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Study of the micro surface irregularities (texture and porosity) effect on the tribological behavior of a steel sintered by SPS

Grant number: 16/25067-9
Support type:Scholarships in Brazil - Doctorate (Direct)
Effective date (Start): April 01, 2017
Effective date (End): September 30, 2019
Field of knowledge:Engineering - Mechanical Engineering - Manufacturing Processes
Principal researcher:Izabel Fernanda Machado
Grantee:Guido Boidi
Home Institution: Escola Politécnica (EP). Universidade de São Paulo (USP). São Paulo , SP, Brazil
Associated scholarship(s):17/21151-8 - Tribological effect of micro surface irregularities (surface porosity and texture) on lubricated sliding/rolling tests, BE.EP.DD


This PhD project proposal aims the evaluation and analyses of the tribological behavior influence of porous of sintered steel and the surface texture. Low carbon steels with different chemical compositions were evaluated. Therefore, a phenomenological and/or analytical model will be proposed to establish this relationship between the surface features and wear/friction mechanisms. The steel was manufactured by Spark Plasma Sintering Technique (SPS). The material characterization was carried out by relative density (Archimedes method) determination and microstructural analysis (Optical Microscopy (LOM), Scanning Electron Microscopy (SEM), semi - quantitative chemical analysis, EDS-SEM), X-ray diffraction and X-ray tomography. The mechanical properties were evaluated by hardness and micro-hardness tests. Consolidated materials were also characterized in terms of wear and friction during lubricated tests, in which sliding/rolling condition was different and varied from predominant rolling to predominant sliding, with non-compliant point contact. A device, adapted into a Bruker tribometer, was used, since it allows varying the Slide-to-Roll Ratio (SRR) by changing the tilt angle of a roller with respect to the specimen. These materials had a potential application for manufacturing sintered gears. The effect of morphology, features, orientation and micro- irregularities size (texture and porosity) were studied in different lubrication regimes and SRR as described above. In order to determine coefficients of friction and wear resistance, material tests were conducted at different speeds and SRR. The counter body material was made of the chromium steel AISI 52100. A textured material (or materials) will be used as a reference and be compared with sintered steel. This Texturing was achieved by laser, and will be conducted at the IPT, IPEN, INPE or in a private company. The expected result was to obtain an analytical or phenomenological model that contributes to understanding how micro-irregularities (texture and porosity) could change lubricant conditions and increase the efficiency of mechanical systems. (AU)

Scientific publications (4)
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
BOIDI, G.; PROFITO, F. J.; KADIRIC, A.; MACHADO, I. F.; DINI, D. The use of Powder Metallurgy for promoting friction reduction under sliding-rolling lubricated conditions. TRIBOLOGY INTERNATIONAL, v. 157, MAY 2021. Web of Science Citations: 0.
BOIDI, G.; GRUETZMACHER, P. G.; KADIRIC, A.; PROFITO, F. J.; MACHADO, I. F.; GACHOT, C.; DINI, D. Fast laser surface texturing of spherical samples to improve the frictional performance of elasto-hydrodynamic lubricated contacts. FRICTION, v. 9, n. 5 JAN 2021. Web of Science Citations: 2.
BOIDI, GUIDO; DA SILVA, MARCIO RODRIGUES; PROFITO, FRANCISCO J.; MACHADO, IZABEL FERNANDA. Using Machine Learning Radial Basis Function (RBF) Method for Predicting Lubricated Friction on Textured and Porous Surfaces. SURFACE TOPOGRAPHY-METROLOGY AND PROPERTIES, v. 8, n. 4 DEC 2020. Web of Science Citations: 0.
BOIDI, G.; TERTULIANO, I. S.; LIMA, L. G. B. S.; PROFITO, F. J.; MACHADO, I. F. Porosity Effect of Sintered Steel on the Frictional Performance of Conformal and Nonconformal Lubricated Contacts. TRIBOLOGY TRANSACTIONS, v. 62, n. 6 AUG 2019. Web of Science Citations: 0.

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