{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,10]],"date-time":"2026-09-10T05:06:50Z","timestamp":1789016810319,"version":"build-2803163510"},"reference-count":35,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T00:00:00Z","timestamp":1788825600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"crossref","award":["52475231"],"award-info":[{"award-number":["52475231"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"crossref"}]},{"award":["52475231"],"award-info":[{"award-number":["52475231"]}],"id":[{"id":"https:\/\/ror.org\/01h0zpd94","id-type":"ROR","asserted-by":"publisher"}]},{"name":"Ningbo Youth Science and Technology Talent Cultivation Program","award":["2025QL024"],"award-info":[{"award-number":["2025QL024"]}]},{"name":"Science and Technology Innovation 2035 Major Projects, Ningbo, China","award":["2024Z097"],"award-info":[{"award-number":["2024Z097"]}]},{"DOI":"10.13039\/501100007928","name":"Ningbo Science & Technology Bureau","doi-asserted-by":"crossref","award":["2022-DST-001"],"award-info":[{"award-number":["2022-DST-001"]}],"id":[{"id":"10.13039\/501100007928","id-type":"DOI","asserted-by":"crossref"}]},{"award":["2022-DST-001"],"award-info":[{"award-number":["2022-DST-001"]}],"id":[{"id":"https:\/\/ror.org\/00gskyj95","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>Water-lubricated seal interfaces are particularly vulnerable to fluid-film instability, which accelerates interfacial friction and wear and compromises the reliability and service life of underwater equipment. Here, a novel graphite-microcrystalline diamond (Graphite-MCD) soft\u2013hard seal-face tribopair was proposed and systematically benchmarked against SiC-SiC and Graphite-SiC tribopairs under high-pressure water lubrication. Their sealing capacity, friction and wear behavior, and interfacial evolution were evaluated. The polished Graphite-MCD pair achieved the highest limiting PcV (90.73 MPa\u00b7m\u00b7s\u22121) and the lowest wear rate, markedly outperforming the SiC-SiC and Graphite-SiC pairs. Multiscale interfacial characterization showed that the SiC-SiC pair failed primarily through adhesive instability after breakdown of the water film. Although the Graphite-SiC pair reduced interfacial shear resistance, sliding generated a continuous triboreaction layer accompanied by third-body wear. In contrast, the Graphite-MCD pair preserved interfacial structural integrity and suppressed the formation of an unstable continuous reaction layer and abundant abrasive debris. This behavior enabled a synergistic combination of a low-shear lubricating interface and a stiff load-bearing counterface. These results demonstrate that improving the limiting PcV of mechanical seals cannot be achieved by reducing the friction coefficient alone; rather, it requires simultaneous control of lubricity and interfacial stability. The findings provide a mechanistic basis for designing soft\u2013hard tribopairs for high-pressure, water-lubricated mechanical seals.<\/jats:p>","DOI":"10.3390\/ma19183810","type":"journal-article","created":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T08:10:22Z","timestamp":1788855022000},"page":"3810","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Limiting PcV and Tribological Performance of Mechanical Seals with Hard\u2013Hard and Soft\u2013Hard Tribopairs Under Water Lubrication"],"prefix":"10.3390","volume":"19","author":[{"given":"Xiaoming","family":"Ren","sequence":"first","affiliation":[{"name":"School of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, China"},{"name":"State Key Laboratory of Advanced Marine Materials, Zhejiang Key Laboratory of Extreme-Environmental Material Surfaces and Interfaces, Ningbo Institute of Materials Technology and Engineering, Chinese 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Relat. Mater."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"130204","DOI":"10.1016\/j.surfcoat.2023.130204","article-title":"Tribological behavior of diamond coated reaction-bonded silicon carbide under dry and seawater environment","volume":"476","author":"Ramasubramanian","year":"2024","journal-title":"Surf. Coat. Technol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"96","DOI":"10.1016\/j.triboint.2015.05.022","article-title":"Experimental and numerical study of the lubrication regimes of a liquid mechanical seal","volume":"92","author":"Ayadi","year":"2015","journal-title":"Tribol. Int."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"111039","DOI":"10.1016\/j.diamond.2024.111039","article-title":"Superior tribological and sealing performance of micro-crystalline diamond coated silicon carbide seals under dry friction and high load","volume":"144","author":"Xia","year":"2024","journal-title":"Diam. Relat. Mater."