GB/T 24514-2009 English PDF (GBT24514-2009)

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GB/T 24514-2009: Zinc and/or aluminium based coating on steel -- Determination of coating mass per unit area and chemical composition -- Gravimetry, inductively coupled plasma atomic emission spectrometry and flame atomic absorption spectrometry
GB/T 24514-2009
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 25.220.40
H 11
Zinc and/or aluminium based coating on steel -
Determination of coating mass per unit area and chemical
composition - Gravimetry, inductively coupled plasma
atomic emission spectrometry and flame atomic absorption
spectrometry
(ISO 17925:2004, MOD)
ISSUED ON: OCTOBER 30, 2009
IMPLEMENTED ON: MAY 01, 2010
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of the People's Republic of China;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword ... 3 
1 Scope ... 5 
2 Normative references ... 5 
3 Principle ... 6 
4 Reagents and materials ... 7 
5 Apparatus ... 10 
5.1 General ... 10 
5.2 Inductively coupled plasma atomic emission spectrometer (APE-APE) ... 10 
5.3 Flame atomic absorption spectrometer (FAA) ... 11 
5.4 Platinum crucible ... 12 
6 Sampling and specimen ... 12 
7 Determination steps ... 12 
7.1 Specimen preparation ... 12 
7.2 Procedure for the determination of mass per unit area ... 12 
7.3 Steps of determination of chemical composition by inductively coupled plasma atomic
emission spectrometry ... 14 
7.4 Steps of determination of chemical composition by flame atomic absorption
spectrometry ... 17 
8 Representation of results ... 20 
8.1 Representation of mass per unit area results ... 20 
8.2 Representation of chemical composition results ... 21 
9 Test report ... 24 
Annex A (informative) Analyte content in the coating ... 24 
Annex B (informative) Additional explanation for international cooperative tests ... 26 
Annex C (informative) Graphical representation of precision data ... 29 
Annex D (informative) Comparison on chapter numbers and titles between this
Standard and the international standard ISO 17925:2004 ... 34 
Zinc and/or aluminium based coating on steel -
Determination of coating mass per unit area and chemical
composition - Gravimetry, inductively coupled plasma
atomic emission spectrometry and flame atomic absorption
spectrometry
1 Scope
This document specifies the method of gravimetry method to determine the coating
mass per unit area, as well as the methods of inductively coupled plasma atomic
emission spectrometry and flame atomic absorption spectrometry to determine
chemical composition of zinc-based and/or aluminum-based single-sided coatings on
steel surfaces.
The zinc-based and/or aluminum-based coatings on the steel surface described in this
Standard include hot-dip and electro-pure zinc coating, hot-dip galvanized iron alloy
coating, electro-galvanized nickel alloy coating, hot-dip galvanized aluminum coating
(5% of aluminum) and hot-dip galvanized aluminum coating (55% of aluminum). The
chemical composition of zinc-based and/or aluminum-based coatings on steels
described in this Standard includes the chemical composition of iron, aluminum in hot-
dip galvanized coatings, zinc, iron and aluminum in alloyed coatings, zinc, iron, nickel
in electro-galvanized nickel coating, hot-dip galvanized aluminum coating (5% of
aluminum), and zinc, iron, aluminium and silicon in hot-dip Al-Zn coating (55% of Al).
The applicable measurement range of this Standard is 40%~100% for zinc content
(mass fraction), 0.02%~60% for aluminum content (mass fraction), 7%~20% for nickel
content (mass fraction), 0.2%~20% for iron content (mass fraction) and 0.2%~10% for
silicon content (mass fraction).
The method for determining the chemical composition of coatings by flame atomic
absorption spectrometry (FAAS) is not applicable to the determination of zinc content.
The determination method of this Standard can be used as an arbitration method.
2 Normative references
The provisions in following documents become the provisions of this Standard through
reference in this Standard. For dated references, the subsequent amendments (excluding
corrigendum) or revisions do not apply to this Standard, however, parties who reach an
agreement based on this Standard are encouraged to study if the latest versions of these
documents are applicable. For undated references, the latest edition of the referenced
document applies.
GB/T 6379.1, Accuracy (trueness and precision) of measurement methods and
results - Part 1: General principles and definitions (GB/T 6379.1-2004, ISO 5725-
1:1994, IDT)
GB/T 6379.2, Measurement methods and results - Accuracy (trueness and precision)
- Part 2: Determine the standard methods of measurement repeatability and
reproducibility of the basic method (GB/T 6379.2-2004, ISO 5725-2:1994, IDT)
GB/T 6682, Water for analytical laboratory use - Specification and test methods
(GB/T 6682-2008, ISO 3696:1987, MOD)
GB/T 12806, Laboratory glassware - One-mark volumetric flasks (GB/T 12806-
1991, neq ISO 1042:1983)
GB/T 12808, Laboratory glassware - One mark pipettes (GB/T 12808-1991, neq
ISO 648:1977)
GB/T 20066, Steel and iron - Sampling and preparation of samples for the
determination of chemical composition (GB/T 20066-2006, ISO 14284:1996, IDT)
ISO 5725-3, Accuracy (trueness and precision) of measurement methods and results
- Part 3: Intermediate measures of the precision of a standard measurement method
3 Principle
Use a hydrochloric acid solution containing a corrosion inhibitor to peel off the coating
on one side of the steel surface (the role of the corrosion inhibitor is to prevent
hydrochloric acid from corroding the steel substrate). Respectively determine the mass
of the specimen before and after peeling of the coating. Divide the mass difference by
the surface area of the specimen to obtain the coating mass per unit area.
Remove the coating on the measurement surface of the specimen with a stripping
solution. Dilute, filter and set constant volume the solution. Use an inductively coupled
plasma atomic emission spectrometer (ICP-AES) or a flame atomic absorption
spectrometer (FAAS) to determine. Divide the content of the element to be measured
by the mass of the coating measured in advance to obtain the chemical composition of
the element in the coating.
Table 1 lists the analytical lines and interfering elements for each element. Other
analytical lines can also be selected according to the performance of the spectrometer
used in the laboratory.
stripping solution (4.8), stop-off material protects the non-measured surface coating. It
does not contaminate the acid solution. At the same time, the mass is not increased or
decreased, so as to avoid the influence on the mass of the coating and the determination
of the chemical composition.
Usually acid-resistant paint, paint or acid-resistant tape is used as stop-off material. It
is also possible to use a mechanical device to fasten the specimen to achieve one-sided
closure.
4.10 Zinc standard stock solution: 1000mg/L
Weigh 0.500g of high-purity zinc (mass fraction is not less than 99.99%), accurate to
0.0005g. Dissolve it in 25mL of hydrochloric acid (4.1). After cooling, transfer the
solution to a 500mL volumetric flask. Use water to dilute to the scale. Mix well.
4.11 Zinc standard solution A: 100mg/L
Pipette 100mL of zinc standard stock solution (4.10) into a 1000mL volumetric flask.
Add 10mL of hydrochloric acid (4.1). Use water to dilute to the scale. Mix well.
4.12 Zinc standard solution B: 10mg/L
Pipette 100mL of zinc standard solution A (4.11) into a 1000mL volumetric flask. Add
10mL of hydroc...