Priyanka Agarwal, Suheel K. Porwal, Jyoti Porwal, Raj K. Singh, Naveen Singhal
{"title":"Chemically functionalized graphene oxide with N-phenyl-p-phenylenediamine as efficient tribo- and rheological modifier for lubricating oil","authors":"Priyanka Agarwal, Suheel K. Porwal, Jyoti Porwal, Raj K. Singh, Naveen Singhal","doi":"10.1002/ls.1636","DOIUrl":"10.1002/ls.1636","url":null,"abstract":"<p>Nanoadditive with multifunctional properties holds commercial importance in the lubricant industry. Herein, GO-<i>N</i>-PPDA was synthesised as nanoadditive by functionalizing graphene oxide (GO) using <i>N</i>-phenyl-<i>p</i>-phenylenediamine and characterised by Fourier transform infrared spectroscopy, X-ray diffraction analysis, thermogravimetric analysis, scanning electron microscopy and transmission electron microscopy analysis. The antioxidant behaviour of GO-<i>N</i>-PPDA was analysed by 2,2-diphenyl-1-picryl-hydrazyl-hydrate. The nanoparticles dispersed mineral base oil (N-250) in 0.2%, 0.4%, 0.6% (w/v) concentrations were evaluated for tribological, rheological and thermophysical analysis by ASTM methods. The flow behaviour of the nanolubricant shows shear thickening behaviour with an increase in shear rate. In contrast, tribological results indicate a significant reduction in wear scar diameter and coefficient of friction to the base oil. Furthermore, GO-<i>N</i>-PPDA shows improved thermophysical properties compared with the mineral base oil. Thus, GO-<i>N</i>-PPDA shows multifunctional behaviour in terms of viscosity index, pour point, antioxidant activity, rheology and tribological properties.</p>","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2022-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43456184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Preparation of graphene-loading copper nanoparticles by freeze drying and its tribological properties","authors":"Runling Peng, Wei Wang, Peng Wang, Jinyue Liu, Shijiao Liu, Haonan Zhai, Junde Guo","doi":"10.1002/ls.1638","DOIUrl":"10.1002/ls.1638","url":null,"abstract":"<p>To reduce the agglomeration of graphene and improve the synergistic friction-reducing and anti-wear action of graphene loading copper, one-step preparation of reduced graphene oxide/copper(RGO/Cu) nanoparticles by freeze-drying method was used, the influence of process parameters on particles size of RGO/Cu is studied by orthogonal experiments. The microstructures of RGO/Cu nanoparticles are characterized by SEM and AFM, and the tribological properties of RGO/Cu nanoparticles are studied on a tribometer. The results show that the purity of RGO/Cu nanoparticles prepared by freeze-drying was higher, and the copper nanoparticles 100–200 nm are uniformly attached to the graphene surface. It was found that RGO/Cu nanoparticles have better friction reduction and anti-wear properties than graphene mono-agent as lubricant additive. The synergistic anti-friction and anti-wear performance are better at the addition of 0.10 wt% for RGO/Cu nanoparticles. Compared with the base oil, the friction coefficient decreases by 23.1%, and the width of wear scar decreases by 62.5%.</p>","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2022-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42437791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Javier Lara-Romero, Ricardo Rangel, Julián López-Tinoco, Jesús Antonio Carlos-Cornelio, Alejandro Toro-Betancur, Fernando Chiñas-Castillo, Gabriel Alonso-Nuñez, Sergio Jiménez-Sandoval
{"title":"Tribological performance of ammonium thiomolybdate as water-soluble lubricant additive for steel-steel contacts","authors":"Javier Lara-Romero, Ricardo Rangel, Julián López-Tinoco, Jesús Antonio Carlos-Cornelio, Alejandro Toro-Betancur, Fernando Chiñas-Castillo, Gabriel Alonso-Nuñez, Sergio Jiménez-Sandoval","doi":"10.1002/ls.1637","DOIUrl":"10.1002/ls.1637","url":null,"abstract":"<p>The friction and wear reducing properties of ammonium thiomolybdate as a water-soluble lubricant additive were evaluated using a pin-on-disck tribometer on a steel-steel contact. The tribological performance of aqueous solutions of thiomolybdate prepared at concentrations between 0.1 and 0.3 wt% Mo were evaluated at the same load (10 N), entrainment speed, sliding distance and temperature. Although there is a reduction of friction and wear compared with pure water, a significant difference is observed, depending on the additive concentration. SEM/EDAX and Raman spectroscopy analyses of the wear tracks of specimens tested at concentrations below 0.3 wt% Mo reveal the formation of FeS which is responsible for gradually reducing the coefficient of friction from values between 0.30 and 0.5 down to ~0.11. At 0.3 wt% Mo, the analyses indicated the formation of a MoS<sub>2</sub> which keeps the coefficient of friction in ~0.05, the lowest recorded value.