Improvement of Compact Electron-Beam-Excited Plasma Source for Increased Producible Plasma Density

Abstract

Multiple modifications of graphite electrodes of a compact electron-beam-excited plasma (EBEP) source to enhance the cooling efficiency of the electrodes resulted in an increase in the maximum value of producible EBEP density. In addition, experiments on surface nitriding of steel samples in nitrogen EBEP demonstrated that the improved compact EBEP source with modified electrodes outperforms one with conventional electrodes, thereby demonstrating the significant advantage of using the improved source for a wide range of industrial and scientific applications.

Bright nitriding using atmospheric-pressure pulsed-arc plasma jet based on NH emission characteristics

“…The sample is a circular disk (20 mm in diameter and 4 mm in thickness) of tool steel JIS SKD61 which is frequently used to benchmark nitriding treatments. 4,7,12,18) The composition is as follows: 0.38% C, 0.42% Mn, 0.92% Si, 5.12% Cr, 1.19% Mo, and 0.8% V. The hardness of the base material is adjusted to 550 HV by heat treatment. The surface is mirror-finished with alumina powder and degreased in an ultrasonic acetone bath.…”

Investigation on Hard-Tissue Compatibility of TiN Surface Formed by Atmospheric-Pressure-Plasma Nitriding

“…For practical applications of TiN formation, conventional plasma nitriding methods have several disadvantages owing to large vacuum systems [19][20][21][22][23][24][25][26][27][28][29][30][31], which complicate treatment processes and cause difficulties in self-manufacturing in medical/dental fields. To resolve these disadvantages, this study investigated a novel nitriding method using atmospheric-pressure plasmas.…”

Atmospheric-pressure-plasma nitriding of titanium alloy

“…More importantly, it is well known that nitriding can yield a hard layer, called the diffusion layer, beneath the titanium nitride layer. [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] The consequent improvements in the mechanical properties such as surface hardness and wear resistance will promote titanium further as a material for biomedical components.…”

“…In general, plasma nitriding is performed under low pressure so that the conventional method requires vacuum systems and a long treatment time. [14][15][16][17][18][19][20][21][22][23][24][25][26][27] In order to eliminate these shortcomings of conventional plasma nitriding, we have developed a new plasma-jet nitriding technology operated under atmospheric pressure. Other advantages of atmospheric-pressure operation include the ability to produce high-density reactive species and the absence of electric-field concentration, in contrast to low-pressure plasmas.…”