Tribological Synergism of Anodic Aluminum Oxide Surface Containing Micro-Holes and Nanopores under Lubricated Reciprocation
Micro-drilled aluminum surfaces containing micro-holes were anodized to produce nanopores over the machined and lapped surfaces. The anodized nanopores had an approximate diameter of 30–40 nm and a depth distribution of 20–30 μm from the surface. The diameter and depth of the machined micro-holes we...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-12-01
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| Series: | Lubricants |
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| Online Access: | https://www.mdpi.com/2075-4442/11/12/533 |
| _version_ | 1797380287613632512 |
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| author | Minhaeng Cho |
| author_facet | Minhaeng Cho |
| author_sort | Minhaeng Cho |
| collection | DOAJ |
| description | Micro-drilled aluminum surfaces containing micro-holes were anodized to produce nanopores over the machined and lapped surfaces. The anodized nanopores had an approximate diameter of 30–40 nm and a depth distribution of 20–30 μm from the surface. The diameter and depth of the machined micro-holes were 125 μm and 300 μm, respectively. Anodization itself did not change the surface roughness because the nanopores were very small. Ball-on-disk reciprocating tests were performed under lubricated conditions for 2 h using a frequency of 2 Hz, a load of 2 N, and a travel distance of 5 mm. The results showed that both the micro-drilled and anodized surfaces greatly reduced the coefficient of friction compared with the lapped bare surface; however, the coefficient of friction of the hole-textured specimen was not maintained till the end. Contrary to expectations, the lubricant retention capability of the textured structure declined because of hole failure that occurred during oscillation. This gradually increased friction until the end of the reciprocating test. When the micro-drilled surface was anodized, the coefficient of friction decreased again, implying that non-anodized micro-holes alone were ineffective for reducing friction. The surface hardness of Al increased owing to anodization, and thus the micro-holes remained intact. Therefore, it is concluded in this study that a prerequisite for friction reduction in Al is to increase the hardness to minimize the failure of micro-holes, which can be achieved by anodization. The synergistic lubricant retention capability can be maintained by the presence of both nanopores and micro-holes. |
| first_indexed | 2024-03-08T20:35:12Z |
| format | Article |
| id | doaj.art-cad8a5e8b7fb45ba9770d46507d9e8ec |
| institution | Directory Open Access Journal |
| issn | 2075-4442 |
| language | English |
| last_indexed | 2024-03-08T20:35:12Z |
| publishDate | 2023-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Lubricants |
| spelling | doaj.art-cad8a5e8b7fb45ba9770d46507d9e8ec2023-12-22T14:21:50ZengMDPI AGLubricants2075-44422023-12-01111253310.3390/lubricants11120533Tribological Synergism of Anodic Aluminum Oxide Surface Containing Micro-Holes and Nanopores under Lubricated ReciprocationMinhaeng Cho0School of Mechanical Engineering, Chung-Ang University, Seoul 06974, Republic of KoreaMicro-drilled aluminum surfaces containing micro-holes were anodized to produce nanopores over the machined and lapped surfaces. The anodized nanopores had an approximate diameter of 30–40 nm and a depth distribution of 20–30 μm from the surface. The diameter and depth of the machined micro-holes were 125 μm and 300 μm, respectively. Anodization itself did not change the surface roughness because the nanopores were very small. Ball-on-disk reciprocating tests were performed under lubricated conditions for 2 h using a frequency of 2 Hz, a load of 2 N, and a travel distance of 5 mm. The results showed that both the micro-drilled and anodized surfaces greatly reduced the coefficient of friction compared with the lapped bare surface; however, the coefficient of friction of the hole-textured specimen was not maintained till the end. Contrary to expectations, the lubricant retention capability of the textured structure declined because of hole failure that occurred during oscillation. This gradually increased friction until the end of the reciprocating test. When the micro-drilled surface was anodized, the coefficient of friction decreased again, implying that non-anodized micro-holes alone were ineffective for reducing friction. The surface hardness of Al increased owing to anodization, and thus the micro-holes remained intact. Therefore, it is concluded in this study that a prerequisite for friction reduction in Al is to increase the hardness to minimize the failure of micro-holes, which can be achieved by anodization. The synergistic lubricant retention capability can be maintained by the presence of both nanopores and micro-holes.https://www.mdpi.com/2075-4442/11/12/533anodic aluminum oxidemicro-machiningsurface texturingnanoporemicro-holereciprocating test |
| spellingShingle | Minhaeng Cho Tribological Synergism of Anodic Aluminum Oxide Surface Containing Micro-Holes and Nanopores under Lubricated Reciprocation Lubricants anodic aluminum oxide micro-machining surface texturing nanopore micro-hole reciprocating test |
| title | Tribological Synergism of Anodic Aluminum Oxide Surface Containing Micro-Holes and Nanopores under Lubricated Reciprocation |
| title_full | Tribological Synergism of Anodic Aluminum Oxide Surface Containing Micro-Holes and Nanopores under Lubricated Reciprocation |
| title_fullStr | Tribological Synergism of Anodic Aluminum Oxide Surface Containing Micro-Holes and Nanopores under Lubricated Reciprocation |
| title_full_unstemmed | Tribological Synergism of Anodic Aluminum Oxide Surface Containing Micro-Holes and Nanopores under Lubricated Reciprocation |
| title_short | Tribological Synergism of Anodic Aluminum Oxide Surface Containing Micro-Holes and Nanopores under Lubricated Reciprocation |
| title_sort | tribological synergism of anodic aluminum oxide surface containing micro holes and nanopores under lubricated reciprocation |
| topic | anodic aluminum oxide micro-machining surface texturing nanopore micro-hole reciprocating test |
| url | https://www.mdpi.com/2075-4442/11/12/533 |
| work_keys_str_mv | AT minhaengcho tribologicalsynergismofanodicaluminumoxidesurfacecontainingmicroholesandnanoporesunderlubricatedreciprocation |