This standard is applicable to the measurement of the phase content in polycrystalline powder of metal materials. It can also be used as a reference for quantitative phase analysis of polycrystalline powder samples of other materials. GB/T 5225-1985 Quantitative Phase Analysis of Metallic Materials X-ray Diffraction K Value Method GB/T5225-1985 Standard Download Decompression Password: www.bzxz.net

National Standard of the People's Republic of China
Quantitative phase analysis of metal materials
X-ray diffraction K value method
Metal materials--Quantitative phase analysis\Value K\ method of X - ray diffractionUDC 56s :520
GB 5223 --85
This standard is applicable to the measurement of the content of phases in polycrystalline powders of metal materials. It can also be used as a reference for quantitative phase analysis of polycrystalline powder samples of other materials.
The X-ray diffraction pattern of a phase is a characterization of the crystal structure characteristics of the phase. When the K value method is used to conduct quantitative X-ray diffraction analysis on multiphase samples, the cumulative intensity of the diffraction line of a phase is related to the content of the phase in the sample by formula (1) and (2) (see Appendix A for derivation): 1la(hikili)
K?Ir(hikit)\W
Tachikili)Wr
IF(hkti)
wherein:
Ta(hikili)-
Ir(hikit)
a(hikiti)
TF(hikit)
u is the weight content of the phase in the powder to be tested;
is a proportional constant. For the same radiation, this constant is related to the a phase to be measured and the reference material; the cumulative intensity of the diffraction line of the a phase (hiili) crystal plane when the reference material shield is not added to the powder to be measured; the cumulative intensity of the diffraction line of the reference material (hth) crystal plane after the reference material is not added to the powder to be measured; the cumulative intensity of the diffraction line of the a phase (hili) crystal plane in the reference sample; the cumulative intensity of the diffraction line of the reference material (h) crystal plane in the reference sample; the weight of the reference material after the reference material is not added to the powder to be measured; the weight of the powder to be measured when the reference material is added to the powder to be measured; the weight of the reference material in the reference sample:
the weight of the powder of the phase to be measured in the reference sample. The characteristic of this method is to first determine the K value and then determine X. Note: The reference sample refers to the sample prepared when the K value is determined. 2 Requirements and preparation of samples
2.1 Sample preparation
2.1.1 Weighing
When weighing the sample, the relative deviation of the weight shall not be greater than 0.1%. 2.1.2 Reference materials and reference samples
2.1.2.1 Selection of reference materials
The principles for selecting reference materials are:
a: During the test, its physical and chemical properties are stable and not easy to deliquesce: National Bureau of Standards 1985-07-18 Issued
1986-07-01 Implementation
GB5225-85
b: The intensity of the diffraction line measured by the test should be strong, and its peak position should be close to the measured diffraction line of the phase to be tested, but not overlapped, and not disturbed by other diffraction lines;
The linear absorption coefficient and particle radius of the reference material should be as close as possible to those of the phase to be tested. The particle radius should meet the requirements of 2.1.2.2 of this standard.c.

The linear absorption coefficient and particle radius of the reference material and the phase to be measured should satisfy the formula (3): 2.1.2.22
Where: u
Linear absorption coefficient of the phase to be measured, 1/cm; wwW.bzxz.Net
Linear absorption coefficient of the mixture of the reference material and the phase to be measured; D particle diameter, μm.
The allowable range of particle radius of the reference material and the phase to be measured is 0.1～50um. 2.1.2.3When calculating the K value, the recommended ratio of the reference sample formed by mixing the pure reference material and the pure phase to be measured is: WE
(3)
When the cumulative intensity of the diffraction lines of the reference material and the phase to be measured differs greatly, the ratio should be changed to enhance the cumulative intensity of the weak diffraction lines. 2.1.2.4The amount of reference material added to the powder to be measured should make the cumulative intensity of the diffraction lines selected by the phase to be measured and the reference material in the mixed sample basically equivalent.
