Plasma assisted parts' manufacturing: sintering and surface texturing - part II - influence of inter-cathode distance and gas pressure
Journal of the Brazilian Society of Mechanical Sciences and Engineering
The acquirements and potentiality universe of cleaning, heating and/or sputtering effects caused by plasma species bombardment phenomenon on the surface characteristics and finishing of manufactured parts treated in DC abnormal glow discharge opens a new research and development field, called here of Plasma Assisted Parts' Manufacturing (PAP'M). The adequate control of the sputtering mechanism allows the obtainment of different kinds of surface. Therefore, the design of rough or smooth surface,
... or smooth surface, presenting a modified distribution of surface porosity and texturing could be idealized, in accordance with the desired surface characteristics, as the parts are simultaneously sintered and treated. This is the second part (out of two) of the work performed in hollow cathode discharge (HCD) and it presents the first results of the surface morphology's changes in the pressed iron samples and in the internal surface of the external cathode as a function of the inter-cathode distance and gas pressure. Potential applications include small diameters' cylindrical parts and components like axles, pins, pivots, and tubes and pipes presenting small internal diameters. Sputtering effects were quantified by means of mass loss, and Ra and Rz roughness measurements and qualified by means of SEM. Results indicate the sputtering mechanism is highly dependent of the hollow cathode effect, in HCD sintering and surface texturing treatments, comprising an important contribution to the development of green technologies for surface texturing, surface engineering, and part's manufacturing. respectively. The same was roughly verified in the a = 3.2 mm and 120 min sintering time condition, and a = 5.8 mm and 240 min sintering time (as previously presented in Part I), being of 84.5 at.% Fe and 81.1 at.% Fe, respectively. Finally, the presence of argon in the composition of the processed surfaces is indicative that ions participate in the formation process of the condensed particles, in accordance with the proposed by Romanowsky and Wronikowsky (1992). J. of the Braz. Soc. of Mech. Sci. & Eng.