Aspectos experimentais do comportamento em microabrasão de poliuretano

• Ano de defesa: 2009
• Autor(a) principal: Velten, Samuel Berger
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Espírito Santo; BR; Mestrado em Engenharia Mecânica; Centro Tecnológico; UFES; Programa de Pós-Graduação em Engenharia Mecânica
• Palavras-chave em Português: Engenharia mecânica; 621
• Link de acesso: http://repositorio.ufes.br/handle/10/4138

This work is carried out a comparative study of abrasive wear resistance of 8 formulations of polyurethane. The test used in this study was the microabrasion with fixed ball. The normal force was kept constant and two 2 loads are used, 0.75 and 1.0 N. The abrasive slurry was prepared in the ratio 20 g of abrasive to 100 ml of distilled water. The abrasive used was silica (SiO2) with particle size ranging from 0.2 to 5 micrometers. To determine the steady-state wear regime tests were performed in the following time intervals: 15, 30, 45, 60, 75, 90 and 120 minutes. The wear scar produced in each time interval was recorded via optical imaging. It was observed that the wear coefficient remains relatively constant from the time intervals that lasted more than 45 minutes, featuring steady wear regime. At least six batteries of tests for each formulation were carried out. The topography of the wear scar was obtained by three-dimensional topographic analysis, which allowed us to determine if a spherical cap was formed. Also the volume of each cap was obtained. The wear mechanism was evaluated using scanning electron microscopy. The wear micro-mechanisms observed show variations. Most of the formulations presented indentation as the predominant wear mechanism; it was also identified the presence of micro-cracks, microploughing/microcutting and formation of protuberances and ridges.