The use of graphite for the removal of oxygen from nitrogen purge gas in high temperature microthermometry using the Linkam® TH1500 stage
Oskarsson, Niels; Hansteen, Thor H.
European Journal of Mineralogy Volume 4 Number 5 (1992), p. 865 - 872
published: Oct 14, 1992
manuscript accepted: Nov 21, 1991
manuscript received: Jun 11, 1991
ArtNo. ESP147050405021, Price: 29.00 €
Abstract Gas compositions attained inside the heating chamber of a Linkam® TH1500 heating stage in the temperature interval 400 to 1341 °C were measured with a quadrupole mass analyzer. A small ring of spec, pure carbon was placed inside the chamber, and the system continuously purged with commercial grade nitrogen gas. Effective burning of C, converting trace amounts of O2 in the purge gas to CO2 and probably also to CO, occurred at temperatures above 600 °C, where a steady state was approached in less than 2 minutes. Based on measurements of gas compositions and inferences about mass balance, the maximum partial pressure of oxygen at 1300 °C was estimated at 10-17 bar. In order to minimize deposition of volatile salts derived from natural samples in the optical pathway of the stage during ordinary microthermometric runs, the gas circulation pattern was slightly modified.