Tribological behavior of thermal- and pH-sensitive microgels under steel/CoCrMo alloy contacts

• Published in: Friction Vol. 11; no. 4; pp. 602 - 616
• Main Authors: Sun, Kequn, Hu, Yuanhua, Dong, Yinghui, Yao, Lulu, Song, Ruhong, Xu, Yufu
• Format: Journal Article
• Language: English
• Published: Beijing Tsinghua University Press 01.04.2023; Springer Nature B.V; Institute of Tribology,School of Mechanical Engineering,Hefei University of Technology,Hefei 230009,China%School of Chemistry and Chemical Engineering,Hefei University of Technology,Hefei 230009,China
• Subjects: Acids; Additives; Aqueous solutions; Biocompatibility; Cobalt base alloys; Coefficient of friction; Corrosion and Coatings; Corrosion potential; Emulsion polymerization; Engineering; Experiments; Fourier transforms; Friction; Lubricants; Lubricants & lubrication; Lubrication; Mechanical Engineering; Mechanical properties; Microgels; Nanoparticles; Nanotechnology; Physical Chemistry; Polyacrylic acid; Polyisopropyl acrylamide; Research Article; Stainless steel; Stainless steels; Surfaces and Interfaces; Thin Films; Tribology; Wear; poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAM-co-PAA); pH-sensitive; microgel; thermal-sensitive; aqueous lubrication
• ISSN: 2223-7690; 2223-7704
• DOI: 10.1007/s40544-022-0623-8

The tribological behavior of 316L stainless steel/CoCrMo alloy contacts under aqueous lubrication was investigated in this work. Three types of microgels including poly(N-isopropylacrylamide) (PNIPAM), polyacrylic acid (PAA), and poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAM-co-PAA) were prepared and used as lubricant additives in aqueous solutions. Tribological tests were conducted using a ball-on-disk reciprocating tribometer, over a range of temperatures, pH, and concentrations of the microgels. The PNIPAM-co-PAA microgels were proven to have excellent anti-friction and anti-wear properties, depending on the temperature and pH values of the solutions. The maximum friction coefficient coincided with the lower critical solution temperature of the PNIPAM-co-PAA microgels at 32 °C. At the same time, the friction coefficient increased with the increase in pH value of the lubricant solution with the PNIPAM-co-PAA microgels. The unique thermal- and pH-sensitive properties of the PNIPAM-co-PAA microgels provided a new strategy for controlling the friction and wear of steel/CoCrMo alloy contacts under aqueous lubrication.