In this paper, we use Oven Desorption followed by Karl Fischer Titration (KF), to measure moisture content in metal powder. In a PBF-LB Hastelloy X powder, from a newly opened container, we found 28.8 ppm (or µg/g). In a stored PBF-EB powder we found 13.7 ppm. In a stored HIP powder we found 6.7 ppm. This method heats a powder sample inside a hermetically closed vial, in an oven. At the same time an inert gas flow enters, flushes out the desorbed water and exits the vial, via a double hollow needle. The gas–water mixture that exits is directed to the Karl Fischer Titration, where the desorbed moisture is quantified.
Included is also a comparison with thermogravimetric analysis (TGA) and a climate chamber moisturization experiment of a PBF-LB HX powder followed by KF analysis. After the moisturization and KF analysis, the same powder was characterized in terms of oxygen content.
This article appeared in the January–February 2020 issue of Metal Powder Report.
