Sintering Iron Using a Hollow Cathode Discharge with External Ti Cathode

Abstract

Unalloyed iron samples were sintered in the presence of a hollow cathode glow discharge, generated in a gas mixture of 80% Ar + 20% H 2 at a pressure of 400 Pa. The sample, which worked as the inner cathode of the discharge, was heated by the bombardment of strongly accelerated ions and fast neutrals created in the cathode sheath. The outer cathode of the hollow geometry consisted of a titanium cylinder. The samples were sintered at different temperature, 1050, 1150 and 1250 °C for 60 minutes. The temperature was adjusted by varying the time on/off of the pulsed power supply used to generates the discharge. Microstructural results are presented and show that samples may be successfully sintered in a hollow cathode discharge. In addition, Ti atoms sputtered from the outer cathode were deposited onto the sample surface and by diffusion, during sintering, resulted in the formation of a layer approximately 100 μm thick containing 1 at.% Ti.