Generation of Electron and Fast Atom Beams by a Grid Immersed in Plasma

Alexander Metel,Khaled Hamdy,Yury Melnik,Enver Mustafaev

doi:10.1051/epjconf/202124804001

Alexander Metel, Khaled Hamdy + Show 2 more

Open Access

https://doi.org/10.1051/epjconf/202124804001

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Abstract

We present a new method of product processing with beams of accelerated electrons and fast neutral atoms, which are generated by an immersed in plasma grid under a high negative voltage of 5 kV. The electrons appear due to secondary emission from the grid surface provoked by its bombardment with ions accelerated from the plasma. At the gas pressure not exceeding 0.1 Pa the ions with energy of 5 keV reach the grid without collisions in the space charge sheaths near its surface and their current in the grid circuit is by 2-3 times lower than the electron current. At higher pressures accelerated ions due to charge exchange collisions in the sheaths turn into fast neutral atoms leaving the sheaths and forming the beams. With the pressure increasing, the electron beam current diminishes and the current of fast atom beam grows.

Highlights

The ion-plasma processing of engineering products allows a modification of their surface properties
Using the plasma immersion ion implantation [1,2,3], materials can be modified and alloying additives can be introduced into the surface layer
Ion-plasma treatment reduces the coefficient of friction, increases the useful life of the products, significantly increases their wear resistance and corrosion resistance

Summary

Introduction

The ion-plasma processing of engineering products allows a modification of their surface properties. Ion-plasma treatment reduces the coefficient of friction, increases the useful life of the products, significantly increases their wear resistance and corrosion resistance It allows for combined treatment, for example, ion nitriding of products [6, 7] with subsequent deposition of wear-resistant coatings. In the latter case, a hardened nitride surface layer with a thickness of 50–100 μm prevents brittle fracture of hard coatings with a thickness not exceeding 5 μm. It is impossible to apply high-voltage pulses to dielectric products and for this reason, broad beams of accelerated ions [13, 14] or fast neutral atoms [15, 16] are used to bombard the product surface. It is necessary first to develop a model of the beam generation allowing for prediction of the beam parameters dependence on the gas pressure and the discharge current

Beams produced by a flat grid

Findings

Experimental study of the fast atom beam formation by a concave grid