</p>","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2022-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48512353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Impact of partial surface waviness on the tribological performance of hydrodynamic journal bearing","authors":"Arun Bangotra, Sanjay Sharma","doi":"10.1002/ls.1633","DOIUrl":"10.1002/ls.1633","url":null,"abstract":"<p>In this paper, the static performance analysis of journal bearing having full and partial surface waviness has been presented. The surface waviness is to be considered in the full, first half, second half, and pressure-increasing and decreasing regions of the bearing for analysis. The effect of surface waviness is considered by modifying the lubricant flow governing Reynolds equation with the film thickness equation and it is solved with the finite element method to get performance parameters like bearing load capacity, friction coefficient, and so forth operating under eccentricity ratios range of 0.2–0.8. The waviness geometrical parameters like waviness numbers and amplitudes are also considered in circumferential, axial, and both directions in the selected regions. The maximum performance has been found for waviness in the full and pressure-increasing region in the circumferential direction at a high eccentricity ratio.</p>","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2022-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44003550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of copper nanoparticle concentration on tribological performances of cylinder liner piston ring","authors":"Huabing Yin, Xuecheng Zhang, Zhiwei Guo, Zhongzhi Liu, Xiang Rao, Chengqing Yuan","doi":"10.1002/ls.1634","DOIUrl":"10.1002/ls.1634","url":null,"abstract":"<p>The performance of cylinder liner piston ring (CLPR) that worked under harsh conditions significantly affected the reliability of diesel engines. Nano-copper lubricant additives have recently been introduced due to their good anti-wear properties. This study aims to gain insights into the interactions between concentrations of nano-copper lubricant additives and the tribological performance of CLPR. Tests are performed on a reciprocating sliding test rig under different operating conditions, and the tribological performances are characterized by the friction coefficient, wear mass losses, and morphologies of worn surface. The experimental results indicated that the optimal concentration of nano-copper additives is 2 wt%. Additionally, deposition of the Cu nanoparticles on the worn surface during the friction process facilitates the formation of the mending layer. These findings would aid to provide a technical reference for the application of nano-copper additives in diesel engines.</p>","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41485713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ehsan Fatourehchi, Hamed Shahmohamadi, Ramin Rahmani, Homer Rahnejat, Mark Johnson, Ian Wilson
{"title":"Tribology of dust-stop seals of mixing machines","authors":"Ehsan Fatourehchi, Hamed Shahmohamadi, Ramin Rahmani, Homer Rahnejat, Mark Johnson, Ian Wilson","doi":"10.1002/ls.1632","DOIUrl":"10.1002/ls.1632","url":null,"abstract":"<p>Dust stop seals are widely used in powder and rubber mixing industries. Design of the sealing system requires a continuous supply of pressurised lubricant, which is not recycled because of the risk of contamination. There is also the potential of large volume leakage of oil due to poor sealing, increasing operational costs and necessitating remedial measures to avoid environmental protection. Furthermore, the seal faces are prone to failure in relatively short periods of time due to reduced gap and lubricant leakage. The paper presents an analytical method and numerical predictions based on Reynolds equation under combined hydrodynamic and hydrostatic conditions with the entrant lubricant through hydraulically loaded feedholes. The validity of these methods is ascertained through comparison with a more complex but time-consuming solution of Navier–Stokes equations. The numerical predictions allow for determining the prevailing tribological contact conditions and assessing its suitability for evaluating the sealing performance of mixing machinery.</p>","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ls.1632","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44436223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Tribological performance study of oil-soluble ILs as lubricant additives by the four-ball method","authors":"Zhaozhao Yang, Yijing Liang, Qing Huang, Xingwei Wang, Chunyu Zhou, Ruozheng Wang, Xiaoyan Yan, Bo Yu, Qiangliang Yu, Meirong Cai, Feng Zhou","doi":"10.1002/ls.1631","DOIUrl":"10.1002/ls.1631","url":null,"abstract":"Four oil‐soluble ionic liquids (ILs) with different structures were synthesised: N88816‐Doss (N/S), P88816‐Doss (P/S), N88816 phosphate (N/P) and P88816 phosphate (P/P). The effects of the four ILs synthesised with conventional lubricating additives isobutylene sulfide (T321), zinc dialkyl dithiophosphate (ZDDP) and tricresyl phosphate (T306) as PAO10 additives on the physicochemical properties of the prepared oil samples were systematically investigated at the same dosing rates. The antifriction and antiwear properties and