ASTM B923

Measurement Protocol

High precision measurements depend on maintaining a constant temperature during the test. Samples undergo a degas process to remove adsorbed moisture and volatile organics before the gas is introduced. The instrument measures the pressure drop when gas expands from the reference cell to the sample chamber.

Solid volumes are determined from these pressure ratios.

Powder Suitability

Sintered materials with closed internal pores may yield lower density values than expected. The technique fails to penetrate sealed cavities, meaning it measures only the skeletal volume accessible to the helium. Fine powders require careful handling to prevent them from entering the gas manifold during expansion cycles.

Protective filters or slower gas introduction rates protect the instrument.

Sourcing Impact

Sourcing contracts for nickel or cobalt powders frequently specify minimum density thresholds determined by this method. Buyers require high density to ensure the powder packs tightly during electrode manufacturing. Inconsistent skeletal density points to variations in the material synthesis process.