GB/T 3137-1995 Test method for electrical properties of tantalum powder
Some standard content:
National Standard of the People's Republic of China
Testing method of electrical property of tantalum powders
Subject content and scope of application
GB/T 3137.--1995
G313782
This standard specifies the principle, instruments and equipment, materials, sample preparation, test conditions and calculation of test results for the test method of electrical properties of tantalum powders.
This standard is applicable to the test of electrical properties of tantalum powders for capacitors. 2 Principle of the method
Tantalum powders are formed and sintered into capacitor anode blocks, and the blocks are left in phosphoric acid electrolyte for anodization to form an anodized film with a unidirectional conductive property with a certain dielectric constant on its surface. This oxide film is used as a dielectric in capacitors. The bad blocks after anodization are covered in the measuring solution electrolyte, the oxidized bad blocks are connected to the positive electrode, the metal in contact with the electrolyte is the negative electrode, and connected to the measuring instrument, the current, capacity and loss value can be measured.
3 Instruments and equipment
3.1 Instruments
3.1.1 Balance sensitivity dry fraction -→
Vacuum measuring instrument
3.1.3 Optical pyrometer.
3.1.4 Universal ammeter 1.5 level.
Capacitance bridge.
Current tester.
3.1.7 Stopwatch,
3.2 Equipment
Hydraulic press 2~51.
Crimping core mold 6.0~~3.0mm, wipe it clean with white silk cloth before use. 3. 2. 2
3.2.3 Vacuum sintering furnace:
Tungsten wire furnace. Humidity 2500, vacuum not less than 0.013Pa; molybdenum sheet furnace, temperature 2400C, vacuum not less than 0.00665Pa. Leakage rate is not more than 0.4μml/s.
3.2.4 Spot welding machine, 2~~5kW, electrode head is tungsten and molybdenum material 3.2.5
Rectifier juice, control energizing table, silver tank. Electric oven 0~~200℃ blast.
State Technical Supervision Bureau approved 19960301 on October 17, 1995 for implementation
4 Materials
4.1 Phosphoric acid (pl.69g/ml.).
Sulfuric acid (pl.84 g/mL)
Deionized water resistivity 3Ma·cm.
Molybdenum wire d0.6 (or 0.5) mm.
Molybdenum crucible:
Test cup.
Glass test tube $8.0~12.0 mm.
Sample preparation
GB/T 3137—1995
For each batch of samples, weigh 10 to 12 required powder samples and put them into a clean glass tube. The weight of each sample is as specified in Table 1. Table 1
Working voltage, V
Weight + g
5.2 Molding
25, 35
5.2.1 Various series of molybdenum powder samples are molded under appropriate molding pressure, so that the molded bad block falls from a height of 5 cm into the glass container [L without breaking.
5.2.2 The insertion depth of the silver wire is about half of the molybdenum block, and the bad block shall not have missing edges and cracks. 5.2.3 The molding density is calculated according to formula (1):
Wherein: D molding density.g/cm\;
bad block weight, g;
V-bad block volume, cm;
pi;
bad block radius, cm
-bad block height, cm.
5.3 Sintering
5.3.1 Put the molded molybdenum block into the molten metal, then stack it on the crucible and put it into the high temperature zone of the furnace. 5.3.2 After the furnace is evacuated to 0.00532Pa, leak detection is carried out. When the leak detection result meets the requirements, it can be powered on and the temperature can be raised. The sintering conditions are as specified in Table 2.
Product brand
FTa16-300
FTa16-260
FTa16-220
FTal6-200
Working voltage
Sintering conditions
1500/20
1500/30
1550/20
1550/20
Product brand
FTa25-180
FTa25-150
FTa25 120
FTa35-100
FTa35-80
FTa40-60
FTa40-45
FTa40-42
FTa40-35
FTa50-40
FTa5 0-35
FTa63-35
FTa63-30
FTa63-28
FTa63-25
FTa63-20
FTa63-15
FTa63-10
GB/T 3137--1995
Continued Table 2
Working voltage
5.3.4 Temperature measurement: The observation mirror is transparent and clean, without any stains. The observation conditions should be as close to the black body conditions as possible. 5.3.5 After the insulation is completed, cut off the current, cool for 60 minutes, stop the diffusion pump, and then take it out of the furnace after another 60 minutes. 5.4 Spot welding
5.4.1 Spot weld in rows according to 5 pieces. During the spot welding process, sparks must not be struck to damage or contaminate the tantalum block. 5.5 Energization
The energization conditions shall be as specified in Table 3.
Working voltage V
Bin energy solution
Energizing temperature, C
Energizing voltage, V
Constant voltage time, min
Current density, mA/g
Diluted solution
0. 01%H,PO.
