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3675 |
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Effect of substrate and powder size on mechanical properties of vacuum cold sprayed Al2O3 coatings |
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Yu-Yue Wang* / State Key Laboratory for Mechanical Behavior of Materials, Xian Jiaotong University, China H.-F. Zhou / State Key Laboratory for Mechanical Behavior of Materials, Xi, China J. Zheng/ State Key Laboratory for Mechanical Behavior of Materials, Xi, China C.-J. Li/ State Key Laboratory for Mechanical Behavior of Materials, Xi, China G.-J. Yang/ State Key Laboratory for Mechanical Behavior of Materials, Xi, China |
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Vacuum cold spray (VCS) process was applied to fabricated Al2O3 coatings on aluminum, stainless steel and glass substates by using ±-Al2O3 powders with two particle size of 80 nm and 400 nm at the room temperature. The microstructure of original powders and coatings were characterized by scanning electron microscopy and transmission electron microscopy respectively. Crystalline phase of coatings were determined by X-ray diffractometry. The microhardness and Youngs moudulus of VCS Al2O3 coatings were measured by a nanoindentation method. The results demonstrate that the hardness of coatings deposited with 400 nm Al2O3 powders is nearly two times higher than that of coatings deposited with 80 nm Al2O3 powders, about 7.5 GPa due to different deposition mechanisms for two powders. And the Young's modulus of the former of 99 GPa is slightly higher than that of the latter. The microhardness of Al2O3 coatings on aluminum and glass substrate is 7.0 and 6.3 GPa respectively. The Young's modulus up to 120 GPa of coatings is hardly influenced by different substrates, which is about one-third of Al2O3 block materials. |