Meaning
Analytical technique that measures trace gases such as oxygen, nitrogen, and hydrogen within metal foils, current collectors, or electrode alloys involves melting the specimen in a high-temperature graphite crucible. This process, referred to as melt extraction, extracts the gases into a stream of inert carrier gas for detection by infrared or thermal conductivity sensors. It provides a quality control tool to verify the purity of raw metal stocks.
Chemical Separation
The metal sample is heated to its melting point in a closed furnace, releasing bound oxygen as carbon monoxide and nitrogen and hydrogen as elemental gases. An inert gas carries these released elements through sensitive detectors that calculate the exact concentration of impurities in parts per million. This high-temperature extraction removes all bound gases from the metal matrix, providing a true measure of total bulk impurity.
Quality Control
Quality agreements for ultra-thin copper and aluminum foil suppliers specify maximum gas concentrations determined by this method. High concentrations of hydrogen or oxygen can embrittle the foils, leading to tearing during the high-speed roll-to-roll coating process. Sourcing teams use these analytical reports to screen foil shipments and prevent costly disruptions on the coating lines.
Volatile Metal
Aluminum or lithium alloys with very low boiling points can vaporize and coat the optical path of the analyzers. Special lower-temperature fusion techniques or sample encapsulation are required to test these highly volatile metal grades.
