Instrumentação e controle de um macroesclerômetro para análise de revestimentos tribológicos

Abstract

Researches accomplished in developed countries indicate that from 1 to 5% of the gross domestic product (GDP) is spent direct or indirectly to repair parts and components due to the action of wear. The abrasive wear is responsible for 50% of those failures. That has motivated the development of various techniques, equipment and test procedures to simulate field situations. The objective of this work is to present the development, instrumentation, control and validation of an equipment to simulate the scratching action of an indenter. This technique is called sclerometry. By using this technique, the deformation morphology close to wear events can be evaluated due to the interaction of hard particles with technical surfaces. Additionally, the apparent friction coefficient, changes on the wear mechanisms, specific scratching energy and hardness, as well as the adhesiveness of coatings may determined. In this case, coatings are scratched with increasing normal loads, so that one can identify critical loads, from which the coatings begin delaminate from the substrate. The association of this technique with an acoustic emission system helps to identify these critical loads. Results obtained in these work using electroless nickel and other hardfacing coatings attested the effectiveness of this technique when investigation the tribological behavior of hard coatings.