1. Scope 1.1 This test method covers the determination of oxygen due to the presence of hydrogen-reducible oxides in copper, tungsten, and iron powders. This test method consists of subjecting a sample of powder to the action of a hydrogen-containing gas under standard conditions of temperature and time and measuring the resulting loss of weight. This test method is useful for copper and iron powders in the range from 0.05 to 3.0% oxygen and for tungsten powder in the range from 0.01 to 0.50% oxygen. This test method does not measure the oxygen contained in oxides such as silicon oxide (SiO2), aluminum oxide (Al2O3), magnesium oxide (MgO), calcium oxide (CaO), titanium dioxide (TiO2), etc. that are not reduced by hydrogen at the test temperatures. For total oxygen content, vacuum or inert gas fusion methods are available. 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for information only. 1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.