scope:

This standard describes a method for determining the loss of mass of metal powders after heating for a specified time in a reducing atmosphere. This value is commonly referred to as hydrogen loss and approximates the oxygen content of the powder.

Only oxygen from oxides that are reduced by hydrogen gas under the test conditions, is measured. The test does not measure oxygen from oxides such as SiO₂, Al₂O₃, MgO, CaO, BeO, TiO₂.

The loss of mass may also include carbon, sulfur and other impurities that may react with the reducing gas or reaction products. Compensation should be made for this loss.

The loss of mass may include volatile elements, such as cadmium and zinc that are lost through evaporation.

The loss of mass may include oxygen from oxides reduced by carbon, if present.

The overall change in mass may include a mass gain resulting from oxidation or hydride formation of components present in the mixture.

For materials susceptible to reaction with nitrogen, such as stainless steels, the furnace should be purged with an inert gas, such as argon, and reduction carried out in a hydrogen atmosphere.

The loss of mass may include moisture and gases desorbed during the heat cycle.

With the exception of density, for which g/cm³ is the industry standard, SI units are used in this standard. Values in inch-pound units are shown in parentheses and result from conversion in accordance with IEEE/ASTM Standard SI 10. They may be approximate and are only for information.

This standard may involve hazardous materials, operations and equipment. This standard does not purport to address all of the potential safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.