Determine the hydrogen content (at low levels <2 ppm) in your aluminum, other metals, refractories, and inorganic materials with our RHEN602. Multiple method selections assure optimal furnace and analysis settings for each sample matrix. Onboard diagnostics minimize your downtime and keep your lab running smoothly.
The RHEN602 hydrogen by inert gas fusion system is designed for precise measurement of hydrogen content of steel, refractory metals, aluminum alloys, and other inorganic materials. A pre-weighed sample is placed in a graphite crucible which is heated in an impulse furnace to release analyte gases. Oxygen present in the sample reacts with the graphite crucible to form CO and CO2. Nitrogen and hydrogen are extracted as N2 and H2 respectively. Argon carrier sweeps the liberated analyte gases out of the furnace. The gas then flows through Schutze reagent where the CO is oxidized to form CO2. The CO2 and any H2O present is then scrubbed out of the carrier gas stream, leaving nitrogen and hydrogen. A patented Dynamic Flow Compensation (DFC) system is used to add carrier gas as a makeup for the gas lost during the scrubbing process. A molecular sieve column separates the nitrogen from the hydrogen. The smaller hydrogen molecule passes through the sieve mores more quickly than the larger nitrogen molecule, and is detected using a Thermal Conductivity (TC) detector. The nitrogen molecules are then allowed to pass through undetected.
TC detection takes advantage of the difference in thermal conductivity between carrier and analyte gases. Resistive TC filaments are placed in a flowing stream of carrier gas and heated by a bridge circuit. As analyte gas is introduced into the carrier stream, the rate at which heat transfers from the filaments will change, resulting in a measurable deflection in the bridge circuit. TC detectors are inherently linear and have high sensitivity. The concentration of an unknown sample is determined relative to calibration standards. To reduce interferences from instrument drift, reference measurements of pure carrier gas are made prior to each analysis.
The RHEN602 features advanced furnace control and associated software that supports the separation and measurement of surface and bulk hydrogen in aluminum and aluminum alloy samples, especially at low levels (<2 ppm). This is done in accordance with ASTM Standard E2792, 2013, “Standard Test Method for Determination of Hydrogen in Aluminum and Aluminum Alloys by Inert Gas Fusion,” ASTM International, West Conshohocken, PA, www.astm.org.
Hydrogen in Aluminum [PDF]