10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Effect of O2/N2 Ratio on the Generation of Self-Charged Positive and Negative Sub 5 nm with a Glowing Wire
MICHEL ATTOUI, LISA, Université Paris Est Créteil France
Abstract Number: 989 Working Group: Instrumentation
Abstract Ultrafine particles generation with resistive heating wires (platinum, nickel, steel, tungsten etc…) in noble gases (argon, nitrogen, helium etc…) have been used since 1950s. Detection and sizing aerosol metrology (differential mobility analyzer coupled to atmospheric pressure mass spectrometers) highlighted the last decades that the lower limit in generated particles size of the method is around the atomic level.
The glowing wire method is mostly used with inert gases as carrier gases (nitrogen, helium or argon) to prevent contamination and especially oxidation.
Oxidation at high temperature on the other hand makes the wire very fragile and incapable to resist to a frequent breakages. However NiCr wire is the exception which is used in many industrial applications at high temperatures (ovens, heating, cooking etc…). This study focuses on the characterization of the glowing wire generator with a NiCr wire in a mixture of dry nitrogen-oxygen as carrier gas. The ratio of oxygen in nitrogen varies from 0 to 20 %.
The study is limited to sub 5 nm particles range in terms of size distribution of positive and negative self-charged particles with a high resolution DMA. The flowrate inside the glowing wire chamber varies from 10 to 50 lpm to prevent the growth of particles by coagulation.