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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Influence of the chemical surface structure on the nanoscale friction in plasma nitrided and post-oxidized ferrous alloy

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Autor(es):
Freislebem, Marcia [1] ; Menezes, Caren M. [1] ; Cemin, Felipe [1] ; Costi, Fernanda B. [1] ; Ferreira, Patricia A. [1] ; Aguzzoli, Cesar [1] ; Baumvol, Israel J. R. [1, 2] ; Alvarez, Fernando [3] ; Figueroa, Carlos A. [1, 4]
Número total de Autores: 9
Afiliação do(s) autor(es):
[1] Univ Caxias do Sul, Ctr Ciencias Exatas & Tecnol, BR-95070560 Caxias Do Sul, RS - Brazil
[2] Univ Fed Rio Grande do Sul, Inst Fis, BR-91509970 Porto Alegre, RS - Brazil
[3] Univ Estadual Campinas, Inst Fis Gleb Wataghin, BR-13081970 Campinas, SP - Brazil
[4] Plasmar Tecnol Ltda, BR-95076420 Caxias Do Sul, RS - Brazil
Número total de Afiliações: 4
Tipo de documento: Artigo Científico
Fonte: Applied Physics Letters; v. 105, n. 11 SEP 15 2014.
Citações Web of Science: 5
Resumo

Friction is a ubiquitous phenomenon in everyday activities spanning from vehicles where efficient brakes are mandatory up to mechanical devices where its minimum effects are pursued for energy efficiency issues. Recently, theoretical models succeed correlating the friction behavior with energy transference via phonons between sliding surfaces. Therefore, considering that the energy losses by friction are prompted through phonons, the chemical surface structure between sliding surfaces is very important to determine the friction phenomenon. In this work, we address the issue of friction between a conical diamond tip sliding on different functionalized flat steel surfaces by focusing the influence of the chemical bonds in the outermost layers on the sliding resistance. This geometry allows probing the coupling of the sharp tip with terminator species on the top and underneath material surface at in-depth friction measurements from 20 to 200 nm. Experimentally, the friction coefficient decreases when nitrogen atoms are substituted for oxygen in the iron network. This effect is interpreted as due to energy losses through phonons whilst lower vibrational frequency excitation modes imply lower friction coefficients and a more accurate adjustment is obtained when a theoretical model with longitudinal adsorbate vibration is used. (C) 2014 AIP Publishing LLC. (AU)

Processo FAPESP: 12/10127-5 - Pesquisa e desenvolvimento de materiais nanoestruturados para aplicações eletrônicas e de física de superfícies
Beneficiário:Fernando Alvarez
Linha de fomento: Auxílio à Pesquisa - Temático