Effect on Decrease of Oxygen Blank by Addition of Silicon or Chromium in Determination of Oxygen by Vacuum Fusion Method
Year: 1987
Type: article
Abstract: A conventional vacuum fusion method which is used as a standarization method of oxygen contents in metals has a disadvantage in being too time-consuming for degassing the graphite crucibles. The addition of a small amount of Si into the graphite crucible rapidly decreased the oxygen blank, and it was also found that Cr gives the same effect as Si. When the crucible was degassed for 1.8 ks at 2573 K after the addition of Si or Cr, the oxygen blank values were reduced under 5 μg/600 s. This technique was suitable for a rapid and accurate determination of oxygen in metals.The mechanism of the rapid decrease of the oxygen blank was assumed as follows:(1) Rapid evaporation of metals on the wall of the graphite crucible in vacuum at 1673-1973 K.(2) Deep penetration of metals into the graphite crucible.(3) Reaction of metals and the oxides in the graphite crucible.(4) Reaction of metal oxides and graphite.(5) Extraction of carbon monoxide in vacuum.
Authors: Morimasa Saito, Emiko Sudo
Language: English
Subfield: Analytical Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2605656345