| GONG Yun-bai,WANG Ping,XU Zhang-xin,WU Ting,GONG Ze-yu,YANG Biao,HU Jie,XIONG Dan,LIU Ji-wei.Effects of Phytce Acid Additives on the Characteristics of Micro-arc Oxidation Coatings on 6061 Aluminum Alloy[J],50(12):381-389 |
| Effects of Phytce Acid Additives on the Characteristics of Micro-arc Oxidation Coatings on 6061 Aluminum Alloy |
| Received:December 09, 2020 Revised:April 20, 2021 |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2021.12.038 |
| KeyWord:6061 aluminum alloy micro-arc oxidation phytic acid microstructure corrosion resistance thermal shock resistance |
| Author | Institution |
| GONG Yun-bai |
School of New Energy and Materials, Southwest Petroleum University, Chengdu , China |
| WANG Ping |
School of New Energy and Materials, Southwest Petroleum University, Chengdu , China |
| XU Zhang-xin |
School of New Energy and Materials, Southwest Petroleum University, Chengdu , China |
| WU Ting |
Centre for Materials and Coastal Research, Helmhotz-Zentrum HEREON, Geesthacht 21502, Germany |
| GONG Ze-yu |
School of New Energy and Materials, Southwest Petroleum University, Chengdu , China |
| YANG Biao |
School of New Energy and Materials, Southwest Petroleum University, Chengdu , China |
| HU Jie |
School of New Energy and Materials, Southwest Petroleum University, Chengdu , China |
| XIONG Dan |
School of New Energy and Materials, Southwest Petroleum University, Chengdu , China |
| LIU Ji-wei |
School of New Energy and Materials, Southwest Petroleum University, Chengdu , China |
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| Abstract: |
| This paper aims to improve the properties of micro-arc oxidation (MAO) coatings on 6061 aluminum alloys. In this paper, micro-arc oxidation (MAO) coatings on 6061 aluminum alloys were modified by adding 5 mL/L phytic acid in electrolytes. The voltage-time curve during the micro-arc oxidation process was recorded, and the effects of adding phytic acid on the surface morphology, element composition, phase composition, corrosion resistance, thermal shock resistance and other coatings characteristics of the MAO coatings were studied by using SEM, EDS, XRD, electrochemical workstation, muffle furnace, etc. After adding phytic acid, the micro-arc oxidation voltage was increased from 526 V to 538 V, the micro-arc oxidation discharge was more uniform, and the growth rate of the MAO coatings increased, which improved the coatings thickness from 9.3 μm to 13.6 μm. Meanwhile, diameter of the discharge micropores is reduced, the number is increased, coatings surface is dense and uniform, the bonding force of MAO coatings is enhanced from 3.2 N to 3.9 N, and the microhardness is improved by 39.2HV. Phosphate groups and hydroxyl groups in phytic acid can combine with Al3+ ionized from the matrix to form aluminum phytate, which increases the ratio of C and P elements in MAO coatings and reduces the ratio of Al elements. During the micro-arc oxidation process, the Al in the matrix transforms into γ-Al2O3 and α-Al2O3. After adding phytic acid, the diffraction peak intensity of γ-Al2O3 and α-Al2O3 increases. The corrosion rate of MAO coatings is increased from 1.085×10–2 mm/a to 1.565×10–3 mm/a, the corrosion resistance is improved, simultaneously has good thermal shock resistance. The addition of phytic acid optimizes the structure of MAO coatings, increases the thickness, microhardness and bonding force of coatings, and improves the corrosion resistance and thermal shock resistance of coatings. |
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