Contribuţii privind studiul comportării la uzură a unor compozite cu matrice polimerică destinate recondiţionării pieselor metalice

Abstract

The twentieth century has established a new category of material: polymeric materials that have a highly used in almost all areas of social-economic life. From this kind of materials to the polymer composites ones and thereafter ceramic and metal composites, there was only a step. Various fields of science and technology are the beneficiaries of such material and / or polymer composites: medicine - bone prostheses and dental implants, aerospace industry- low-density components and high mechanical characteristics, automotive, packaging industry, etc Some characteristics made these composite materials attractive: high ratio between mechanical properties and density, good mechanical strength and rigidity, corrosion resistance, chemical and impact resistant, thermal stability, insulating properties, the possibility to design their properties depending on the properties of parts, simple production technology, can achieve final surface without further processing, etc.. This paper started from the idea of identifying composite materials for reconstructing large parts of brass or bronze. These materials must be mechanically and tribologicaly compatible with the refurbished pieces, in order to provide a simple technology for refurbishment and being at the same time economical. Out of the many commercial materials available on the market, we chose three items sold by Diamond Metallplastic GmbH "in Munich, Germany, a company with outstanding results achieved in the maintenance and refurbishing metallic industrial parts. They are reinforced polymeric composites that contain metallic and inorganic particles based on Cu, Zn, Sn, MoS, and various allotropic forms of silicon dioxide (SiO2). They are obtained by mixing two components until a paste or fluid is obtained, which is then applied on the damaged surface, followed by hardening at room temperature over a period of time up to 24 hours. The research in this paper focused on the tribological study of these polymer composites. Friction tests were conducted without lubrication in ball-on-flat configuration, in alternative linear motion and in scratch tests, in order to mechanically characterize these materials. In parallel, under the same testing conditions were investigated the following metallic materials: brass and bronze.