| LI Zhong-sheng,WU Hu-lin,CHEN Hai-tao,CONG Da-long,ZHANG Min,HE Qing-bing,PENG Dong.High Melting Point Composite Coating of W-Mo Alloy Synthesized by Electrospark Deposition on Steel Surface[J],52(10):250-258 |
| High Melting Point Composite Coating of W-Mo Alloy Synthesized by Electrospark Deposition on Steel Surface |
| Received:September 21, 2022 Revised:January 09, 2023 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.10.020 |
| KeyWord:electrospark deposition tungsten molybdenum ablation resistant coating mass ablation rate linear ablation rate |
| Author | Institution |
| LI Zhong-sheng |
Southwest Institute of Technology and Engineering, Chongqing , China |
| WU Hu-lin |
Southwest Institute of Technology and Engineering, Chongqing , China |
| CHEN Hai-tao |
Southwest Institute of Technology and Engineering, Chongqing , China |
| CONG Da-long |
Southwest Institute of Technology and Engineering, Chongqing , China |
| ZHANG Min |
Southwest Institute of Technology and Engineering, Chongqing , China |
| HE Qing-bing |
Southwest Institute of Technology and Engineering, Chongqing , China |
| PENG Dong |
Southwest Institute of Technology and Engineering, Chongqing , China |
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| Abstract: |
| The high melting point composite coating of W-Mo alloy with a thickness of 100 μm was prepared on the surface of PCrNi3MoVA steel by ZY-10 type EDM surfacing/coating deposition equipment, with tungsten and molybdenum rods as electrodes and ultrapure argon as protective gas. In terms of technology, a molybdenum coating of a certain thickness was firstly deposited on the surface of the PCrNi3MoVA steel substrate as the primer, and then tungsten coating was deposited on the surface of molybdenum coating. Since tungsten had a higher melting point and hardness than molybdenum, it was more difficult to deposit tungsten coating on the surface of PCrNi3MoVA steel substrate. During deposition of tungsten coating, parameters such as pulse voltage, deposition frequency and duty cycle higher than those of molybdenum coating were used. The pulse voltage was above 60 V, deposition frequency was 700-800 Hz, duty cycle was 50%, molybdenum and tungsten electrodes were 3 mm. The micro morphology of the surface and cross section of the composite coating were observed by type QUANTA 200 environment scanning electron microscope from FEI and metallographic microscope, the composition of the composite coating was analyzed by INCA energy dispersive spectrometer from OXFORD, and the phase composition of the composite coating was analyzed by EMPYREAN X-ray diffractometer from PANalytical. The ablation resistance of the W-Mo high melting point composite coating was tested by a new type of plasma flame simulation ablation test system developed by the Southwest Institute of Technology and Engineering. The equipment relied on the ultra-high temperature plasma jet to vertically burn the surface of the sample, ablate or burn through the materials to be tested, measure the back surface temperature and ablation time during the ablation process of the sample, measure the thickness and mass change of the sample before and after the test, and calculate the linear ablation rate, mass ablation rate and other indicators of the sample. The results indicated that W-Mo high melting point composite coating was successfully synthesized on the surface of PCrNi3MoVA steel substrate by the electrospark deposition process. The ablation resistance of the composite coating was good. The linear ablation rate in the first 10 seconds was 0.090-0.267 mm/s. The thickness of the composite coating is greatly affected by the deposition times and deposition voltage. The composite coating is mainly composed of W, Mo, Fe and other components, and the closer to the coating surface, the higher the content of W and Mo elements. The composite coating is mainly composed of Mo, MoC, Fe2Mo3, Fe2W and other phases. The microstructure of the composite coating is compact, uniform and continuous and no cracks, holes and other defects are found on the coating, forming a good metallurgical bond with the steel substrate. The composite coating can withstand the high temperature short-time impact and erosion of the plasma flame, and the increase of the composite coating thickness can effectively inhibit the increase of the coating ablation rate, improving the ablation resistance. |
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