extreme pressure performance of oil samples prepared by four ILs and three conventional additives were investigated by a four‐ball friction and a wear testing machine. The results showed that P/S improved the thermal stability of PAO10. The addition of N/S significantly improved the tribological performance of PAO10 at room temperature and under heavy loading. The coefficient of friction was reduced by 90%, the wear spot diameter is decreased by 28%, the last non‐seizure load PB is doubled, and the resistance to sintering did not improve.","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2022-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48576477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Kinetics study of cold rolling lubricant degradation through advanced instrumental techniques","authors":"Subho Chakraborty, Suvendu Sekhar Giri, Ashwin Pandit, Amarnath Bhagat, Ajay Kumar Jha","doi":"10.1002/ls.1630","DOIUrl":"10.1002/ls.1630","url":null,"abstract":"<p>Research was focused on understanding the degradation kinetics of cold rolling oil used in the rolling mill at Tata Steel. Aged rolling oil leads to various surface defects. Ageing phenomenon is influenced through thermo-mechanical behaviour, oxidation, hydrolysis and presence of iron fines. Ageing of cold rolling oil in presence of iron fines was systematically performed at various temperature followed by thermo-mechanical wear tests. With variation in intensity of ageing, change in physico-chemical parameters and fatty acid distribution (FAD) within triglycerides could be observed. The impact of the controlled ageing on performance parameters like lubrication, evaporation kinetics and oxidative stability were also studied. Thermo-oxidative ageing depletes antioxidant concentration within the rolling oil resulting in rapid oxidation of unsaturated fats. This leads to rapid build-up of high molecular weight ingredients resulting in formation of fatty acid soaps or scum. The resultant scum negatively impacts the boundary lubrication and evaporation kinetics of rolling oil.</p>","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2022-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46445845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Flow and slip process of Santotrac 50-based lubricant under high shear by molecular dynamic simulation","authors":"Xin Zhao, Chao Wei, Zhenxin Yin, Wenjie Ma","doi":"10.1002/ls.1629","DOIUrl":"10.1002/ls.1629","url":null,"abstract":"<p>We investigate flow and slip behaviour of Santotrac 50 molecules under high shear in Couette cell by means of Molecular Dynamic simulation to understand reduced friction force. Molecular chain stretches and oriented to shear direction, and move. Slip starts on metal surface at 2 × 10<sup>8</sup> s<sup>−1</sup>, and increases with shear rate. Slip length keeps scale at nanometre. Molecular conformation and occurrence of slip both indicate a reduced shear stress. Furthermore, when changing wettability, slip length increases in power law and thus decreases shear stress greatly. Occurrence of low-density region near surface can explain slip. And thus, we extended apparent slip model, which divided lubricant into liquid layers with different viscosities, to elucidate the relationship between molecule distribution inner layer and slip on surface influenced by shear velocity and wettability. Above all, our research sheds light on flow and slip behaviour of complex fluid and can be applied in improving lubrication property.</p>","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2022-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49291319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of thermal oxidation on structural and tribological properties of MoS2 films","authors":"Hikmet Çiçek, Özkan Gözübüyük, İhsan Efeoğlu","doi":"10.1002/ls.1628","DOIUrl":"10.1002/ls.1628","url":null,"abstract":"<p>The aim of this study is to investigate the structural, mechanical and tribological behaviours of thermally oxidized MoS<sub>2</sub> films. MoS<sub>2</sub> coatings were deposited on D2 tool steel substrates using the closed field unbalanced magnetron sputtering method (CFUBMS). The thermal oxidation process was carried out at four different temperatures. Tribological properties were determined by pin-on-disc wear tests in the atmospheric environment. It was determined that thermal oxidation temperatures affected the chemical composition of MoS<sub>2</sub> films, but did not cause any change in film thickness. The wear rates of the samples differed depending on the oxidation temperature and the applied load. The lowest wear rate was determined as 1.97 × 10<sup>−8</sup> mm<sup>3</sup>/Nm in the oxidized film at 350°C. In addition, the highest hardness value was obtained as 655 HV in the film oxidized at 400°C, and the lowest coefficient of friction was obtained as 0.01 in the film oxidized at 350°C.</p>","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2022-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43928433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}