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Transition from Self-Organized Criticality into Self-Organization during Sliding Si3N4 Balls against Nanocrystalline Diamond Films

Transition from Self-Organized Criticality into Self-Organization during Sliding Si3N4 Balls against Nanocrystalline Diamond Films

Authors :
Asad Alamgir Shaikh
Maxim Yashin
Iosif S. Gershman
Pradeep L. Menezes
Andrei Bogatov
Heinar Vagiström
Mart Viljus
Vitali Podgursky
Source :
Entropy, Volume 21, Issue 11, Entropy, Vol 21, Iss 11, p 1055 (2019)
Publication Year :
2019
Publisher :
Multidisciplinary Digital Publishing Institute, 2019.

Abstract

The paper investigates the variation of friction force (Fx) during reciprocating sliding tests on nanocrystalline diamond (NCD) films. The analysis of the friction behavior during the run-in period is the focus of the study. The NCD films were grown using microwave plasma-enhanced chemical vapor deposition (MW-PECVD) on single-crystalline diamond SCD(110) substrates. Reciprocating sliding tests were conducted under 500 and 2000 g of normal load using Si3N4 balls as a counter body. The friction force permanently varies during the test, namely Fx value can locally increase or decrease in each cycle of sliding. The distribution of friction force drops (dFx) was extracted from the experimental data using a specially developed program. The analysis revealed a power-law distribution f-&micro<br />of dFx for the early stage of the run-in with the exponent value (&micro<br />) in the range from 0.6 to 2.9. In addition, the frequency power spectrum of Fx time series follows power-law distribution f-&alpha<br />with &alpha<br />value in the range of 1.0&ndash<br />2.0, with the highest values (1.6&ndash<br />2.0) for the initial stage of the run-in. No power-law distribution of dFx was found for the later stage of the run-in and the steady-state periods of sliding with the exception for periods where a relatively extended decrease of coefficient of friction (COF) was observed. The asperity interlocking leads to the stick-slip like sliding at the early stage of the run-in. This tribological behavior can be related to the self-organized criticality (SOC). The emergence of dissipative structures at the later stages of the run-in, namely the formation of ripples, carbonaceous tribolayer, etc., can be associated with the self-organization (SO).

Details

Language :
English
ISSN :
10994300
Database :
OpenAIRE
Journal :
Entropy
Accession number :
edsair.doi.dedup.....3c53c6f8349688e0ce3f55424c4a4f28
Full Text :
https://doi.org/10.3390/e21111055