GB/T 8754-2022 English PDF (GBT8754-2022)

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GB/T 8754-2022: Anodic oxidation coatings and organic polymer coatings on aluminium and aluminium alloys - Determination of electrical insulation
GB/T 8754-2022
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 25.220.20
CCS H 20
Replace GB/T 8754-2006
Anodic oxidation coatings and organic polymer coatings on
aluminium and aluminium alloys -- Determination of
electrical insulation
ISSUED ON: MARCH 9, 2022
IMPLEMENTED ON: OCTOBER 1, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
Introduction ... 5
1 Scope ... 7
2 Normative references ... 7
3 Terms and Definitions ... 7
4 Method overview ... 8
5 Test conditions ... 8
6 Instruments and equipment ... 8
7 Samples ... 13
8 Test steps ... 13
9 Result calculation and presentation ... 16
10 Test report... 17
Introduction
Anodic oxide films and organic polymer films on aluminum and aluminum alloys are
mainly used as the protection and decoration for aluminum and aluminum alloy surfaces,
and are widely used in many fields such as transportation, construction, furniture, home
appliances, decoration, food packaging, mechanical parts, and functional materials.
GB/T 8754 “Anodic oxidation coating and organic polymer coatings on aluminium and
aluminium alloys -- Determination of electrical insulation” specifies the method for the
determination of insulating properties of anodic oxide films and organic polymer films
on aluminum and aluminum alloys.
The following standards together constitute the standard system that supports
performance requirements and testing methods for anodic oxide films and organic
polymer films on aluminum and aluminum alloys.
GB/T 8754 Anodic oxidation coatings and organic polymer coatings on aluminium
and aluminium alloys -- Determination of electrical insulation
GB/T 12967.1 Test methods for anodic oxidation coatings and organic polymer
coatings of aluminium and aluminium alloys -- Part 1: Measurement of abrasion
resistance
GB/T 12967.3 Test methods for anodic oxidation coatings and organic polymer
coatings on aluminium and aluminium alloys -- Part 3: Salt spray test
GB/T 12967.4 Test methods for anodic oxidation coatings and organic polymer
coatings on aluminium and aluminium alloys -- Part 4: Determination of ultraviolet
light and heat resistance
GB/T 12967.5 Test methods for anodic oxidation coatings and organic polymer
coatings on aluminium and aluminium alloys -- Part 5: Assessment of resistance to
cracking
GB/T 12967.6 Test methods for anodic oxidation coatings and organic polymer
coatings on aluminium and aluminium alloys -- Part 6: Determination of color and
appearance
GB/T 8014.1 Anodizing of aluminium and its alloys -- The measuring method of
thickness of anodic oxide coatings -- Part 1: The measuring principle
GB/T 8014.2 Anodizing of aluminium and its alloys -- The measuring method of
thickness of anodic oxide coatings -- Part 2: Mass-loss method
GB/T 8014.3 Anodizing of aluminium and its alloys -- The measuring method of
thickness of anodic oxide coatings -- Part 3: Split-beam microscope method
GB/T 8752 Anodizing of aluminium and its alloys -- Check of continuity of thin
anodic oxide coating -- Copper sulphate test
GB/T 8753.1 Anodizing of aluminium and its alloys -- Assessment of quality of
sealed anodic oxidation coatings -- Part 1: Measurement of the loss of mass after
immersion in acid solution(s)
GB/T 8753.3 Anodizing of aluminium and aluminium alloys -- Assessment of
quality of sealed anodic oxide coatings -- Part 3: Admittance test
GB/T 8753.4 Anodizing of aluminium and aluminium alloys -- Assessment of
quality of sealed anodic oxide coatings -- Part 4: Dye spot test with prior acid
treatment
GB/T 20503 Anodizing of aluminium and its alloys -- Measurement of specular
reflectance and specular gloss
GB/T 20504 Anodizing of aluminium and its alloys -- Visual determination of
image clarity of anodic oxidation coatings -- Chart scale method
GB/T 20505 Anodizing of aluminium and its alloys -- Measurement of reflectance
characteristics of aluminium surfaces using integrating-sphere instruments
In 1988, our country formulated GB/T 8754-1988 “Anodizing of aluminium and
aluminium alloys -- Insulation check by measurement of breakdown potential” for the
first time by identically adopting ISO 2376:1972 “Anodization (anodic oxidation) of
aluminium and its alloys -- Insulation check by measurement of breakdown potential”.
In 2006, our country issued GB/T 8754-2006 “Anodizing of aluminium and its alloy --
Insulation check by measurement of breakdown potential” by modifying ISO
2376:1972 “Anodization (anodic oxidation) of aluminium and its alloys -- Insulation
check by measurement of breakdown potential”, used GB/T 8754-2006 to replace GB/T
8754-1988, added the scope of application of the method, refined the test procedures,
and added the content of the test report. In recent years, anodic oxide films and organic
polymer films made by various surface film preparation techniques have been widely
used in aluminum alloy products, and insulating films have also been extended from
anodic oxide films to organic polymer films. There is a broad prospect for development,
and the existing standards cannot meet the evaluation requirements of the insulation
properties of different types of films, so it is necessary to specify the insulation
performance evaluation methods of different types of films in GB/T 8754.
This revision focuses on the addition of methods for the determination of insulation
properties of round wires and organic polymer films.
3.2 Breakdown voltage
When a voltage is applied at a constant incremental rate, the minimum voltage that
causes the film to lose its dielectric properties and become a conductor.
3.3 Breakdown Strength
The value obtained by dividing the breakdown voltage by the thickness of the film on
the sample.
3.4 Electrical insulation
The general term for the withstand voltage impact capability of the insulating film,
which is expressed by breakdown voltage, breakdown strength, and withstand voltage.
4 Method overview
Apply an AC voltage at a constant incremental rate to the film or between the film and
the substrate until the voltage suddenly drops, then measure the breakdown voltage of
the film. Or apply an AC voltage at a constant incremental rate to the film or between
the film and the substrate until the specified test voltage is reached. If the voltage can
be kept constant for a specified time, then the test voltage can be evaluated as the
withstand voltage.
Note: The breakdown voltage and withstand voltage are related to the dielectric properties and insulating
properties of the film, and the breakdown voltage and the withstand voltage depend on the thickness of
the film and other factors, such as the composition of the substrate, the surface state, the sealing state of
the oxide film, the degree of aging of the oxide film, the degree of dryness, and the humidity of the test
environment.
5 Test conditions
The temperature of the test environment shall be 23 °C±2 °C, and the relative humidity
shall be not higher than 65%.
6 Instruments and equipment
6.1 High voltage equipment
The high-voltage equipment consists of transformers, circuit breakers, high-voltage test
voltage regulators, current-limiting resistors, voltmeters, etc. The frequency of the
power supply shall be 50 Hz or 60 Hz. The schematic diagram of the circuit is shown
in Figure 1. The requirements for high-voltage equipment are as follows:
othe...