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GB/T 13390-2008 (GBT 13390-2008)

Chinese standards (related to): 'GB/T 13390-2008'
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GB/T 13390-2008English155 Add to Cart 0--3 minutes. Auto immediate delivery. Metallic powder -- Determination of the specific surface area -- Method of nitrogen adsorption GB/T 13390-2008 Valid GBT 13390-2008
GB/T 13390-1992English519 Add to Cart 4 days Metallic powder--Determination of the specific surface area--Method of nitrogen adsorption GB/T 13390-1992 Obsolete GBT 13390-1992


   
BASIC DATA
Standard ID GB/T 13390-2008 (GB/T13390-2008)
Description (Translated English) Metallic powder. Determination of the specific surface area. Method of nitrogen adsorption
Sector / Industry National Standard (Recommended)
Classification of Chinese Standard H16
Classification of International Standard 77.160
Word Count Estimation 12,153
Date of Issue 2008-03-31
Date of Implementation 2008-09-01
Older Standard (superseded by this standard) GB/T 13390-1992
Quoted Standard GB/T 5314
Drafting Organization CISRI
Administrative Organization National Nonferrous Metals Standardization Technical Committee
Regulation (derived from) National Standard Approval Announcement 2008 No.5 (Total No.118)
Proposing organization China Nonferrous Metals Industry Association
Issuing agency(ies) Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China; Standardization Administration of China
Summary This standard specifies the method for the determination of metal powder specific surface area. This standard applies to the determination of the specific surface area of ??metal powder. Measuring range: 0. 1m2/g ~ 1000m2/g. The specific surface area of ??non-metallic powders and porous materials can also be determined with reference to use. This standard specific surface area of ??the powder measured total surface area, including the nitrogen molecules can enter any opening powder body surface area, air permeation method which differs from the specific surface area determined, which means the surface area of ??the envelope.


