title: Effect of aqueous solution and load on the formation of DLC transfer layer against Co-Cr-Mo for joint prosthesis.
abstract: Diamond-like carbon (DLC) coating exhibits excellent mechanical properties such as high hardness, low friction and wear, which offer a promising solution for the metal-on-metal hip joint implants. In the study, the hydrogen-free DLC coating with the element Cr as the interlay addition was deposited on the surface of the Co-Cr-Mo alloy by a unbalanced magnetron sputtering method. The coating thickness was controlled as 2 µm. Nano-indentation test indicated the hardness was about 13 GPa. DLC coated Co-Cr-Mo alloy disc against un-coated Co-Cr-Mo alloy pin (spherical end SR9.5) comprised the friction pairs in the pin-on-disc tribotest under bovine serum albumin solution (BSA) and physiological saline(PS).The tribological behavior under different BSA concetrations(2-20 mg/ml), and applied load (2-15N) was investigated.DLC transfer layer did not form under BSA solution, even though different BSA concetration and applied load changed. The coefficient of friction(COF) under 6 mg/ml BSA at 10 N was the lowest as 0.10. A higher COF of 0.13 was obtained under 20 mg/ml BSA. The boundary absorption layer of protein is the main factor for the counterparts. However, the continous DLC transfer layer was observed under PS solution, which make a lower COF of 0.08.
authors.affiliation: Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, PR China.
authors.forename: Feifei
authors.initials: F
authors.lastname: Guo
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, China.
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Hua
authors.affiliation: Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, PR China. Electronic address: donggn@mail.xjtu.edu.cn.
authors.forename: Guangneng
authors.initials: G
authors.lastname: Dong
mesh_terms: D000497:Alloys / Q000737:chemistry*; D000818:Animals; D002417:Cattle; D002857:Chromium / Q000737:chemistry; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry; D018130:Diamond / Q000737:chemistry*; D017276:Friction; D006244:Hardness; D007595:Joint Prosthesis; D008422:Materials Testing; D008982:Molybdenum / Q000737:chemistry; D012996:Solutions; D014867:Water / Q000737:chemistry*; D016474:Weight-Bearing
chemical_list: D000497:Alloys; D020099:Coated Materials, Biocompatible; D012996:Solutions; D014867:Water; D002857:Chromium; D003035:Cobalt; D018130:Diamond; D008982:Molybdenum
keywords: BSA; Co–Cr–Mo; DLC coating; Friction; Transfer layer; Wear