{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,9]],"date-time":"2026-03-09T08:51:40Z","timestamp":1773046300563,"version":"3.50.1"},"reference-count":31,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2017,8,17]],"date-time":"2017-08-17T00:00:00Z","timestamp":1502928000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Lubricants"],"abstract":"<jats:p>The relationship between the film generation and the coefficient of friction in grease lubricated contacts was investigated. Ball-on-disc tests were performed under different operating conditions: entrainment speed, lubricant temperature and surface roughness. The tests were performed with fully formulated greases and their base oils. The greases were formulated with different thickener types and also different base oils natures and viscosities. Film thickness measurements were performed in ball-on-glass disc tests, and Stribeck curves were measured in ball-on-steel disc tests with discs of different roughness. The role of the thickener and the base oil nature\/viscosity on the film thickness and coefficient of friction was addressed and the greases\u2019 performance was compared based on their formulation.<\/jats:p>","DOI":"10.3390\/lubricants5030034","type":"journal-article","created":{"date-parts":[[2017,8,21]],"date-time":"2017-08-21T04:12:17Z","timestamp":1503288737000},"page":"34","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":40,"title":["Film Thickness and Friction Relationship in Grease Lubricated Rough Contacts"],"prefix":"10.3390","volume":"5","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0549-3399","authenticated-orcid":false,"given":"David","family":"Gon\u00e7alves","sequence":"first","affiliation":[{"name":"Instituto de Ci\u00eancia e Inova\u00e7\u00e3o em Engenharia Mec\u00e2nica e Engenharia Industrial, Universidade do Porto, Campus FEUP, Rua Dr. Roberto Frias 400, 4200-465 Porto, Portugal"}]},{"given":"Ant\u00f3nio","family":"Vieira","sequence":"additional","affiliation":[{"name":"Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias s\/n, 4200-465 Porto, Portugal"}]},{"given":"Ant\u00f3nio","family":"Carneiro","sequence":"additional","affiliation":[{"name":"Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias s\/n, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7400-7449","authenticated-orcid":false,"given":"Armando","family":"Campos","sequence":"additional","affiliation":[{"name":"Instituto Superior de Engenharia do Polit\u00e9cnico do Porto, Rua Dr. Ant\u00f3nio Bernardino de Almeida 431, 4200-072 Porto, Portugal"}]},{"given":"Jorge","family":"Seabra","sequence":"additional","affiliation":[{"name":"Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias s\/n, 4200-465 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2017,8,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"179","DOI":"10.1016\/0301-679X(91)90024-4","article-title":"Video recordings of an EHD point contact lubricated with grease","volume":"24","author":"Isaksson","year":"1991","journal-title":"Tribol. 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