1 Scope
This standard specifies the determination method of specific surface area of metallic powder.
This standard is applicable to the determination of specific surface area of metallic powder, with the range of 0.1 m2/g to 1,000 m2/g. It may be used as reference for the determination of specific surface area of non-metallic powder and microporous materials.
The specific surface area measured in this standard is the total specific surface area of the powder, including any open pore specific surface area allowing nitrogen molecules to enter the powder body; it is different from the specific surface area measured by air permeation method, which refers to the envelope surface area.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this standard. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition applies.
GB/T 5314 Powders for powder metallurgical purposes—Sampling
3 Terms and symbols
3.1 Terms
3.1.1
adsorbate
adsorbed gas concentrating on the surface of the adsorbent
3.1.2
adsorbent
powder for adsorbing measuring gas
3.1.3
equilibrium adsorption pressure
pressure of the gas when the adsorbate reaches equilibrium
3.1.4
saturation vapour pressure
vapour pressure when the adsorbate is completely liquefied at the adsorption temperature
3.1.5
relative pressure
ratio of equilibrium adsorption pressure to saturation vapour pressure
3.1.6
adsorption volume
volume of gas adsorbed by the adsorbent under equilibrium adsorption pressure
3.1.7
dead volume
volume of adsorbate failing to reach the area under equilibrium pressure
Foreword i
1 Scope
2 Normative references
3 Terms and symbols
4 Principle
5 Apparatus and materials
6 Sampling
7 Procedures
8 Calculation
9 Test report
Annex A (Informative) Saturation vapour pressure of liquid nitrogen