Note: Mixed sample refers to the sample made by adding reference material to the powder to be tested. 2.1.3 Powder to be tested and mixed sample
2.1.3.1 During the whole determination process, the powder to be tested and the mixed sample must not undergo phase change, deliquesce, and have stable chemical properties. 2.1.3.2 The particle radius of the powder to be tested should meet the requirements of 2.1.2.2. 2.1.4 Mixed sample
Grind the powders prepared in 2.1.2.3 and 2.1.2.4 in an agate mortar for 30~40 minutes and mix them evenly. 2.2 Sample preparation
2.2.1 Size and thickness of reference sample and mixed sample At any selected diffraction position, the irradiation area of ​​X-rays shall not exceed the surface range of the sample. The thickness of the sample should satisfy the formula (4):
Where: t-the thickness of the sample, cm;
9the grazing angle, degrees;
-the linear absorption coefficient of the sample, 1/cm;
othe density of the mixed powder calculated according to the International Table of Physical Constants, g/cm3; o
the measured density of the mixed powder, g/cm2.
(4)
2.2.2 Sample preparation
2.2.2.1Use a commonly used sample frame and place a metallographic sandpaper of about 300 larger than the frame under the frame (or a correspondingly coarse frosted glass can also be used).
2.2.2.2Pour the ground mixed powder into the sample frame and press it vertically into shape. Turn the pressed sample over 180°, remove the sandpaper, and use the surface of the sample in contact with the sandpaper (or frosted glass) as the test surface. 2.2.2.3
Test instruments and test conditions
3.1 Diffractometer
The comprehensive stability of the diffractometer is better than 1%.
3.2 Test conditions
3.2.1 Scanning speed
GB5225—85
It is appropriate to select 0.5 degrees per minute or 0.25 degrees per minute. 3.2.2 Time constant
It is appropriate to select 2s or 4s accordingly.
3.3 Diffraction peak shape requirements
The peak height should be greater than 4 times the background fluctuation amplitude; the peak height should be about 4 times the half-height width.
Test steps and result calculation
Before making quantitative measurements, the diffraction line intensity of the reference sample and the mixed sample should be checked with the JCPDS standard card to check whether the reference material and the phase to be tested have preferential orientation. If there is a preferred orientation, the sample should be re-prepared to improve or eliminate the preferred orientation as much as possible. If the preferred orientation is not serious, it should be repaired according to Appendix B.
4.1 Determination of K value of reference sample
4.1.1 The pure phase to be tested for K value shall be subjected to qualitative analysis by X-ray diffraction to check its purity. No impurity diffraction lines shall appear. 4.1.2 The pure reference material selected according to 2.1.2 shall be checked for purity according to 4.1.1. 4.1.3 Prepare samples according to 2.1.1 and 2.1.2 respectively. 4.1.4 Prepare samples according to 2.1.4 and 2.2.
4.1.5 Record the cumulative intensity of each selected diffraction line. 4.1.6 Each sample shall be re-sampled at least three times, and the cumulative intensity of the diffraction lines shall be measured three times for each sample. Substitute the cumulative intensity value of each diffraction line into formula (2) to calculate the K value for each time, and take the average K value. The relative standard deviation (-1) of each measurement data is required to be equivalent to the comprehensive stability of the instrument. -1 is calculated according to formula (5): (-Yi)
× 100%
Where: y
The average value of a measurement result:
Yi is the i-th measurement result,
is the number of measurements.
4.1.7 Calculate the K value according to formula (2).
4.2 Determination of the content of the phase to be measured
4.2.1 Add reference material to the powder to be measured according to 2.1.2.4, and prepare the sample according to 2.2.2 so that the diffraction lines selected by the phase to be measured meet 3.3.
4.2.2 Record the cumulative intensity of each corresponding diffraction line according to 4.1.6. 4.2.3 Substitute the K value determined in 4.1.7 and the result of 4.2.2 into formula (1) to calculate the percentage content Xa of the phase to be measured. 4.3 If the above requirements are met, the relative deviation of Xa is 5%. * The instrument stability of this standard refers to the relative standard deviation of the diffraction line intensity value measured for 8 hours at a 10-min interval for the same diffraction plane of the sample under the same test conditions -1277
A.1 Derivation of formula (1) in this standard
GB 5225--85
Appendix A
(Supplement)
The cumulative intensity of the diffraction line of the powder can be expressed as 1
32 R
-C.A3.GV
.23.N2.IF12-
32 yuan R
where:
R—goniometer radius;
mass of electron,
charge of electron;
speed of light:
N—number of unit cells per unit volume;
λ—wavelength;
I. ——-ray intensity;
F-structure amplitude;
—multiplicity factor,
—grazing angle;
1 +cos220
sin2Acrs9
Lorentz—polarization factor;
Debye-Wallow factor,
absorption factor:
—volume of the irradiated part.
