Determination method of artificial graphite lattice parameter
1 Scope
This standard specifies the principle, internal standard materials, instruments, specimen preparation, test conditions, test steps, processing and calculation of test results and test report for determination of artificial graphite lattice parameter by X-ray powder diffraction method (diffractometer method).
The method is applicable to artificial graphite with high graphitization degree after high temperature heat treatment (such as graphite for artificial diamond).
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections) to, 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.
JB/T 8133.1-1999 Test methods for physical-chemical properties of electric carbon products - Technical requirements for specimen processing
3 Principle
3.1 The graphitization degree of artificial graphite is a physical quantity and is usually measured by the size of the lattice parameter and expressed in the symbol PB.
3.2 The artificial graphite lattice parameter is defined in 3.2.1 to 3.2.4.
3.2.1 c0(002): The c-axis length of the artificial graphite unit cell obtained from C(002) diffracted ray.
3.2.2 c0(004): The c-axis length of the artificial graphite unit cell obtained from C(004) diffracted ray.
3.2.3 a0(110): The a-axis length of the artificial graphite unit cell obtained from C(110) diffracted ray.
3.2.4 d112: The interplanar spacing d of the artificial graphite unit cell (112) obtained from C(112) diffracted ray.
3.3 The C(002), C(004), C(110) and C(112) diffraction patterns are recorded by an automatic X-ray diffractometer, the corresponding diffraction angle 2θCs is calculated by chord midpoint method, the respective diffraction angle 2θCj is calculated by internal standard method, and the corresponding artificial graphite lattice parameters c0(002), c0(004), a0(110) and d112 are obtained from the table. In addition, the graphitization degree PB is calculated using an equation from the lattice parameter c0(004).
4 Internal standard materials
Monocrystalline silicon powder (spectroscopically pure). Grind it with an agate mortar, and take the silicon powder passing through the 325-mesh (45μm) standard sieve as the internal standard materials for X-ray diffraction.
5 Instruments
Automatic X-ray diffractometer, using Cu-target X-ray tube.
6 Specimen preparation
6.1 Sampling method and sample size are subject to product standards.
6.2 Wipe the surface of the artificial graphite test block to be tested with alcohol cotton.
6.3 Crush the artificial graphite test block to be tested into powder with a hacksaw blade (or steel file) and let the powder pass through a 200-mesh (76μm) standard sieve. Take this powder as the specimen, and grind it with an agate mortar in case of too coarse grains.
Foreword i
1 Scope
2 Normative references
3 Principle
4 Internal standard materials
5 Instruments
6 Specimen preparation
7 Test conditions
8 Test steps
9 Processing and calculation of test results
10 Test report
Annex A (Informative) Comparison between PB and g
Table 1 Slit system of X-ray diffractometer
Table 2 Diffracted ray index and diffraction angle of carbon and silicon internal standard
Table 3 Relationship between 2θC(002)j and c0(002) (CuKαm)
Table 4 Relationship between 2θC(004)j and c0(004) (CuKαm)
Table 5 Relationship between 2θC(110)j and a0(110) (CuKαm)
Table 6 Relationship between 2θC(112)j and d112 (CuKαm)
Table 7 Relationship between 2θC(002)j and c0(002) (CuKαi)
Table 8 Relationship between 2θC(004)j and c0(004) (CuKαi)
Table 9 Relationship between 2θC(110)j and a0(110) (CuKαi)
Table 10 Relationship between 2θC(112)j and d112 (CuKαi)
Table A.1 Comparison between PB and g
