This standard specifies the particle size, particle size and composition, impurity content, inspection method, marking and packaging of artificial diamond micropowder and cubic boron nitride micropowder. This standard applies to micropowders made of artificial diamond and cubic boron nitride synthesized by static pressure method. JB/T 7990-1998 Superhard abrasive artificial diamond micropowder and cubic boron nitride micropowder JB/T7990-1998 Standard download decompression password: www.bzxz.net

JB/T7990—1998
This standard is based on the rapid development of the domestic superabrasive industry. The output of artificial diamond micropowder and cubic boron nitride micropowder is increasing, and the export volume has increased significantly. In order to make the standard in line with international standards as soon as possible, JB/T7990.1~7990.4--95 (formerly GB6966.16966.5--86) is revised. The important difference between this standard and JB/T7990.1~~7990.4--95 is that this standard uses an advanced particle image processor instead of a biological microscope; the particle size is characterized by the equivalent projected area diameter. This standard non-equivalently adopts the American national standard ANSIB74.20-1981 "Grain Size Classification of Diamond Micropowder". There are slight changes in technical content and editing, and corresponding specifications are added according to market conditions. Appendix A and Appendix B of this standard are both prompt appendices. This standard shall replace JB/T7990.1~7990.4-95 from the date of implementation. This standard is proposed and managed by the National Technical Committee for Standardization of Abrasives and Grinding Tools. The drafting units of this standard are: Zhengzhou Abrasives and Grinding Research Institute, Wuhan 9301 Factory of the General Logistics Department. The main drafters of this standard are: Huang Xiangfen, Liu Changsheng, Pei Liqun. Scope
Machinery Industry Standard of the People's Republic of China
Superhard abrasives
Artificial diamond micropowder and cubic boron nitride micropowder JB/T7990—1998
Replace JB/T7990.17990.4--95
This standard specifies the particle size, particle size and composition, impurity content, inspection method, marking and packaging of artificial diamond micropowder and cubic boron nitride micropowder.
This standard is applicable to micropowders made of artificial diamond and cubic boron nitride synthesized by static pressure method. 2 Reference Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T6405-94 Varieties of artificial diamond and cubic boron nitride JB3914--85 Sampling method for superhard abrasives
JB/T7994-95 Chemical analysis method for cubic boron nitride 3 Definitions
This standard adopts the following definitions:
Micropowder particle size - a particle group divided by the Stokes method or special method according to a certain particle size range; Particle size
Coarse particles -
Fine particles -
The diameter of a circle equivalent to the outer area of ​​the particle measured under a microscope (equivalent projected area diameter) D; Particles exceeding the upper limit of the nominal size to the maximum size of the coarse particles; - Particles smaller than the lower limit of the nominal size to the minimum size of the fine particles; Finest particles -\ - Particles smaller than the minimum size of the fine particles; Needle-rod particles -.- Needle-shaped or rod-shaped particles with a ratio of the major axis to the minor axis exceeding 3/1; Flake particles - - Flake particles that are transparent when observed through light under a microscope. 4 Particle size and size range
4.1 Particle size marking
Particle size marking is marked with the upper and lower limits of each particle size range (separated by a slash) and preceded by "M\" (see Table 1). 4.2 Size range and particle size composition
The size range and particle size composition of each particle size shall comply with the provisions of Table 1. Approved by the State Machinery Industry Bureau on July 17, 1998 38
Implementation from December to January 1, 1998
Particle size marking
M10/20
M12/22wwW.bzxz.Net
M20/30
M22/36
M36/54
5 Shape and impurity requirements
5.1 Needle-rod granules
Nominal size range
10～20
12~-22
20~-30
22～36
36~~ 54
JB/T 7990--1998
Maximum size of coarse particles
Minimum size of fine particles
Particle size group
1. There shall be no particles larger than
maximum size of coarse particles.
2. The content of coarse particles shall not exceed 3%.
3. Content of fine particles: The particle size of M3/6 and above shall not exceed 8%; M4/8 to
M10/20 shall not exceed 18%; M12/
22 to M36/ 54 Not more than 28%.
4. Finest particle content: All particle sizes do not exceed 2%
The micro powder should not contain any needle-shaped particles whose length exceeds twice the maximum size of the coarse particles; it may contain needle-shaped particles whose length is between the maximum nominal size and twice the maximum size of the coarse particles, but it shall not exceed 3%. 5.2 Flake particles
Flake particles in diamond micro powder shall not exceed 5%, and flake particles in cubic nitride micro powder shall not exceed 10%, and the fine particles are not counted.
5.3 The impurity content of diamond micropowder of various particle sizes shall not exceed 2%, and the impurity content of cubic boron nitride micropowder shall not exceed 5% (both by weight). 6 Inspection
6.1 Particle size composition inspection
6.1.1 Sampling
Mix the micropowder thoroughly and evenly, then divide it into four equal parts in the material cup with a glass rod, take out the required amount from each equal part and mix them together for chemical analysis or film preparation inspection. Sampling shall be carried out in accordance with the provisions of JB3914 during arbitration. 6.1.2 Equipment and instruments
With magnification up to PIP6.0 particle image processor with at least 1500 times biological microscope or other instruments with accuracy and performance not less than this instrument (biological microscope, projection microscope, electron microscope, etc.). 6.1.3 Determination method
Place the sample on the end of the slide, drip an appropriate amount of glycerol, mix it with a glass rod, and then dip a little on the sample according to the "cross" method, place it in the middle of the slide, drip a small amount of glycerol to adjust the hook, cover it with a clean glass cover and press it tightly, taking care to prevent the glycerol from squeezing out, and then place it under the microscope for observation. If the particle distribution is uniform, the measurement can be started. Otherwise, the sample should be re-made. The recommended magnification is shown in Table 2. 39
Particle size mark
M3/6 and above
M4/8 to M8/12
M8/16 to M12/22
M12/22 to M36/54
JB/T 7990—1998
Imager objective lens
Minimum magnification of microscope
1600×
When measuring the particle size, the particles in each field of view should be measured in sequence from one end of the sample to the other, and at least 500 particles should be measured cumulatively. If the edges of the particles are found to be in contact with each other, the image can be scratched; the images of particles where two or more particles overlap or are obviously not diamond or cubic boron nitride phases can be erased. Then measure and calculate, and print the results. The format of the test report is shown in Appendix A (suggestive appendix).
