Surface Hardening of Massive Steel Products in the Low-pressure Glow Discharge Plasma

Abstract

A process vacuum chamber is filled with a homogeneous plasma of glow discharge with electrostatic electron confinement, which is used for surface hardening of massive products. At the current of 2–20 A and the gas pressure ranging from 0.1 to 1 Pa the discharge voltage amounts to 350–500 V. When a bias voltage of 2 kV is applied to an immersed in the plasma hollow cylinder with a mass of 15 kg, electrical power spent on heating it by accelerated ions exceeds by an order of magnitude the power spent on the discharge maintenance. The massive cylinder is heated up to 700 °C for 15 min. When argon mixture with nitrogen (30%) is used, the nitriding for 3h results in an increase in the surface hardness from 400 up to 1000 HV50 and the nitrided layer thickness grows to ~100 μm. The nitriding rate is enhanced by a high degree of nitrogen dissociation due to decomposition by fast electrons and surface structural defects due to bombardment by high-energy ions.

Surface Modification of Dielectric Substrates by Broad Beams of High-Energy Atoms of Inert Gases

“…Hence, their energy exactly corresponds to the amplitude of applied pulses and amounts to 10-100 keV. This allows the surface hardening of massive steel products immersed in plasma [40] and other technological processes. It was shown in [41] that electrostatic confinement of electrons inside a sizeable hollow cathode reduces the gas pressure in the glow discharge to 0.01 Pa.…”

Изучение Диодных Свойств Двойного Слоя Комбинированного Газового Разряда

“…Решение проблемы повышения долговечности осуществляется за счет упрочняющей обработки поверхностного слоя изделий [1][2][3]. К известным методам плазменной упрочняющей обработки относятся: термоупрочнение [4][5][6], ионно-плазменное диффузионное внедрение [7][8][9], ионно-лучевая упрочняющая обработка [10,11], MPACVD-метод (Microwave Plasma Assisted CVD) осаждения поликристаллических алмазных пленок [12][13][14], позволяющие изменять свойства поверхностного слоя и способствующие повышению его твердости.…”