Authors: Yu Xin Gao, Cheng Zhao, Zhi Gang Fang, Jian Yi
Abstract: Micro-nanostructure coatings have been attempted to prepare by Electro-spark deposition (ESD) on cast iron substrate. The microstructures and properties of the coating were investigated by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and microhardness tester. The results show that micro-nanosized particles and fine equiaxed structures prevail in the coating. The primary phases of the coating contain Fe3W3C, Co3W3C, Fe7W6 and W2C. Its average microhardness reaches 1290.1 HV. The results of abrasive test demonstrated that the coating had an excellent sliding wear resistance because the superfine particles distributed dispersedly in the coating increased the resistance to micro-cutting and plowing during the wear test, which effectively improves the surface performance of cast iron substrate.
176
Authors: Lan Yun Qin, Guang Yang, Wei Wang, Ming Tong, Xing Liang Wang
Abstract: TiC reinforced titanium matrix functionally graded materials (FGM) has been produced by processes of laser metal deposition through changing the powder feed rate of Ti and Cr3C2 powder. The OM, SEM, EDS methods were used to analyze the components and microstructure of the coatings. Microhardness and wearing resistance at room temperature of the FGM coating were examined by microhardness tester and wear tester respectively. The results show that FGM coating reinforced by in-situ TiC apparently improved hardness of Ti alloy; the microhardness can reach HV1100, and present gradient distribution along deposition direction. Dry sliding wear properties of these FGM coatings have been compared with substrate materials wearing. The observed wearing mechanisms are summarized and related to detailed microstructural observations. The results show the wear resistance of the coating can be improved by 46.6 times.
316
Authors: Sheng Zhu, Guo Feng Han, Xiao Ming Wang, Wen Bo Du
Abstract: In this study, Al-Si alloy protective coating was deposited on the surface of ZM5 magnesium alloy by cold spray technology. Researchers observed the surface morphology of the coating by SEM, and researched tribological properties of the substrate material and the coating. The results show that, the bonding mechanism of the Al-Si alloy coating and substrate is metallurgical bonding and mechanical interlocking. The abrasion mechanism of Al-Si alloy coating is adhesive wear. The friction coefficient of the coating is higher than magnesium alloy in different friction frequencies. Greater change in friction coefficient is caused by the inhomogeneous phase composition. But the wear track depth of the coating is smaller than magnesium alloy. Wear-resisting property is improved.
142
Authors: Fei Xiong Mao, Tao Liu, Shi Wei Liu, Jing Kun Yu
Abstract: Mg films were prepared by magnetron sputtering on zirconia substrate. The surface morphology, structure and adhesion performance were determined by scanning electron microscopy (SEM), X-ray diffraction (XRD) and automatic nano scratch tester, respectively. The results show that the Mg films deposited on the substrates at 50 °C, 200 °C, 300 °C are mainly of hexagonal phase with the crystal planes (002) in highly preferred orientation that is weaken with the substrate temperature increased. After annealed at 230 °C, the quality of thin film deposited on the substrate at 50 °C can be improved as crystallizability enhanced and grain size increased. The adhesion of Mg film increases firstly, and then decreases with increasing the substrate temperatures.
2834
Authors: Ren Guo Song, Pu Hong Tang, Chao Wang, Guo Lu
Abstract: Al2O3 and Al2O3-40wt.%TiO2 ceramic coatings on H13 hot-worked die steel have been prepared by plasma spraying, and then the microstructure, micro-hardness as well as wear resistance of the prepared coatings have been investigated by means of x-ray diffraction (XRD), scanning electron microscope (SEM), Vickers hardness tester and ball-on-disk high temperature tribometer. The results showed that the plasma sprayed ceramic coatings are of higher hardness and wear resistance than H13 hot-worked die steel.
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