Statistical Cluster and Regression Evaluation of Friction Coefficient in Extremely Thin Diamond-Like Carbon Films | Chapter 1 | Physical Science: New Insights and Developments Vol. 2

 

Extremely thin diamond-like carbon (DLC) films are commonly used for nanotribological applications as a protective film. Atomic-scale wear and minute fluctuations in friction degrade equipment performance. Thus, improving the nanotribology of these protective films is crucial for realising higher reliability in nano-systems. The tribological properties of extremely thin DLC films at high temperature were studied. The films were deposited on nickel phosphorus (NiP) or Si substrates using filtered cathodic vacuum arc (FCVA) or plasma chemical vapour deposition (P-CVD). The nanotribological properties of the films were investigated using AFM. To evaluate how the friction durability properties of the film depend on load, the friction coefficient was measured using a load-increase and decrease type friction tester. Cluster analysis of the dependence of the friction coefficient on load and number of reciprocating cycles was performed on the data from the friction test using statistical analysis. The nanoindentation hardness values and elastic moduli of the films were lower on NiP than on Si. The nanofriction force of the FCVA-DLC film on NiP was low at room temperature, but very high at high temperatures. In this hard film, the lubricous adsorbate was removed by sliding at high temperature, making it easily damaged through the large deformation of NiP. In contrast, the friction force of the P-CVD-DLC films on both substrates was low at high temperatures. In this case, the lubricous tribochemical products from the P-CVD-DLC film reduced friction and wear. The friction map dependencies on load and number of reciprocating cycles were evaluated using a friction test and statistical cluster analysis. In contrast to the FCVA-DLC film, the friction coefficient of the P-CVD-DLC film is relatively high at room temperature; however, the friction coefficient decreases at high temperature, associated with an increase in durability and critical load. The friction durability of both films depended more strongly on load on NiP than on Si, with the friction coefficients on Si being almost independent of load. At high temperatures and loads, the durability of the FCVA-DLC film on NiP decreased, and this film was easily damaged. Low friction and better durability at high temperature can be obtained for this P-CVD-DLC film; this is evident in the superior nanofriction and wear properties of the film at high temperature.

 

Author(s) Details

Shojiro Miyake
MS Laboratory, 3-1, Gonokami, Hamra-City, Tokyo 205-0011, Japan and Nippon Institute of Technology, 4-1, Miyashito-Machi, Minamisaitama, Saitama, 345-8501, Japan.

 

Masatoshi Miyake
MS Laboratory, 3-1, Gonokami, Hamra-City, Tokyo 205-0011, Japan and Nishogakusya University, 6-16, Sanbancho, Chiyoda-Ku, Tokyo 102-8336, Japan.

 

Please see the book here:- https://doi.org/10.9734/bpi/psniad/v2/5877