Vliv proteinů na tloušťku mazacího filmu v kontaktech mazaných hovězím sérem

Effect of Proteins on Film Formation in Bovine Serum Lubricated Contacts

článek ve sborníku ve WoS nebo Scopus

en

The aim of this study is to perform detail experimental mapping of the lubricating film thickness of bovine serum (BS) within the contact between an artificial metal or ceramic femoral head and a glass disc and analyze effect of proteins on the film formation. Mapping of the lubricating film of various concentrations of BS solutions was carried out using an optical test rig which is schematically displayed in Fig. 1. Chromatic interferograms were recorded with a high-speed digital camera and evaluated with thin film colorimetric interferometry (Fig. 1). The film thickness was studied as a function of both time and mean speed. The results showed that film thickness increases with time for both the metal and ceramic heads. Films formed at the end of measurements with the metal head were found to be typically in the range of 60-100 nm for all BS solutions and were independent on the amount of proteins in tested fluids. At the beginning of the speed measurements, BS of all concentrations forms a very thin film (1-2 nm) and its thickness increases with increasing mean speed. However, when the speed was decreased, the film thickness did not reduce but increased with decreasing speeds that supports the findings of other researchers. Moreover, it was found that BS supply is sensitive parameter. When the lubricant reservoir below tested head was used then the measured central film thicknesses achieved values only about 20 nm, whereas when the tests were realized without the reservoir, measured central film thicknesses achieved higher values about 100 nm. For both types of the experiments, distribution of the film thickness within the contact zone is not homogeneous and two different film thickness regions can be found; thicker protein film and thinner base film that both increase with time and speed (Fig. 2).

Tento článek se zabývá experimentálním studiem vlivu proteinů na tloušťku mazacího filmu v kontaktech mazaných hovězím sérem.

The aim of this study is to perform detail experimental mapping of the lubricating film thickness of bovine serum (BS) within the contact between an artificial metal or ceramic femoral head and a glass disc and analyze effect of proteins on the film formation. Mapping of the lubricating film of various concentrations of BS solutions was carried out using an optical test rig which is schematically displayed in Fig. 1. Chromatic interferograms were recorded with a high-speed digital camera and evaluated with thin film colorimetric interferometry (Fig. 1). The film thickness was studied as a function of both time and mean speed. The results showed that film thickness increases with time for both the metal and ceramic heads. Films formed at the end of measurements with the metal head were found to be typically in the range of 60-100 nm for all BS solutions and were independent on the amount of proteins in tested fluids. At the beginning of the speed measurements, BS of all concentrations forms a very thin film (1-2 nm) and its thickness increases with increasing mean speed. However, when the speed was decreased, the film thickness did not reduce but increased with decreasing speeds that supports the findings of other researchers. Moreover, it was found that BS supply is sensitive parameter. When the lubricant reservoir below tested head was used then the measured central film thicknesses achieved values only about 20 nm, whereas when the tests were realized without the reservoir, measured central film thicknesses achieved higher values about 100 nm. For both types of the experiments, distribution of the film thickness within the contact zone is not homogeneous and two different film thickness regions can be found; thicker protein film and thinner base film that both increase with time and speed (Fig. 2).

Umělý kyčelní kloub, Hovězí sérum, Tloušťka filmu, Kolorimetrická interferometrie

Artificial hip joint, Bovine serum, Film thickness, Colorimetric interferometry

2012

12.06.2012

Norwegian University of Science and Technology

Trondheim, Norway

978-82-14-05270-1

15th Nordic Symposium on Tribology (NORDTRIB 2012)

1

91–91

1