1+cOs22A
sin?cost
1+cos226
sin2gcos
For mixed samples, suppose r is the reference substance, and when all conditions remain unchanged, the cumulative intensity ratio of diffraction lines between phase a and reference substance r is: Ia- Ca3GVa.- Ga, Wa/Pa.-.
I,\CA3GV
Formula: density of phase a;
—-density of reference substance;
W weight of reference substance r;
W a-—-weight of phase a;
la cumulative intensity of diffraction lines of phase a after the reference substance is added to the powder to be tested; /—-cumulative intensity of diffraction lines of the reference substance after the reference substance is added to the powder to be tested. Ga/Pa
Then formula (A4) can be transformed into
The above formula is the standard formula (2).
Before adding the reference substance, the weight content X of the Q phase in the powder to be tested is 278
·(A6)
The weight of the powder to be tested.
武t:Wo-
GB5225-85
Substitute formula (A7) into formula (A6) and rearrange it to obtain Xa=
The above formula is the standard formula (1).
A.2 The significance of K value
Since it is a physical constant related to the properties of the a phase to be tested and the reference substance itself, the selected diffraction and the selected radiation, when the selected radiation is certain, its value is a proportional constant for the specified diffraction crystal plane of the two substances.
GB5225—85
Appendix B
(Supplement)
B.1 If the preferred orientation is not serious, the following formula can be used to correct the cumulative intensity of the diffraction line: I(hikili)=
o*(hikiti)
Where:
I(hikili)
It(hikili)
p*(hikili)
2 Nhikilt)/(hikili)
Tu(hikito)
It(hikiti)
N(hikiti).-
Tu(hikit)
The cumulative intensity of diffraction lines on the (hikiti) crystal plane after correction for preferred orientation: (B1)
It(h;kili), Tt(hikill)——The cumulative intensity of diffraction lines on the (hikili) crystal plane when there is preferred orientation; p*(hikil:)
Orientation probability density (pole density) of the (hihiti) crystal plane; N(hikili), N(hi kili)
lu(hikili),lu(hikit)
the multiplicity factor of (hikili), (hkll) crystal planes; —the cumulative intensity of diffraction lines of (hikili), (hkll) crystal planes when there is no preferred orientation (the relative intensity of diffraction lines given by the JCPDS-card can also be used; —the number of diffraction crystal planes selected.
B2 In order to obtain satisfactory correction results, the average orientation rate density value is required to conform to the formula o*(hikiti)
t: m
[Nhikili)p* (hikito)
Nhikit)
the number of diffraction crystal planes selected, mn.
This standard requires that the p* value be in the range of 0.95~1.05. Additional remarks:
This standard was proposed by the Ministry of Metallurgical Industry of the People's Republic of China. This standard was drafted by Beijing Iron and Steel Research Institute and other units. (B3)
The main drafters of this standard are Lu Jinsheng, Jin Xuecai, Xie Xiqing, Chen Hongye, Sha Jun, Qin Daoxiang, Gao Xiujuan, Yang Chengli and Sun Jingui. 28005. Additional remarks:
This standard was proposed by the Ministry of Metallurgical Industry of the People's Republic of China. This standard was drafted by Beijing Iron and Steel Research Institute and other units. (B3)
The main drafters of this standard are Lu Jinsheng, Jin Xuecai, Xie Xiqing, Chen Hongye, Sha Jun, Qin Daoxiang, Gao Xiujuan, Yang Chengli and Sun Jingui. 28005. Additional remarks:
This standard was proposed by the Ministry of Metallurgical Industry of the People's Republic of China. This standard was drafted by Beijing Iron and Steel Research Institute and other units. (B3)
The main drafters of this standard are Lu Jinsheng, Jin Xuecai, Xie Xiqing, Chen Hongye, Sha Jun, Qin Daoxiang, Gao Xiujuan, Yang Chengli and Sun Jingui. 280
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