Investigation into the operating characteristics of a ''microarc'' atmospheric-pressure glow discharge

Journal Article · Tue May 01 00:00:00 EDT 1979 · Appl. Spectrosc.; (United States)

DOI:https://doi.org/10.1366/0003702794925840· OSTI ID:6259909

Bystroff, R I; Layman, L R; Hieftje, G M

Details of the processes occurring during sample atomization from a ''microarc'' discharge have been studied photometrically, by use of high-speed color cinematography and through current-voltage waveforms. The microarc studied here is an atmospheric-pressure inert-gas glow discharge supported between 0.25 mm diameter tungsten wires; quiescent argon-1% H/sub 2/ provides reactive-sputtering conditions and improved behavior in the presence of oxygen impurities. Excitation temperatures of ca. 5000 /sup 0/K are measured for the argon glow. Samples of Na, Al, and Sr illustrate the influence of votatile, refractory, insulating, and electron-emitting sample properties on the temporal-spatial-electrical behavior of the discharge. The step-by-step events occurring in the discharge are described qualitatively and a variety of proceses are invoked to explain sample volatization, including sputtering, chemical reactions, and purely thermal effects. In the first stages of the discharge, instabilities are related to the placement and insulating character of deposits. With heating, electron emission becomes important in directing the discharge to or away from the sample; abnormal glow wandering and glow-to-arc transitions can ensue. Improved stability is achieved by uniformly depositing multi-element samples along the electrode, which localizes the initial discharge and promotes ablative cooling of the sample and electrode.

• Research Organization: Department of Chemistry, Lawrence Livermore Laboratory, Livermore, California 94550
• OSTI ID: 6259909
• Journal Information: Appl. Spectrosc.; (United States), Vol. 33:3
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
GLOW DISCHARGES
OPERATION
MULTI-ELEMENT ANALYSIS
ATOMIZATION
DESIGN
ELECTRIC ARCS
PERFORMANCE
SPECIFICATIONS
STABILITY
CHEMICAL ANALYSIS
CURRENTS
ELECTRIC CURRENTS
ELECTRIC DISCHARGES
400100* - Analytical & Separations Chemistry
640420 - Fluid Physics- Properties & Structure of Fluids- (-1987)