GB/T 4949-2026 Chemical analysis methods for sacrificial anode of Al-Zn-In system alloy 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 4949-2026
Replaces GB/T 4949-2018
Chemical analysis methods for sacrificial anode of Al-Zn-In system alloy
铝-锌-铟系合金牺牲阳极化学分析方法
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
Introduction
1 Scope
2 Normative References
3 Terms and Definitions
4 Determination of Zinc Content — Na₂EDTA Titrimetric Method and Flame Atomic Absorption Spectrometric Method
5 Determination of Indium Content — Flame Atomic Absorption Spectrometric Method
6 Determination of Cadmium Content — Flame Atomic Absorption Spectrometric Method
7 Determination of Tin Content — Pyrocatechol Violet - Cetyltrimethylammonium Bromide Micellar Solubilization Spectrophotometric Method
8 Determination of Magnesium Content — Flame Atomic Absorption Spectrometric Method and Na₂EDTA Titrimetric Method
9 Determination of Silicon Content — Ammonium Oxalate - Ammonium Ferrous Sulfate Silicon Molybdenum Blue Spectrophotometric Method
10 Determination of Titanium Content — Dianipyrylmethane Spectrophotometric Method
11 Determination of Iron Content — 1,10-Phenanthroline Spectrophotometric Method and Flame Atomic Absorption Spectrometric Method
12 Determination of Copper Content — Flame Atomic Absorption Spectrometric Method and Sodium Diethyldithiocarbamate - Trichloromethane Extraction Spectrophotometric Method
13 Determination of Lead Content — Graphite Furnace Atomic Absorption Spectrometric Method
14 Determination of Zinc, Indium, Cadmium, Tin, Magnesium, Silicon, Titanium, Iron, Copper, and Lead Content — Inductively Coupled Plasma Atomic Emission Spectrometric Method
15 Determination of Zinc, Indium, Cadmium, Tin, Magnesium, Silicon, Titanium, Iron, and Copper Content — Spark Source Atomic Emission Spectrometric Method
16 Test Report
Appendix A (Informative) Example of Result Correction for Spark Source Atomic Emission Spectrometry
Methods for Chemical Analysis of Aluminum-Zinc-Indium Series Alloy Sacrificial Anodes
1 Scope
This document specifies methods for the determination of zinc, indium, cadmium, tin, magnesium, silicon, titanium, iron, copper, and lead content in aluminum-zinc-indium series alloy sacrificial anodes.
This document applies to the determination of zinc, indium, cadmium, tin, magnesium, silicon, titanium, iron, copper, and lead content in aluminum-zinc-indium series alloy sacrificial anodes. The determination ranges are shown in Table 1.
2 Normative References
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 6682 Water for analytical laboratory use – Specification and test methods
GB/T 8170 Rules for rounding off of numerical values and expression and judgement of limiting values
GB/T 14203 General rules for spark discharge atomic emission spectrometry
JJG 768 Verification Regulation of Emission Spectrometer
3 Terms and Definitions
For the purposes of this document, the terms and definitions given in GB/T 14203 and the following apply.
3.1
standardization sample
A homogeneous sample used for performing standardization correction.
Note: The standardization sample should at least cover the high and low content ranges of the calibration curve for each element. The number of standardization samples should be as few as possible to minimize standardization time.
[Source: GB/T 14203-2016, 3.13, modified]
3.2
control sample
A homogeneous sample with a structure similar to the analysis sample, having a similar chemical composition and accurately assigned values, which can be used for type standardization correction.
[Source: GB/T 14203-2016, 3.15, modified]
3.3
global standardization
A method of correcting the full range of the original calibration curves for multiple analytical programs on the same matrix by measuring the element intensities from standardization samples.
[Source: GB/T 14203-2016, 3.14]
3.4
type standardization
A method of correcting a limited region of the original calibration curve by measuring the element intensities from a control sample.
[Source: GB/T 14203-2016, 3.16]
3.5
calibration curve
An equation or functional curve representing the relationship between the content of an element in a sample and the intensity of light emitted by that element as measured by the instrument.
