{"title":"ZDDP Tribofilm Formation and Removal","authors":"Mao Ueda, Hugh Spikes","doi":"10.1007/s11249-024-01915-8","DOIUrl":null,"url":null,"abstract":"<div><p>While ZDDP tribofilm formation has been widely studied, the mechanism of ZDDP tribofilm removal during rubbing is still unclear. The study employs a ball on disc tribometer to monitor ZDDP tribofilm development in rolling-sliding, mixed lubrication conditions. It is found that when ZDDP tribofilms are formed very rapidly, as is the case with short alkyl chain, secondary ZDDPs, a large proportion of the initially-formed tribofilm is suddenly lost during rubbing. By contrast, the tribofilms that form more slowly from primary ZDDPs and longer chain secondaries are not partially lost during rubbing. XPS analysis showed that a rapidly-formed tribofilm before its partial removal has a very small Zn/O ratio, and a high BO/NBO. This suggests that such tribofilm contains a significant proportion of ultraphosphate, which is likely to have a relatively weak structure due to lack of stabilising cations. This may result in the tribofilm being partially removed when it reaches a certain thickness. By comparison, the remaining tribofilm, and also tribofilms that form slowly, have high Zn/O and low BO/NBO. This suggests that they consist of short chain polyphosphates and are thus stronger and more durable.</p><h3>Graphical Abstract</h3>\n<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":null,"pages":null},"PeriodicalIF":2.9000,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-024-01915-8.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Tribology Letters","FirstCategoryId":"5","ListUrlMain":"https://link.springer.com/article/10.1007/s11249-024-01915-8","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
While ZDDP tribofilm formation has been widely studied, the mechanism of ZDDP tribofilm removal during rubbing is still unclear. The study employs a ball on disc tribometer to monitor ZDDP tribofilm development in rolling-sliding, mixed lubrication conditions. It is found that when ZDDP tribofilms are formed very rapidly, as is the case with short alkyl chain, secondary ZDDPs, a large proportion of the initially-formed tribofilm is suddenly lost during rubbing. By contrast, the tribofilms that form more slowly from primary ZDDPs and longer chain secondaries are not partially lost during rubbing. XPS analysis showed that a rapidly-formed tribofilm before its partial removal has a very small Zn/O ratio, and a high BO/NBO. This suggests that such tribofilm contains a significant proportion of ultraphosphate, which is likely to have a relatively weak structure due to lack of stabilising cations. This may result in the tribofilm being partially removed when it reaches a certain thickness. By comparison, the remaining tribofilm, and also tribofilms that form slowly, have high Zn/O and low BO/NBO. This suggests that they consist of short chain polyphosphates and are thus stronger and more durable.
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.