This standard specifies the use of breakdown potential to test the insulation of aluminum and aluminum alloy anodized films. This standard is applicable to the testing of the insulation performance of anodized films, and mainly tests the following two types of anodized films: a. Anodized films with certain requirements for insulation performance. B. Anodized films produced by anodizing processes formulated based on the breakdown potential principle. GB/T 8754-1988 Aluminum and aluminum alloy anodizing - Testing insulation by breakdown potential determination method GB/T8754-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Anodizing of alunthium and aluminium alloys--- Insulation check by feasurementof breakdown potential
This standard specifies the use of breakdown potential to check the insulation of anodized films on aluminium and aluminium alloys. UDC669.718.915
:621.317.3
GB 87 5 4 -bzxz.net
ISO 2376—· 72
This standard is applicable to the inspection of the insulation properties of anodized films, mainly the following two types of anodized films: a. Anodized films with certain requirements for insulation properties. b. Anodized films produced by anodizing processes formulated based on the principle of breakdown potential. In general, this standard is only used to inspect anodized films after sealing and drying, and is not applicable to the inspection of oxide films coated with paint or with other covering layers.
This standard is equivalent to ISO2376--1972 "Anodizing (anodizing) of aluminum and aluminum alloys - Application of breakdown potential determination method to test insulation".
1 Principle of the method
The principle of breakdown potential measurement is based on the dielectric properties and insulation properties of the oxide film. The measured voltage refers to the voltage value when the current passes through the oxide film instantly. The magnitude of the breakdown voltage depends on the thickness of the oxide film and many other factors, among which the more important ones are: surface state, composition of the base metal, sealing effect, dryness and aging of the workpiece. 2 Device
The test device can choose various instruments that can continuously change the AC voltage. The sensitivity of the voltage reading is 10V, and the power supply frequency is 50Hz and 60Hz.
The following are two commonly used test electrode systems, namely: a. Single electrode system: one ball electrode is in contact with the surface to be tested (the diameter of the ball is 3~~8mm); the other electrode is fixedly connected to the base metal.
b. Double electrode system: Two metal balls of the same diameter are used as two electrodes, and the two electrodes form a test system between points 25 mm apart (the diameter of the ball is 3 to 8 mm). In both cases, the metal balls must be clean. A force between 0.5 and 1N must be applied to the metal balls. The voltage increase rate is 25V/s.
3 Test steps
3.1 The instrument should be operated according to the instructions. 3.2 It should be noted that when the two electrodes are placed on a smooth or processed test piece, they should be several centimeters apart. They can also be placed on a curved surface with a radius of curvature greater than 5 mm, but they should be more than 5 mm away from the sharp angle or edge. 3.3 For narrow specimens, the test should be carried out on the long axis. However, the electrode should be at least 1 mm away from the corner. 3.4 Record the voltage when the oxide film is electrically broken down. Repeat the measurement 10 times at various locations on the specimen, and then calculate the arithmetic mean of the breakdown voltage. China National Nonferrous Metals Industry Corporation Approved on February 4, 1988, and implemented on February 1, 1989
Nesting means
GB8754-88
The breakdown potential of the film is the arithmetic mean of the measurements at 10 different test points on the specimen, which is regarded as the breakdown potential value. 4.1
If the single-electrode measurement method is used, the measured result is the breakdown potential value of the film. 4.2
If the double-electrode measurement method is used, the measured result is roughly twice the breakdown potential value of the film. Additional notes:
This standard was drafted by Northeast Light Alloy Processing Plant. The main drafters of this standard are Gao Kangzhi and Wang Ziyi. 380
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