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"148","DOI":"10.1038\/s41598-017-00238-0","article-title":"Unexpected friction behaviours due to capillary and adhesion effects","volume":"7","author":"Guo","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"697","DOI":"10.1007\/s40544-020-0364-5","article-title":"Friction and wear behavior of different seal materials under water-lubricated conditions","volume":"9","author":"Zhao","year":"2021","journal-title":"Friction"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Guo, D., Cai, N., Wu, G., Xie, F., Tan, S., Jiang, N., and Li, H. (2020). Improving pressure\u2013velocity limit of mechanical seal with polycrystalline diamond coating. Appl. Sci., 10.","DOI":"10.3390\/app10176090"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"169","DOI":"10.1016\/S0257-8972(98)00481-2","article-title":"Diamond coatings applied to mechanical face seals","volume":"105","author":"Hollman","year":"1998","journal-title":"Surf. Coat. Technol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"134","DOI":"10.1007\/s11249-025-02064-2","article-title":"Sliding friction of hard sliders on rubber: Theory and experiment","volume":"73","author":"Xu","year":"2025","journal-title":"Tribol. Lett."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1203","DOI":"10.1016\/j.jmst.2016.06.013","article-title":"Friction characteristics of impregnated and non-impregnated graphite against cemented carbide under water lubrication","volume":"33","author":"Zhang","year":"2017","journal-title":"J. Mater. Sci. Technol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"107715","DOI":"10.1016\/j.triboint.2022.107715","article-title":"Friction and wear performances of impregnated graphite in ring-on-ring tribological test","volume":"174","author":"Zhao","year":"2022","journal-title":"Tribol. Int."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"205665","DOI":"10.1016\/j.wear.2024.205665","article-title":"Friction reduction and anti-wear mechanisms of surface-textured graphite under water lubrication","volume":"562\u2013563","author":"Zheng","year":"2025","journal-title":"Wear"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1141","DOI":"10.1016\/j.wear.2009.03.018","article-title":"Formation of transfer layer and its effect on friction and wear of carbon\u2013graphite face seal under dry, water and steam environments","volume":"266","author":"Hirani","year":"2009","journal-title":"Wear"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"17475","DOI":"10.1016\/j.ceramint.2024.02.235","article-title":"Tribological properties of reaction-formed graphite\/SiC composites under water-lubricated conditions","volume":"50","author":"Su","year":"2024","journal-title":"Ceram. Int."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"110943","DOI":"10.1016\/j.triboint.2025.110943","article-title":"Polishability and tribological performances of various CVD diamond coatings deposited on SiC ceramics seal ring","volume":"212","author":"Zhu","year":"2025","journal-title":"Tribol. Int."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"178","DOI":"10.1016\/j.wear.2017.01.058","article-title":"Multilayered diamond mechanical seal rings under biodiesel lubrication and the full sealing conditions of pressurized water","volume":"384\u2013385","author":"Shabani","year":"2017","journal-title":"Wear"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"325","DOI":"10.1016\/j.wear.2010.10.059","article-title":"Development of ultrananocrystalline diamond (UNCD) coatings for multipurpose mechanical pump seals","volume":"270","author":"Kovalchenko","year":"2011","journal-title":"Wear"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Du, Y., Xie, F., Wang, J., Xu, B., Chen, H., Yan, B., Wu, Y., Huang, W., and Li, H. (2023). Dry Friction Properties of Diamond-Coated Silicon Carbide. Materials, 16.","DOI":"10.3390\/ma16103640"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Liu, S., Zhang, B., Cai, L., Wang, W., Liang, T., and Lei, M. (2024). High-Temperature and High-Pressure Tribological Properties of Siliconized Graphite for Water-Lubricated Thrust Bearing Application in Main Coolant Pump. Lubricants, 12.","DOI":"10.3390\/lubricants12050159"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Di, Z., Wang, Z., Zhang, X., Si, J., Song, J., Fan, H., Su, Y., Hu, L., and Zhang, Y. (2024). Tribological properties of Al2O3\/graphite-Al2O3 laminated composites under water lubrication conditions. Lubricants, 12.","DOI":"10.3390\/lubricants12030081"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"110792","DOI":"10.1016\/j.anucene.2024.110792","article-title":"Tribological