Avaliação das propriedades mecânicas do revestimento NiP/Alumina sobre a liga de alumínio 6351-T6

Abstract

Actions involving surface plating are widely used in situations where an increase the lifespan of material is desired. The Electroless nickel-phosphorus plating with Alumina is a viable alternative for this situation, since it presents a uniform deposition, in addition to having favorable mechanical properties for surface protection. In this project, the Electroless nickel-phosphorus plating was carried in aluminum alloy 6351-T6, whereupon 6 groups of samples with different concentrations of Alumina were separated, with and without heat treatment (post deposition). Initially, the samples went through the surface preparation process for carrying the deposition, compact a degreasing bath in acetone for 2 minutes and a surface activation adhesion bath in 40mL/L HCl for 2 minutes. The preparation of the deposition bath was established according to previously defined parameters, like for time bath, temperature, pH, concentration and size of Alumina particles. After deposition and definition of the purposes of the samples, the groups 2, 4 and 6 went through the heat treatment process for 16 hours at a temperature of 250 oC, being possible to analyze its interference in the mechanical resistance of the samples and the behavior with the different concentrations of Alumina in the deposition. For analysis of deposition on the surface, microhardness and wear tests were carried out, to verify the influence of deposition on the microhardness values and resistance to abrasive and adhesive wear of the material.