.The electrochemical corrosion of two coatings in different electrochemical solutions (including3.5%NaCl,10%HCl,20%NaOH) were investigated by electrochemical workstation.The result showed that DLC coating was amorphous structure and TiN coating was nano-crystalline structure.The surface of DLC coating was smooth and dense,while TiN coating existed pits.In 10%HCl and 3.5%NaCl solutions,the corrosion resistance of DLC coating increased by 4.16 and 10.9 times compared with SUS304 and increased by 5.16 and 1.11 times compared with TiN coating,respectively.But in 20%NaOH solution, the corrosion resistance of DLC was not superior to SUS304 and TiN coating.In 10%HCl solution,the corrosion resistance of TiN coating increased by 9.81 times compared with 304 SUS304.But in 3.5%NaCl and 20%NaOH solutions,the corrosion resistance of TiN coating was worse than SUS304.

Abstract: Effect of three kinds of RE ion (Y³⁺, Nd³⁺, La³⁺), which added separately in the Ni-P electroless deposition bath, on coating micro-structure and property such as microhardness, wear and corrosion resistance was investigated. Optimization of organization structure and property of coating attributed to RE-added was analysed by means of ICPM, XRD, SEM and micro-sclerometer, wear testing machine. The results show that the coating has still amorphous structure but higher of phosphorus content due to RE, which added in the bath can make coating grains smaller and more compact. At the same time, improved microhardness, wear and corrosion resistance of coating are observed with RE-added properly. The effect of Y³⁺ is most remarkable among three RE ions. When the concentration of Y³⁺ in the bath is 0.04g.L^-1, the microhardness, wear loss and corrosion rate in 10% H₂SO₄ solution of coating is 606HV, 4.9572mg and 0.0064mg.cm^-2.h^-1, respectively.