[Source: GB/T 14203-2016, 3.11]
4 Determination of Zinc Content — Na₂EDTA Titrimetric Method and Flame Atomic Absorption Spectrometric Method
4.1 Na₂EDTA Titrimetric Method
4.1.1 Principle
The test portion is dissolved with hydrochloric acid and hydrogen peroxide. In a hydrochloric acid medium, zinc(II) forms a complex with thiocyanate, which is quantitatively extracted into 4-methyl-2-pentanone. The zinc(II) is then back-extracted into the aqueous phase using a hexamethylenetetramine buffer solution and titrated with a standard volumetric solution of disodium ethylenediaminetetraacetate (Na₂EDTA).
4.1.2 Reagents
4.1.2.1 Unless otherwise stated, use only reagents of analytical grade and distilled or deionized water or water of equivalent purity during the analysis. The water used for analysis shall at least meet the requirements of grade 2 water as specified in GB/T 6682.
4.1.2.2 Hydrochloric acid (ρ = 1.19 g/mL).
4.1.2.3 Hydrogen peroxide (ρ = 1.11 g/mL).
4.1.2.4 4-methyl-2-pentanone (ρ = 0.80 g/mL).
4.1.2.5 Hydrochloric acid (1+1).
4.1.2.6 Thiourea solution (20 g/L).
4.1.2.7 Ammonium thiocyanate solution (500 g/L).
4.1.2.8 Ammonium fluoride solution (50 g/L), store in a plastic bottle.
4.1.2.9 Ammonium thiocyanate wash solution (50 g/L): Take 50 mL of ammonium thiocyanate solution (4.1.2.7), add 10 mL of hydrochloric acid (4.1.2.5), dilute with water to 500 mL, and mix.
4.1.2.10 Hexamethylenetetramine buffer solution (pH 5.8): Weigh 100 g of hexamethylenetetramine, dissolve in water, transfer to a 500 mL volumetric flask, add 20 mL of hydrochloric acid (4.1.2.2), dilute to the mark with water, and mix.
4.1.2.11 Zinc standard solution (0.0150 mol/L): Weigh 0.4903 g of pure zinc (zinc mass fraction not less than 99.99%) into a 200 mL beaker. Add a total of 40 mL of hydrochloric acid (4.1.2.5) in two portions. When the reaction slows, heat to complete dissolution. After dissolution is complete, cool to room temperature, transfer to a 500 mL volumetric flask, dilute to the mark with water, and mix.
4.1.2.12 Standard volumetric solution of disodium ethylenediaminetetraacetate (Na₂EDTA), prepare as follows.
a) Preparation: Weigh 3.72 g of Na₂EDTA, dissolve in water, transfer to a 1000 mL volumetric flask, dilute to the mark with water, and mix.
b) Standardization: Pipette 15.00 mL of the zinc standard solution (4.1.2.11) into a 250 mL conical flask. Add approximately 30 mL of water and 20 mL of the hexamethylenetetramine buffer solution (4.1.2.10). Add 1 to 2 drops of xylenol orange solution (4.1.2.13). Titrate with the Na₂EDTA standard volumetric solution [4.1.2.12 a)] until the color of the solution changes from purplish-red to pure yellow (the endpoint). Record the volume of Na₂EDTA standard volumetric solution consumed.
c) Calculation: Calculate the concentration of the Na₂EDTA standard volumetric solution according to formula (1):
[Formula would be shown here in a formal document]
Carry out the standardization on 3 portions. The range of the volumes of zinc standard solution consumed should not exceed 0.10 mL. Take the average value; otherwise, re-standardize.
4.1.2.13 Xylenol orange solution (2 g/L).
4.1.3 Test Sample
Prepare the test sample by drilling, milling, or turning. The thickness of the sample should not exceed 1 mm.
4.1.4 Analysis Procedure
4.1.4.1 Test Portion
Weigh 1.00 g of the test sample, accurate to 0.1 mg.
4.1.4.2 Duplicate Test
Carry out the determination independently twice and take the average value.
4.1.4.3 Determination
