Development and construction of chambers for metals sintering in special atmospheres

Resumo

Powder metallurgy is a manufacturing process of units in which the raw material comes in form of power. The microstructural control and technological necessity to produce certain metallic and ceramic components by using this technique has some advantages since the thermal process is done by something called sintering. The power source is commonly used in the sintering process is the resistive oven which can work or not in the vacuum environment. However, in recent decades, the plasma sintering technique has emerged as an alternative heat source. In this technique, heat is provided by the ion bombardment of neutral atoms, electrons, and by the heat radiation generated by this plasma. In this case, in addition to microstructural control by powder metallurgy, sintering aided by plasma favors the atomic sputtering from the cathode material so there will be deposition and consequential atomic diffusion of elements on the substrate of the sintering sample. Since that the vacuum sintering resistive furnace, heat is provided by heating an electric resistance, however, as it comes to sintering of a metal component, the protective oxidation occurs through a vacuum atmosphere. For both techniques, the vacuum chamber is one of the key elements of a vacuum system to prevent contamination of the sample and allowing the generation and maintenance of plasma in the temperature process. For the construction of these chambers, attention is required in the materials specification involvement in the manufacture of these contacted surfaces and welding, to ensure effective vacuum system. Therefore, this work has as main purpose to show the development of two sintering chambers, which are already in use: (a) one for vacuum resistive oven; and (b) another one for cold plasma of Hydrogen and Argon.