Effect of Nickel Acetyl Acetonate as Lubricant Additive in Base Oils with Different Molecular Structure on In-Situ Formation and Tribomechanism of Carbon-Based Tribofilms of Steel-Steel Sliding Pair
{"title":"Effect of Nickel Acetyl Acetonate as Lubricant Additive in Base Oils with Different Molecular Structure on In-Situ Formation and Tribomechanism of Carbon-Based Tribofilms of Steel-Steel Sliding Pair","authors":"Feng Peng, Shuguang Fan, Ningning Song, Chuanping Gao, Shengmao Zhang, Yujuan Zhang","doi":"10.1007/s11249-024-01859-z","DOIUrl":null,"url":null,"abstract":"<div><p>Nickel acetyl acetonate (Ni(acac)<sub>2</sub>), a metal-organic compound, was directly dispersed in base oils alkylated naphthalene (AN-5), diisooctyl sebacate (DIOS), poly-α-olefin (PAO6), and mineral oil (liquid hydrocarbon mixtures:150 N) in the presence of commercial dispersant RF1151 (monoallyl poly(isobutylene succinimide). The tribological properties of the lubricants were tested with a four-ball friction and wear tester. The friction-induced in-situ formation of carbon films on rubbed steel surfaces under the catalysis of Ni(acac)<sub>2</sub> was investigated, and the as-formed carbon films were characterized by scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The results show that Ni(acac)<sub>2</sub> added in the base oils can decompose to form metallic nickel to form nickel layer on the rubbed metal sub-surfaces and catalyze the degradation of the base oil molecules adsorbed to form carbon-based tribofilms. The carbon film formed from AN-5 with aromatic ring structure has a high degree of graphitization and the best friction-reducing and antiwear abilities, and those formed from PAO6 and 150 N with linear structure have a low degree of graphitization as well as good tribological properties. Under the lubrication of DIOS with Ni(acac)<sub>2</sub>, however, there is no carbon film formation while the tribological properties of the lubricant are relatively poor, due to the absence of the catalytic metallic nickel and nickel oxide layer on the rubbed metal sub-surface. Thanks to the catalytic effect of metallic nickel released from Ni(acac)<sub>2</sub> for the degradation of various base oils with different molecular structure, the present approach could provide a rational pathway to tune the in-situ formation of carbon-based tribofilm on rubbed steel surfaces so as to effectively reduce the friction and wear of steel-steel sliding pair.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":null,"pages":null},"PeriodicalIF":2.9000,"publicationDate":"2024-04-25","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/s11249-024-01859-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}
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Abstract
Nickel acetyl acetonate (Ni(acac)2), a metal-organic compound, was directly dispersed in base oils alkylated naphthalene (AN-5), diisooctyl sebacate (DIOS), poly-α-olefin (PAO6), and mineral oil (liquid hydrocarbon mixtures:150 N) in the presence of commercial dispersant RF1151 (monoallyl poly(isobutylene succinimide). The tribological properties of the lubricants were tested with a four-ball friction and wear tester. The friction-induced in-situ formation of carbon films on rubbed steel surfaces under the catalysis of Ni(acac)2 was investigated, and the as-formed carbon films were characterized by scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The results show that Ni(acac)2 added in the base oils can decompose to form metallic nickel to form nickel layer on the rubbed metal sub-surfaces and catalyze the degradation of the base oil molecules adsorbed to form carbon-based tribofilms. The carbon film formed from AN-5 with aromatic ring structure has a high degree of graphitization and the best friction-reducing and antiwear abilities, and those formed from PAO6 and 150 N with linear structure have a low degree of graphitization as well as good tribological properties. Under the lubrication of DIOS with Ni(acac)2, however, there is no carbon film formation while the tribological properties of the lubricant are relatively poor, due to the absence of the catalytic metallic nickel and nickel oxide layer on the rubbed metal sub-surface. Thanks to the catalytic effect of metallic nickel released from Ni(acac)2 for the degradation of various base oils with different molecular structure, the present approach could provide a rational pathway to tune the in-situ formation of carbon-based tribofilm on rubbed steel surfaces so as to effectively reduce the friction and wear of steel-steel sliding pair.
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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