behaviors and wettability evolution of phenolic resin-impregnated graphite materials under water immersion condition","volume":"208","author":"Xu","year":"2024","journal-title":"Ann. Nucl. Energy"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"100414","DOI":"10.1016\/j.cartre.2024.100414","article-title":"Nanoscale friction and wear of graphite surface in ambient and underwater conditions","volume":"17","author":"Soni","year":"2024","journal-title":"Carbon Trends"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"110069","DOI":"10.1016\/j.commatsci.2020.110069","article-title":"Behaviors of carbon atoms induced by friction in mechanical polishing of diamond","volume":"186","author":"Liu","year":"2021","journal-title":"Comput. Mater. Sci."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1016\/j.ijrmhm.2005.11.012","article-title":"XRD stress analysis of CVD diamond coatings on SiC substrates","volume":"25","author":"Chowdhury","year":"2007","journal-title":"Int. J. Refract. Met. Hard Mater."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1016\/j.diamond.2008.08.016","article-title":"HFCVD nanocrystalline diamond coatings for tribo-applications in the presence of water","volume":"18","author":"Abreu","year":"2009","journal-title":"Diam. Relat. Mater."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"686","DOI":"10.1007\/s40544-019-0358-3","article-title":"Influence of a carbon-based tribofilm induced by the friction temperature on the tribological properties of impregnated graphite sliding against a cemented carbide","volume":"9","author":"Zhao","year":"2021","journal-title":"Friction"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"181","DOI":"10.1007\/s40544-018-0219-5","article-title":"Experimental study on the tribo-chemical smoothening process between self-mated silicon carbide in a water-lubricated surface-contact reciprocating test","volume":"7","author":"Jin","year":"2019","journal-title":"Friction"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"107071","DOI":"10.1016\/j.ijrmhm.2025.107071","article-title":"The influence of diamond grain sizes on the tribological performance and ultimate loading capacity of polycrystalline diamond self-mated friction pairs under water lubricated condition","volume":"128","author":"Xu","year":"2025","journal-title":"Int. J. Refract. Met. Hard Mater."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"2728","DOI":"10.1021\/acs.jpcc.1c07668","article-title":"Three tribolayers self-generated from SiC individually work for reducing friction in different contact pressures","volume":"126","author":"Ootani","year":"2022","journal-title":"J. Phys. Chem. C"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"205674","DOI":"10.1016\/j.wear.2024.205674","article-title":"Wear mechanism and three-phase synergistic effect of self-mated SiC\/Si\/graphite composites in unlubricated sliding","volume":"564\u2013565","author":"Du","year":"2025","journal-title":"Wear"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"112242","DOI":"10.1016\/j.diamond.2025.112242","article-title":"Tribology of self-mated siliconized graphite under high pv factors in high-temperature and high-pressure water","volume":"154","author":"Liu","year":"2025","journal-title":"Diam. Relat. Mater."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"110579","DOI":"10.1016\/j.triboint.2025.110579","article-title":"Continuous formation and removal mechanism of tribolayer on silicon carbide under water lubricated conditions: A ReaxFF reactive molecular dynamics study","volume":"206","author":"Kawaura","year":"2025","journal-title":"Tribol. Int."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"14957","DOI":"10.1021\/acs.jpcc.1c02765","article-title":"Selective wear behaviors of a water-lubricating SiC surface under rotating-contact conditions revealed by large-scale reactive molecular dynamics simulations","volume":"125","author":"Wang","year":"2021","journal-title":"J. Phys. Chem. C"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"119713","DOI":"10.1016\/j.carbon.2024.119713","article-title":"Environment-dependent tribochemical reaction and wear mechanisms of diamond-like carbon: A reactive molecular dynamics study","volume":"231","author":"Zhang","year":"2025","journal-title":"Carbon"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1016\/j.triboint.2015.05.029","article-title":"Study of the fluid film vaporization in the interface of a mechanical face seal","volume":"92","author":"Migout","year":"2015","journal-title":"Tribol. 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