Síntese e caracterização de um filme de óxido tipo espinélio obtido durante o tratamento de envelhecimento do aço maraging 300 em atmosfera de N2/vapor

Abstract

The aging treatment in maraging steels is very important for to acquire excellent mechanical properties, reasons of their applications in several types of industries. In nuclear industry, the initial motivation of this investiation, maraging steels are used in ultra-centrifugal parts for uranium enrichment. In view of this, this study aimed to producing, during the heat treatment, an oxide film that behaves as a protective layer for maraging steel against atmospheric attack. Aging was carried out in a controlled atmosphere furnace (a combination of nitrogen and water vapor). Due to the thermodynamic and kinetic conditions, these gases reacted with the steel, producing an oxide on the surface. For the accomplishment of the experiment it was necessary to carry out the metallographic study of the samples. By means of the techniques of Scanning Electron Microscopy (SEM), X-ray Dispersive Energy Spectroscopy (EDS) and X-ray Diffraction (DRX), the film was characterized as a compact adherent oxide with iron spinel microstructure with nickel and cobalt.