When inspecting with a biological microscope, refer to Appendix B (suggestive appendix). During arbitration inspection, use a particle image processor to inspect 3 samples, and measure no less than 1500 particles in total. 6.2 Impurity inspection method
6.2.1 Diamond micropowder impurity inspection method
The impurities in diamond micropowder refer to the non-combustible substances existing in the material to be tested after the combustible impurities are removed by chemical treatment. 6.2.1.1 Equipment and tools
Muffle furnace above 1000°C, 1/10,000 analytical balance, ceramic quartz crystal. 6.2.1.2 Determination method
Use the combustion weight loss method to determine the impurities in the micropowder. Take samples according to regulations and weigh 0.2g of the sample to be tested, put it in a constant weight crucible: place it in a muffle furnace and heat it to constant weight (temperature is allowed to be +20°C), the weight of the residue is the impurity amount, and the weight percentage is calculated. Each batch of samples must be inspected for the finest particle size product. If the number is unqualified, it shall be inspected from fine to coarse until the qualified particle size number is reached. 6.2.2 Inspection method for impurities in cubic boron nitride powder The impurities in cubic boron nitride powder refer to the non-cubic boron nitride powder in the cubic boron nitride powder. 6.2.2.1 Inspection method
Inspect in accordance with the provisions of JB/T7994.
6.2.2.2 Calculation of impurity content
Assume that the sample to be tested is 100%, and its impurity content is equal to this value and the value of the cubic boron nitride content obtained by measuring the sample, that is: impurity content = 1-CBN%
7 Marking and packaging
7.1 Marking
7.1.1 The packaging must be clearly marked with: trademark, factory name, variety, particle size mark, weight and batch number, and be accompanied by a certificate of conformity. 7.1.2 The certificate of conformity shall indicate: type, particle size mark, batch number, packaging date, and inspector (stamp). 7.2 Packaging
7.2.1 The product is packed in double-layer plastic bags, and the certificate of conformity is placed between the two layers. 7.2.2 The product is packed in 1g, 2g, 5g, 10g, 20g, 50g, 100g, 200g, 500g, 1000g, etc. 7.2.3 The packaging should be beautiful and ensure convenient and safe transportation. 40
Test report format:
Sample name: Diamond M5/10
Sample delivery unit: Diamond Micro Powder Factory of our companyEquivalent principle: Equal area circle
Number of particlesAverage particle size: 6.72μm
Characteristic particle size:
D10:5.9 μm
D50:7.1 μm
Ratio of long and short diameters:
Differential distribution
Batch number: 709095
JB/T 7990-1998
Appendix A
(Suggested Appendix)
Test Report Format
Test Report
Sample Delivery Time: 97-06-27
Total Number of Particles: 509
Distribution Statistics Unit: Volume
Volume Average Particle Size: 7.21μm
D90: 8.7 μm
Number of Particles Greater Than 2: 9
Cumulative Distribution
Particle Size Distribution Curve
Particle Size Distribution Table
Differential Distribution
Objective Lens Magnification: X40
Specific Surface Area: 1.38m/cc
Number of Particles Greater Than 3: 1
Cumulative Distribution
Testing Unit
Tester:
Test time:
Differential distribution
Cumulative distribution
Test report format II:
Sample name: Diamond M5/10
Sample delivery unit: Diamond micro powder factory of our companyEquivalent principle: Equal area circle
Number of particlesAverage particle size: 6.72um
Ratio of long and short diameter:
Batch number: 709095
JB/T 7990—1998
Test report
Sample delivery time: 97-06-27
Total number of particles: 509
Distribution statistical unit: volume
Volume average particle size: 7.21μum
Number of particles larger than 2: 9
Objective lens magnification: ×40
Specific surface area: 1.38m*/cc
Number of particles larger than 3: 1
Cumulative distribution details
Test unit
Tester
Test time
JB/T 7990—1998
Appendix B
(Suggestive Appendix)
Comparison of Particle Projection Width and Equivalent Projection Area Diameter When the micro powder projection width is tested by microscope, the test results are compared with the test results of particle image processing instrument, as shown in Table B1. Table B1
Nominal size range
Particle size marking
M10/20
M12/22
M20/30
M22/36
M36/54
Similar circle diameter
0. 5 ~1. 5
8～16
10~~20
20～30
22-~36
Particle width
0. 4~～1. 2
1. 1~1. 6
1.2~-2. 3
1. 9~3. 9
4. 7~ 9.3
6.2～12. 4
9. 3 - 17. 1
15. 5~23. 3
17. 1 ~ 27. 9
27.9--41.9
Maximum particle size
Minimum fine particle size
0.5 to fine 0.4 to fine
[0.5 to fine 0.4 to fine
[0.5 to fine 0.4 to fine
i1. Meaning of BD
Because (d/2)AB, when A
1. 32B, D = (1. 27 ×
1.32B213, so D/
Where: A—particle projection length
particle equivalent projection
shadow area diameter.
2. Content of each particle group according to particle percentage
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