GB/T 17848-2026 Test methods for electrochemical properties of sacrificial anodes English, Anglais, Englisch, Inglés, えいご
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ICS 13.220.10
CCS H 57
National Standard of the People's Republic of China
GB/T 17848-2026
Replaces GB/T 17848-1999
Test methods for electrochemical properties of sacrificial anodes
牺牲阳极电化学性能试验方
Issue date: 2026-01-28 Implementation date: 2027-02-01
Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
the Standardization Administration of the People's Republic of China
Contents
Foreword
1 Scope
2 Normative References
3 Terms and Definitions
4 Classification of Test Methods
5 Test Apparatus
6 Preparation of Anode Test Specimens
7 Test Conditions
8 Test Procedure
9 Representation of Test Results
10 Test Report
Annex A (Informative) Preparation Method for Copper Coulometer
Annex B (Informative) Preparation Method for Artificial Seawater
Electrochemical Performance Test Methods for Sacrificial Anodes
1 Scope
This document specifies the test apparatus, specimen preparation, test conditions, test procedures, representation of test results, and precautions for testing the electrochemical performance of sacrificial anodes using the conventional test method, accelerated test method, and long-term test method.
This document is applicable for testing the electrochemical performance of zinc alloy, aluminum alloy, and magnesium alloy sacrificial anodes in seawater, and for testing the electrochemical performance of magnesium alloy sacrificial anodes in simulated soil. The testing of electrochemical performance of sacrificial anodes in other media may refer to this document.
2 Normative References
The following documents contain provisions which, through normative reference in this text, constitute essential provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.
GB/T 33373 Corrosion Protection — Electrochemical Protection — Terminology
3 Terms and Definitions
For the purposes of this document, the terms and definitions given in GB/T 33373 and the following apply.
3.1
practical current capacity
The quantity of electricity actually measured to be generated per unit mass of sacrificial anode consumed.
3.2
theoretical current capacity
The quantity of electricity calculated according to Faraday's law to be generated per unit mass of sacrificial anode consumed.
3.3
current efficiency
The ratio of the practical current capacity of a sacrificial anode to its theoretical current capacity.
3.4
open circuit potential
The potential of a sacrificial anode measured relative to a reference electrode when no current is flowing.
3.5
working potential
The potential of a sacrificial anode when protective current is flowing.
NOTE: Also known as closed circuit potential.
4 Classification of Test Methods
4.1 Conventional Test Method
Within a specified test period, a constant current is applied to the anode test specimen. The working potential of the anode test specimen is measured daily. After the test, the practical current capacity and current efficiency of the anode test specimen are calculated, and the dissolution pattern of the anode test specimen is observed.
4.2 Accelerated Test Method
Within a specified test period, the current density applied to the anode test specimen is changed sequentially according to a schedule. The working potential of the anode test specimen is measured daily. After the test, the practical current capacity and current efficiency of the anode test specimen are calculated, and the dissolution pattern of the anode test specimen is observed.
4.3 Long-Term Test Method
Within a specified test period, the test is conducted using self-discharge or by applying a constant current to the anode test specimen. The working potential of the anode test specimen is measured according to the required testing frequency. After the test, the practical current capacity and current efficiency of the anode test specimen are calculated, and the dissolution pattern of the anode test specimen is observed.
5 Test Apparatus
5.1 Schematic Diagram of Test Apparatus
The electrochemical performance test apparatus for sacrificial anodes mainly consists of an auxiliary cathode, a test container, a variable resistor, a DC ammeter, a coulometer, a power supply, a DC voltmeter, a reference electrode, and the anode test specimen. If temperature or pressure control is required, temperature control or pressure control equipment should be added externally to the test container. A schematic diagram of the test apparatus is shown in Figure 1.
5.2 Auxiliary Cathode
The auxiliary cathode should preferably be a cylinder made of stainless steel, with both the inner and outer surfaces serving as working surfaces. The ratio of the cathode cylinder area to the anode test specimen working area shall be not less than 30.
5.3 Test Container
For the conventional test method and accelerated test method, the volume of the test container shall not be less than 5 L. The anode test specimen and the auxiliary cathode shall be completely immersed in the test medium. For the long-term test method, specimens should be placed in a test container capable of maintaining continuous flow and replacement of seawater (at least 1 L/min). The test container should preferably be made of materials with stable performance, such as fiberglass-reinforced plastic.
5.4 Variable Resistor
A decade resistor should be used, with a resistance value preferably not less than 11.11 kΩ.
5.5 DC Ammeter
A milliammeter with an accuracy class higher than 0.5 should be used.
5.6 Power Supply
For the conventional test method and accelerated test method, a DC power supply with a rated output current not less than 60 mA and an output voltage not less than 40 V shall be used. For the long-term test method, a DC power supply with a rated output current not less than 500 mA and an output voltage not less than 60 V shall be used.
NOTE: If a constant current source with an error of 0.1% is used, the variable resistor, DC ammeter, and coulometer are not required.
5.7 Coulometer
The quantity of electricity can be measured using a copper coulometer, an electronic coulometer, or real-time current integration via software. The preparation method for a copper coulometer is given in Annex A. The accuracy of an electronic coulometer or other device capable of automatically recording the quantity of electricity shall not be less than 0.5% of the full scale.
5.8 DC Voltmeter
A digital voltmeter with an input impedance greater than 10 MΩ and a minimum scale division of 1 mV or higher, or a high-precision potentiometer, shall be used.
5.9 Reference Electrode
A saturated calomel electrode or a silver/silver chloride electrode/saturated potassium chloride shall be used.
5.10 Anode Test Specimen
Anode test specimens shall be prepared according to the specified preparation requirements.
6 Preparation of Anode Test Specimens
6.1 For the conventional test method and accelerated test method, the anode test specimens shall be machined into a cylindrical rod shape. Specimens with specifications shown in Figure 2 may be used, with a diameter of 16 mm ± 1 mm and a length of 48 mm ± 3 mm. Specimens shall be prepared by machining. An M4 hole shall be drilled and tapped on the end face of the specimen for connecting a conductive metal rod. At least 3 specimens are required for each test group.
6.2 For the long-term test method, the anode test specimens shall be machined into a cylindrical rod shape, with a diameter of at least 25 mm ± 1 mm and a length of at least 100 mm ± 5 mm. Specimens with specifications shown in Figure 3 may be used. Specimens shall be prepared by machining. An M4 hole shall be drilled and tapped on the end of the specimen for connecting a conductive metal rod. At least 5 specimens are required for each test group. For the constant current method, the recommended anode specimen diameter is 110 mm and length is 150 mm. For the self-discharge method, the recommended anode specimen diameter is 50 mm and length is 120 mm.
6.3 Clean the anode test specimen with distilled water, then remove oil and grease using absolute ethanol or acetone.
6.4 Place in an oven and dry at 105°C ± 2°C for 30 minutes. Remove and place in a desiccator.
6.5 After the anode test specimen cools to room temperature, perform the first weighing. Then repeat the drying and weighing procedure. The difference between two consecutive weighing results shall not be greater than 0.4 mg. The average of the two weighings shall be taken as the mass of the anode test specimen. If the difference between the two weighings is greater than 0.4 mg, a third drying and weighing shall be performed, and the average of the two closest weighing results shall be taken as the mass. An analytical balance with a minimum scale division of 0.1 mg shall be used for weighing.