0. 01%H.PO
Sintering conditions
1 600/36Www.bzxZ.net
1600/30
1 600/30
1700/30
1700/30
1750/30
1800/30
1900/30
1900 /30
1900730
1900/30
1900/30
1950/30
2050/30
2050/30
2050/30
2050/30
2050/30
2050/30
0.01%HP)
35mA/g rise to 200V. Then
drop to 12mA/g. Then rise to
GB/T3137--1995
5.5.2Put the spot-welded molybdenum block into the silver tank, add the energizing solution, and immerse the block completely. Connect the molybdenum block to the negative pole of the power supply, and the silver tank to the negative pole of the power supply. The two shall not touch each other.
5.5.3During the energizing process, add diluent frequently to keep the liquid level unchanged. 5.5.4Dry the energized tantalum anode block in an oven at 85C for 30min. 6 Test conditions and steps
Measurement conditions shall be as specified in Table 1.
Leakage current
Capacitor loss
Working voltage
Voltage, V
Time, min
Temperature, C
DC voltage, V
AC voltage, V
Frequency, Hz
0. 01 %HPO
38%HS0
0. 5~1. 0
O. OIVIPO
38%H,S0
0. 5 ~1. 0
(. C1%H,P0
0.5-~1. 0
6.2 When measuring the leakage current of the cover, the depth of the anode block immersed in the solution is about two-thirds of its height, so that the solution can spread to the upper end surface of the button block. When measuring capacity and loss, the anode block is completely immersed in the solution, and the chucks are in good contact. 6.3 Reading
Expression of test results
Specific capacitance is calculated according to formula (2):
Where: weight specific capacitance.μF.V/g;
actual measured capacity of anode, μF;
energizing voltage, V;
bad block weight +.
7.2 Leakage current (K value) is calculated according to formula (3): K
Wu Zhong: K-
Leakage current K value μA/μF.V
actual measured leakage current of anode·pA:
C—-actual measured capacity of anode block,uF;
Energizing voltage, V.
7.3 Breakdown voltage (see Appendix A)
7.4 The results are reported as average values.
·(2)
Test report
The test report shall include the following contents:
Report number;
Test date;
Brand, batch number and specification;
Test report;
Test personnel;
This standard number.
GB/T 3137-1995
A1 Subject content and scope of application
GB/T 3137--1995
Appendix A
Test method for breakdown voltage of molybdenum powder
(reference)
This method specifies the principle, instrument and equipment, test steps and result processing of the powder breakdown voltage test method. This method is applicable to the detection of molybdenum powder breakdown voltage. A2 Principle of the method
Button powder is pressed and sintered into a button anode. During the formation of the anodic oxide film, the constant current density is increased. As the voltage increases, the oxide film gradually thickens, and the electronic current component gradually increases until an electron avalanche occurs, the anodic oxide film breaks down, the current suddenly rises, and the voltage drops. The voltage value at this time is called the anode breakdown voltage.
A3 Instruments and equipment
A3.1 Instruments
A3.1.1 XY function recorder
A3.1.2 Leiji 27 conductivity meter
A3.2 Equipment
A3.2.1 DC power supply: rated current 1A. A3.2.2 Temperature-controlled heating electric furnace
A3.2.3 1000mL covered energizing tank (or beaker with 1000mL scale). A3.3 Others
Test steps
A4.1 Spot weld the anodes prepared by the sample to be tested on the molybdenum bar in groups of 3 and lead them out with leads. A4.2 Add 700mL of 0.01% HPO4 aqueous solution into the energizing tank. The pure water resistivity of the prepared solution is greater than 3MQ·cm. 0.01% H,PO, aqueous solution has a resistivity of about 2750-30002·cm. A4.3 Clamp the anode block and immerse it in the energizing tank, with the upper end of the molybdenum block 4-5mm below the liquid surface. A4.4 Connect the positive end of the DC power supply to the molybdenum anode block, and the negative end to the epithelial cathode. A4.5 Heat the solution to 85°C, start the DC power supply, and boost the voltage to near the anode energizing voltage specified in the molybdenum powder standard (soil 10V) as specified in Table A1, stop boosting, and remove the molybdenum block for measurement. Table Al
Working voltage
Temperature,
Current density, mA/g
Anode block weight basis·g
0. 01%H.PO4
0. 01%H:PO,
0. 01%H:PO
GB/T 3137
A4.6Replace the solution before each measurement, and do not replace the solution until all three tubes are measured. For each measurement, the voltage is still increased according to the specified current density, and the voltage recorder is connected until breakdown. The recorder records the point where the voltage suddenly drops as the breakdown voltage. A5 Result processing
The measurement results are reported as the average value.
Additional remarks:
This standard is proposed by China Nonferrous Metals Industry Corporation. This standard is under the jurisdiction of the Standard Metrology Institute of China Nonferrous Metals Industry Corporation. This standard is drafted by Zhuzhou Cemented Carbide Guanghe Ningxia Nonferrous Metals Smelter. The main drafters of this standard are Wang Zhaoxin, Zhang Jingfang, Yu Jiangling, Huang Lieru and Shi Fulin.
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