Journal Article


Denis P. Dowling
Vladimir Milosaviljevic
Aidan Breen



microwave plasmas 316l stainless steel x ray diffraction energy efficient microwave plasma thermal measurements emission spectroscopy sintering

Influence of gas type on the thermal efficiency of microwave plasmas for the sintering of metal powders (2011)

Abstract Microwave plasmas have enormous potential as a rapid and energy efficient sinteringtechnology. This paper evaluates the influence of both plasma atmosphere and metalpowder type on the sintering temperatures achieved and the properties of the sinteredpowder metal compacts. The sintering is carried out using a 2.45 GHz microwave-plasmaprocess called rapid discharge sintering (RDS). The sintering of three types of metalpowder are evaluated in this study: nickel (Ni), copper (Cu) and 316L stainless steel (SS).An in-depth study of the effects of the plasma processing parameters on the sinteredpowder compacts are investigated. These parameters are correlated with the mechanicalperformance of the sintered compacts to help understand the effect of the plasma heatingprocess. The substrate materials are sintered in four different gas discharges, namelyhydrogen, nitrogen oxygen and argon. Thermocouple, pyrometer and emissionspectroscopy measurements were taken to determine the substrate and the dischargetemperatures. The morphology and structure were examined using scanning electronmicroscopy and x-ray diffraction. The density and hardness of the sintered compacts werecorrelated with the plasma processing conditions. As expected higher densities wereobtained with powders with lower sintering temperatures i.e. nickel and copper whencompared with stainless steel. Under the power input and pressure conditions used thehighest substrate temperature attained was 1100∘C for Cu powder sintered in a nitrogenatmosphere. In contrast under the same processing conditions but in an argon plasma, thetemperature achieved with SS was only 500∘C. The effect of the plasma gas type on thesintered powder compact chemistry was also monitored, both hydrogen and nitrogenyielded a reducing effect for the metal in contrast with the oxidising effect observed in anoxygen plasma.
Collections Ireland -> University College Dublin -> Mechanical & Materials Engineering Research Collection
Ireland -> University College Dublin -> College of Engineering & Architecture
Ireland -> University College Dublin -> School of Mechanical and Materials Engineering

Full list of authors on original publication

Denis P. Dowling, Vladimir Milosaviljevic, Aidan Breen

Experts in our system

Denis P. Dowling
University College Dublin
Total Publications: 50