Iron, steel and alloy — Determination of nickel content — Flame atomic absorption spectrometric method
WARNING - Persons using this document shall be familiar with normal laboratory practice. This document does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions.
1 Scope
This document specifies a method for the determination of nickel in steel and cast iron by means of flame atomic absorption spectrometry.
The method is applicable to nickel contents in the range 0.002% to 5.0% (m/m).
2 Normative references
The following documents contain provisions which, through reference in this text, constitute indispensable provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) 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 Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method (GB/T 6379.2-2004, ISO 5725-2: 1994, IDT)
GB/T 12805 Laboratory glassware — Burettes (GB/T 12805-2011, ISO 385: 2005, NEQ)
GB/T 12806 Laboratory glassware — One-mark volumetric flasks (GB/T 12806-2011, ISO 1042: 1998, NEQ)
GB/T 12808 Laboratory glassware — One-mark pipettes
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)
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3 Terms and definitions
No terms and definitions are listed in this standard.
4 Principle
Dissolution of a test portion in a mixture of appropriate acids followed by evaporation to fuming with perchloric acid. Spraying of the solution into an air-acetylene flame. Spectrometric measurement of the atomic absorption of the 232.0 nm or 352.5 nm spectral line emitted by a nickel hollow cathode lamp.
Note: With some instruments, it is not possible to obtain sufficient sensitivity at the wavelength of 352.5 nm for low concentrations of nickel near the bottom end of the application range and, in such cases the alternative wavelength of 232.0 nm may be used.
At the wavelength of 352.5 nm, the signal-to-noise ratio is higher than at a wavelength of 232.0 nm. In general, use of the 352.5 nm line will give better reproducibility.
5 Reagents or materials
During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and having a very low nickel content and only distilled water or water of equivalent purity. If possible, use only freshly prepared distilled or deionized water.
5.1 Iron of high purity
Nickel content < 0.0005% (m/m).
5.2 Hydrochloric acid-nitric acid mixture
Mix three parts by volume of hydrochloric acid (p about 1.19 g/mL), one part by volume of nitric acid (p about 1.42 g/mL), and two parts by volume of water. Prepare this mixture immediately before use.
Foreword i
Introduction iv
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Reagents or materials
6 Apparatus
7 Sampling
8 Procedure
9 Expression of results
10 Test report
Annex A (Informative) Components of the GB/T
Annex B (Normative) Steps for determining the instrument criteria
Annex C (Informative) Additional information on the precision tests
Annex D (Informative) Graphical representation of precision data
