4.1 The purpose of this test method is to determine the amount of gangue, refractory, inert, etc. materials, that may adversely affect compacting tools and sintered properties of components formed from copper and iron powders.

4.2 The insoluble matter consists of those nonmetallic substances that do not dissolve in the mineral acid used to dissolve the metal. In copper powder, which is treated with nitric acid, the acid-insoluble matter includes silica, insoluble silicates, alumina, clays, and other refractory materials that may be introduced either as impurities in the raw material or from the furnace lining, fuel, etc.; lead sulfate may also be present. In iron powder, which is treated with hydrochloric acid, the insoluble matter may include carbides in addition to the substances listed above. The test method excludes insoluble material that is volatile at the ignition temperature specified.

1.1 This test method2 covers the determination of the mineral-acid-insoluble matter content of copper and iron powders in amounts under 1.0 %.

1.2 Units—With the exception of the values for density and the mass used to determine density, for which the use of the gram per cubic centimetre (g/cm³) and gram (g) units is the longstanding industry practice, the values stated in SI units are to be regarded as standard.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.