GB/T 13390-2008: PDF in English (GBT 13390-2008)
GB/T 13390-2008
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.160
H 16
Replacing GB/T 13390-1992
Metallic powder - Determination of the specific surface
area - Method of nitrogen adsorption
ISSUED ON: MARCH 31, 2008
IMPLEMENTED ON: SEPTEMBER 01, 2008
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of the PRC;
Standardization Administration of the PRC.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Terms and symbols ... 4 
4 Principle ... 7 
5 Apparatus and materials ... 8 
6 Sampling ... 12 
7 Test procedure ... 12 
8 Calculation ... 13 
9 Test report ... 15 
Appendix A (Informative) Saturation vapour pressure of liquid nitrogen ... 16 
Metallic powder - Determination of the specific surface
area - Method of nitrogen adsorption
1 Scope
This Standard specifies the method for determination of the specific surface
area of metallic powder.
This Standard applies to the determination of the specific surface area of
metallic powder. The determination range is 0.1 m2/g~1000 m2/g. The
determination of the specific surface area of non-metallic powder and
microporous materials may also refer to it for use.
The specific surface area determined in this Standard is the total specific
surface area of the powder, including any open specific surface area where
nitrogen molecules can enter the powder body. It is different from the specific
surface area measured by the air permeation method, which refers to the
envelope surface area.
2 Normative references
The following documents contain provisions which, through reference in this
Standard, constitute provisions of this Standard. For the dated references, their
subsequent amendments (excluding corrections) or revisions do not apply to
this Standard. However, the parties who enter into agreement based on this
Standard are encouraged to investigate whether the latest editions of these
documents are applicable. For undated reference documents, the latest
editions apply to this Standard.
GB/T 5314 Powders for powder metallurgical purposes - Sampling
3 Terms and symbols
3.1 Terms
3.1.1
Adsorbate
The adsorbed gas enriched on the surface of the adsorbent.
3.1.2
Adsorbent
The powder that absorbs the measuring gas.
3.1.3
Equilibrium adsorption pressure
The pressure of the gas when the adsorbate reaches equilibrium.
3.1.4
Saturation vapour pressure
The vapour pressure when the adsorbate is completely liquefied at the
adsorption temperature.
3.1.5
Relative pressure
The ratio of equilibrium adsorption pressure to saturation vapour pressure.
3.1.6
Adsorption volume
The volume of gas adsorbed by the adsorbent at equilibrium adsorption
pressure.
3.1.7
Dead volume
The volume of the area where the adsorbate fails to reach under equilibrium
pressure.
3.2 Symbols
The symbols used in this Standard are shown in Table 1.
5.3.3 Liquid nitrogen or liquid oxygen; it shall have a certain degree of purity so
that its saturation vapour pressure remains stable during the measurement
process.
6 Sampling
6.1 Sampling shall be carried out in accordance with the provisions of GB/T
5314.
6.2 If the volumetric method is used, the sample shall be weighed so that its
total surface area is within the range of 5 m2~50 m2. If a continuous flow
chromatograph is used, the sample shall be weighed so that its total surface
area is within the range of 0.5 m2~200 m2.
7 Test procedure
7.1 Degassing
Before the adsorption measurement, the specimen must be degassed.
When measuring with a volumetric method tester, the specimen shall be heated
and degassed under vacuum. The vacuum degree is 1.33 Pa~1.33×10-2 Pa.
The heating temperature is 100°C~300°C. The holding time is 0.5 h~3 h.
When measuring with a continuous flow chromatograph, the specimen shall be
heated and rinsed under a flowing inert atmosphere. The heating temperature
is 100°C~300°C. The holding time is 0.5 h~3 h.
7.2 Measurement
7.2.1 Measurement by volumetric method
Let a known amount of adsorbed gas gradually enter the sample chamber (see
Figure 2). Each time the sample adsorbs gas, and therefore the gas pressure
in the limited constant volume drops, until the adsorption reaches equilibrium.
The amount of adsorbed gas is the difference BETWEEN the amount of gas
entering the burette AND the amount of gas remaining in the burette and the
sample holder after adsorption equilibrium. This amount is determined by the
gas state equation.
The dead volume must be determined before or after the adsorption isotherm
measurement. This volume is calibrated with helium at the measured
temperature.
7.2.2 Measurement by continuous flow chromatograph
Nitrogen is the adsorbed gas. Helium is the carrier gas (hydrogen can also be
used). After the two gases are mixed in a certain ratio, they flow through the
sample at close to atmospheric pressure. Use a thermal conductivity cell to
monitor the thermal conductivity of the mixed gas.
Adjust the helium flow rate to about 40 mL/min; use the soap bubble flowmeter
(14) to measure the helium flow rate RHe. Adjust the nitrogen flow rate. After the
two gases are evenly mixed, use the soap bubble flowmeter (14) to measure
the total flow rate RT of the mixed gas. Then turn on the power; adjust the zero
point of the bridge. After the apparatus is stable, put the Dewar flask filled with
liquid nitrogen on the sample tube (12). When the adsorption reaches
equilibrium, the thermal conductivity cell (9) detects an adsorption peak.
Remove the liquid nitrogen bath; the thermal conductivity cell (9) again detects
a desorption peak with the opposite polarity to the adsorption peak. Usually,
after the helium flow is adjusted, it will not be re-adjusted. By changing the
nitrogen flow rate 𝑅ேమ, change the relative pressure. Within the range of relative
pressure P/P0 of 0.05~0.30, at least 3~5 points must be measured.
After the desorption is completed, turn the six-way valve (10) to the calibration
position; inject a known volume of pure nitrogen into the mixed gas, to obtain a
standard peak. For instruments with instrument constants, there is no need
measuring standard peaks.
8 Calculation
8.1 Volumetric method
8.1.1 Dead volume correction factor
The dead volume correction factor ϕ is calculated by formula (7).
8.1.2 Amount of adsorbed gas filled
The amount of adsorbed gas filled is calculated by formula (8).
8.1.3 Amount of remaining adsorbed gas
When the adsorption reaches equilibrium, the amount of remaining adsorbed
gas is calculated by formula (9).
......