{"title":"In Situ Analysis of Friction and Wear Behavior of Polymeric Composite Coatings for Hydrogen Valve Applications","authors":"Danavath Balu, Piyush Chandra Verma, Pavan Kumar Penumakala, Prabakaran Saravanan","doi":"10.1007/s11249-026-02118-z","DOIUrl":null,"url":null,"abstract":"<div><p>This study focuses on the development of protective polymer coatings to reduce hydrogen diffusion (HD) in steel valve components used in hydrogen refueling stations (HRSs). Two low hydrogen permeability (HP) polymers, polytetrafluoroethylene (PTFE) and polyurethane (PU), were selected and deposited onto 316 stainless steel disks using a spray-coating technique. Tribological tests were conducted in atmosphere air, nitrogen (N<sub>2</sub>), and hydrogen (H<sub>2</sub>) at 0.2 MPa using a custom-built multi-environment pin-on-disk tribometer, with each test repeated twice to ensure reliability. PTFE consistently demonstrated superior tribological performance compared to PU across all environments. The coefficient of friction (CoF) for PTFE was lower by approximately 33% in atmosphere air, 33% in N<sub>2</sub>, and 57% in H<sub>2</sub>. Similarly, the specific wear rate (SWR) of PTFE was reduced by about 30% in atmosphere air, 16% in N<sub>2</sub>, and 53% in H<sub>2</sub> relative to PU, confirming PTFE’s excellent suitability for H<sub>2</sub>-exposed conditions. FESEM analysis showed that PTFE forms a fibrous coating structure, while PU exhibits denser morphology, with average coating thicknesses of 34 μm and 36 μm, respectively. CHNS analysis revealed major distinction in H<sub>2</sub> absorption. PU absorbed 5.61-wt% H<sub>2</sub>, whereas PTFE absorbed only 0.87 wt%. The lower H<sub>2</sub> absorption in PTFE correlates strongly with its improved frictional stability, reduced wear, and enhanced hydrogen barrier properties. Additional chemical characterizations were performed to understand H<sub>2</sub> interactions and their influence on the observed tribological trends. Overall, PTFE exhibited excellent frictional behavior, wear resistance, and HP barrier capability, establishing it as a promising candidate for protecting steel components in HRSs.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 1","pages":""},"PeriodicalIF":3.3000,"publicationDate":"2026-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Tribology Letters","FirstCategoryId":"5","ListUrlMain":"https://link.springer.com/article/10.1007/s11249-026-02118-z","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}
引用次数: 0
Abstract
This study focuses on the development of protective polymer coatings to reduce hydrogen diffusion (HD) in steel valve components used in hydrogen refueling stations (HRSs). Two low hydrogen permeability (HP) polymers, polytetrafluoroethylene (PTFE) and polyurethane (PU), were selected and deposited onto 316 stainless steel disks using a spray-coating technique. Tribological tests were conducted in atmosphere air, nitrogen (N2), and hydrogen (H2) at 0.2 MPa using a custom-built multi-environment pin-on-disk tribometer, with each test repeated twice to ensure reliability. PTFE consistently demonstrated superior tribological performance compared to PU across all environments. The coefficient of friction (CoF) for PTFE was lower by approximately 33% in atmosphere air, 33% in N2, and 57% in H2. Similarly, the specific wear rate (SWR) of PTFE was reduced by about 30% in atmosphere air, 16% in N2, and 53% in H2 relative to PU, confirming PTFE’s excellent suitability for H2-exposed conditions. FESEM analysis showed that PTFE forms a fibrous coating structure, while PU exhibits denser morphology, with average coating thicknesses of 34 μm and 36 μm, respectively. CHNS analysis revealed major distinction in H2 absorption. PU absorbed 5.61-wt% H2, whereas PTFE absorbed only 0.87 wt%. The lower H2 absorption in PTFE correlates strongly with its improved frictional stability, reduced wear, and enhanced hydrogen barrier properties. Additional chemical characterizations were performed to understand H2 interactions and their influence on the observed tribological trends. Overall, PTFE exhibited excellent frictional behavior, wear resistance, and HP barrier capability, establishing it as a promising candidate for protecting steel components in HRSs.
期刊介绍：
Tribology Letters is devoted to the development of the science of tribology and its applications, particularly focusing on publishing high-quality papers at the forefront of tribological science and that address the fundamentals of friction, lubrication, wear, or adhesion. The journal facilitates communication and exchange of seminal ideas among thousands of practitioners who are engaged worldwide in the pursuit of tribology-based science and technology.
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