Methodology for testing the electrical parameters of low-voltage foil
Measuring capacitance
- Place the molded foil sample in a measuring cell with electrolyte in such a way that only the working part of the sample (without the terminal) is immersed in the electrolyte;
- Keep the sample for 1 minute, then measure the capacity;
- The capacitance value obtained from the device is divided by 10 to obtain the specific capacitance value in μF/dm2.
Methodology for testing electrical parameters of high-voltage foil
1.1 Forming etched foil samples for subsequent forming in electrolyte No. 4
1.2 Forming etched foil samples for subsequent forming in electrolyte No. 1
Hydration
- Time: 15±1 minute;
- Temperature: ≥ 95°C;
- Number of samples: ≤ 6;
- Replace deionized water: after each hydration process.
Forming electrolyte
Forming stage 1:
- Boric acid - 100 g;
- Deionized water (≤ 0.1 μS/cm) — 900 ml.
Forming stage 2:
- Boric acid - 100 g;
- Ammonium pentaborate, tetrahydrate — 0.7 g;
- Deionized water (≤ 0.1 μS/cm) — 900 ml;
Forming parameters
- Forming current - 0.5 A/sample;
- Electrolyte temperature is 90±2°С.
Forming parameters
The test sample should be immersed in the electrolyte so that the top of the measured sample is 10-15 mm below the surface of the solution.
Forming electrolyte
- Citric acid - 2 g;
- Deionized water (≤ 0.1 μS/cm) - 1000 ml;
- Electrolyte resistance at + 30ºС is 1000 ± 50 Ohm×cm.
Molding scheme
– Forming cycle F1 – 10 minutes;
– Rinse (P1) – 1 minute;
– Annealing from +510 to +530°C (O) – 2 minutes;
– Forming cycle (F2) – until the forming current drops to 0.03 A;
– Rinse (P2) – 1 minute.
Flushing
Samples are washed in deionized water at room temperature.
Drying
Drying of samples is carried out at a temperature of < 100°C.
2. Measuring forming stress
Test equipment
-
DC power supply
- ripple ≤ 1%;
- voltage stability ± 3%; - DC voltmeter - accuracy ± 0.5%;
- DC ammeter - accuracy ± 1.0%;
- Stainless steel bath, temperature control.
Electrolyte for voltage measurement
Forming voltage from 200V to 620V:
- Boric acid - 70g;
- Deionized water (≤ 0.1 μS/cm) - 1000 ml;
- Electrolyte conductivity at + 70ºС — 7,500 ± 300 Ohm×cm.
Forming voltage from 621V to 700V:
- Boric acid - 40g;
- Deionized water (≤ 0.1 μS/cm) - 1000 ml;
- Electrolyte conductivity at + 70ºС — 19,000 ± 1,000 Ohm×cm.
Forming voltage from 701V to 800V:
- Boric acid - 30g;
- Deionized water (≤ 0.1 μS/cm) - 1000 ml;
- Electrolyte conductivity at +70ºС — 28,900 ± 1,500 Ohm×cm.
Forming voltage above 800 V:
- Boric acid - 20g;
- Deionized water (≤ 0.1 μS/cm) - 1000 ml;
- Electrolyte conductivity at + 70ºС — 46,500 ± 2,500 Ohm×cm.
Measuring capacitance
- Place the molded foil sample in a measuring cell with electrolyte so that only the working part of the sample (without the terminal) is immersed in the electrolyte;
- Keep the sample for 1 minute, then measure the capacity;
- Multiply the capacitance value obtained from the device by 10 to obtain the specific capacitance value in μF/dm2.
4. Control of oxide layer stability
Electrolyte for voltage measurement
Forming voltage from 200V to 620V:
- Boric acid - 70g;
- Deionized water (≤ 0.1 μS/cm) - 1000 ml;
- Electrolyte conductivity at + 70ºС — 7,500 ± 300 Ohm×cm.
Forming voltage from 621V to 700V:
- Boric acid - 40g;
- Deionized water (≤ 0.1 μS/cm) - 1000 ml;
- Electrolyte conductivity at + 70ºС — 19,000 ± 1,000 Ohm×cm.
Forming voltage from 701V to 800V:
- Boric acid - 30g;
- Deionized water (≤ 0.1 μS/cm) - 1000 ml;
- Electrolyte conductivity at +70ºС — 28,900 ± 1,500 Ohm×cm.
Forming voltage above 800 V:
- Boric acid - 20g;
- Deionized water (≤ 0.1 μS/cm) - 1000 ml;
- Electrolyte conductivity at + 70ºС — 46,500 ± 2,500 Ohm×cm.
Methodology for testing the electrical parameters of cathode foil
Electrolyte for measuring capacity
- Ammonium adipate - 150 g;
- Deionized water (≤ 0.1 μS/cm) – 1000 ml;
- Сопротивление электролита, при + 70°С — 5,0 … 8,5 Ом×см.
Multiply the capacitance value obtained from the device by 20 to obtain the specific capacitance value in μF/dm2
Stabilization quality control
Electrolyte for measuring capacity
- Ammonium adipate - 150 g;
- Deionized water (≤ 0.1 μS/cm) – 1000 ml;
- Electrolyte resistance at + 70°C is 5.0 … 8.5 Ohm×cm.
Bending test method
Test conditions
Foil type | Bending radius, mm |
|---|---|
| Etched anode high voltage | 0,5 ± 0,05 |
| Molded anode low voltage | 0,5 ± 0,05 |
| Molded anode high voltage | 0,5 ± 0,05 |
| 3,5 ± 0,35 | |
| Cathodic etched | 1,0 ± 0,10 |
| Cathode annealed |