Advanced Materials Research Vols. 189-193

Abstract: PVDF was blended with PVC to improve the weldable property of PVDF topcoat. Effects of film formation process on the surface properties of PVDF/PVC blended film were investigated. Peeling strength of PVDF/PVC blended film has reached the internationally accepted standards (144.3N/5cm) when PVC concentration was 30%. Based on the “lotus effect” principle, PVDF/PVC film was hydrophilic modified by alkali solution and then grafted with alkyl chlorosilane to fabricate the micro- and nano-structures as the surface of lotus leaf. After grafting, contact angle of PVDF/PVC blended film was as high as 152.8°, and self-cleaning test showed dusts on this film surface can be easily taken away by water droplet when PVDF/PVC blended film was titled less than 1°.

Abstract: A process in anodic oxidation with high current density and wide temperature range was researched for high speed forming film on the top surface of aluminum piston. The oxidation parameters is a concentration of 18% H₂SO₄ solution-based liquid, current density of 5.5～8A/dm², temperature range－5～20°С , the oxidation time for the 0～60min. Pulse power and cooling equipment co-work to produce the film thickness up to 107μm, film speed was about 1.78μm / min. SEM indicates that the porous layer was made of the regular array columnar “cells” which parallel arrange and grow perpendicular to substrate.

Abstract: This paper presents the usage of vibration in laser direct deposition of Ti64. The vibration is used to refine the crystalline structure of the deposition. The vibration device vibrates in the laser deposition system along the Z axis. A design of experiments approach is applied in studying the effect of vibration on the deposited material. Vibration during deposition led to grain refinement and an increase in microhardness over that of samples from no-vibration. Also, vibration frequency is a significant factor. From the experiment results, it is found that a vibration frequency greater than 20Hz is desirable.

Abstract: The in-situ ceramic phases reinforced Fe-based surface coating had been produced by prepared high-carbon ferrochromium, ferrovanadium and graphite power on 20g steel through plasma transferred arc weld-surfacing process(PTA). The microstructure and properties were investigated by means of optical microscopy(op), scanning electron microscopy(SEM), X-ray diffraction(XRD) and microhardness meter. The results showed that the substrate and the coating formed good metallurgical bonding.The microstructure of coating consists of primary M7C3 carbide and eutectic structures[M+γ′+M7C3+VC]. The primary hexagonal (Fe,Cr,V)7C3 with larger size evenly distributed in coating and the fine VC particles were globular shape. The microhardness appeared reasonable distribution from substrate to the top ,which ensured that the materials had good abrasive wear resistance.

Abstract: In order to increase cavitation erosion resistance of fluid machinery, an iron-based coating was prepared by high velocity arc spraying (HVAS) on the surface of 1Cr18Ni9Ti stainless steel. The microstructure and performance were investigated respectively by optical microscope (OM), X-ray diffraction (XRD), scanning electron microscope (SEM), Vickers hardness and vibratory cavitation apparatus. The results indicated that the coating had the higher hardness (8.67GPa) and the finer structure than ZG230-450 (1.86GPa) used actual in water conservancy. Compared with ZG230-450, cavitation erosion resistance of the coating was better, and the coating presented flakiness stripping mode. The results indicated that the HVAS is a promising method to prepare the cavitation resistance coating.

Abstract: Mo₂FeB₂ Cermet Coating was deposited on Fe substrate by react flame spraying (RFS) process. Three different groups of specimens were prepared according to the change of induction heating treatment time. Comparative study of phase composition, microstructure, interfacial microstructure and bond strength of Mo₂FeB₂ Coating was carried out. X-ray diffractometry (XRD) and Scanning electron microscopy (SEM) were used to characterize the Mo₂FeB₂ coating. The bond strength between the coatings and Fe substrates was measured with the pull-off test method according to the corresponding GB 8642-88 standard. Results indicated that the time of induction heating treatment greatly affected the microstructure, interfacial microstructure and bond strength of Mo₂FeB₂ coating. 13 seconds of induction heating treatment favoured the formation of a compact Mo₂FeB₂ Coating with the highest bond strength of approximately 60 MPa.

Abstract: With the melt grafting method using styrene (St) as co-monomer to maleic anhydride (MAH)，the VERSIFY (V ethylene-propylene copolymer of the content of ethylene is 12%) was grafted. Different graft yield materials, V-g-(MAH-co-St) (g-V) were obtained. Nylon 6 (PA6)/ PP blends were prepared using twin-screw extruder. Using MFR, SEM, IR and mechanical properties testing analysis methods, morphology and mechanical properties of PA6/PP blends were studying on the different graft yield g-V. The results showed with increasing the graft yield, the minimum melt flow rate decreased and the size of the PP dispersed phase became smaller and more uniform. The addition of taller graft yield materials remarkably improved that the anhydride group in g-V reacted with the amine end groups of the PA6, and PP-PA6 copolymers were formed in situ, which effectively improved the compatibility between PP and PA6. The size of PP domains in the PA6 matrix was significantly reduced. Multi-monomer melt grafting can obtain a high rate of graft material. From the MAH: St = 0.5 to the MAH: St = 1, the grafting yield increased significantly. Continuing to improve MAH: St ratio, the magnitude of changes of graft yield of grafting decreases. Different grafting yield of multi-monomer g-V toughened PA6, a high rate of graft effect was good.

Abstract: The use of L27 (3⁵) orthogonal to the battery shell injection molding process is optimized. The main factors of technical parameters were determined mould temperature, melt temperature, the speed of injection, injection pressure, cooling time.On the basis of actual production, to determine the factors values of different process parameters.Combination of scrapped products in key (reduction and a high degree of tolerance deflated) tests were selected in the process parameters within the scope of the assessment. Various factors impact on the product of the total height followed by cooling time, mold temperature, melt temperature, injection pressure, injection speed from strong to weak .The best products technological parameters were determined.Good results were obtained for production.

Abstract: This paper uses cellular element method to propose a new calculating method for drill string dynamic model, and applies the calculating method on rigid packed hole assembly model. The results show that, this method has advantages of programming simply, applying boundary condition easily and rapid convergence rate. It is a new method for rigid packed hole assembly optimization design.

Abstract: In this paper, a robust tetrahedral mesh generation method based on Advancing Front technique is proposed. The proposed method inherits advantages of Delaunay method and Advancing Front method, such as efficiency of Delaunay method and maintaining the given boundary triangle mesh exactly of advancing front method. Tetrahedral mesh is generated from the given triangle surface mesh. This method mainly includes three stages. Firstly, the minimum container box of the triangular surface mesh is calculated and points are inserted into the box. Then the proper point is selected out to generate tetrahedron’s layers from surface to the interior volume of the model, so g the surface mesh can be maintained. The operation is simplified, and calculation efficiency is also higher than common Advancing Front method. At last, triangle intersection is examined. This technique allows generating the tetrahedral mesh with high quality elements with surface mesh preservation. A shoes model with both convex and concave surface is chosen for the experiment. The result clarified the robust and high efficiency of the proposed algorithm.