A review of moisture analysis in metal powders using Karl Fischer titration with oven desorption

The application of oven desorption Karl Fischer titration for the moisture analysis of metal powders will be reviewed. Even very low levels of moisture can have significant impacts on metal powder properties, including flow, consolidation, sintering and surface oxidation, particularly when powder recycling is conducted. Although several techniques can be applied to the measurement of water content in such powders, the results are often inconsistent, ambiguous or exhibit high variability. Karl Fischer can provide high precision, accuracy of a very wide range and excellent repeatability. Nonetheless, its application to metal powders requires specific types of Karl Fischer equipment and procedures, namely oven desorption and coulometric titration. A critical review of published data and procedural details will be used to provide insight into the application of the technique to metal powder additive manufacturing.