Overview
ISO 22960:2008 specifies a validated chemical method for the determination of iron (Fe) in titanium and titanium alloys using molecular absorption spectrometry with 1,10‑phenanthroline. The procedure is applicable for iron mass fractions from 0.005 % to 2.0 % and is intended for routine laboratory analysis and quality control where accurate iron quantification in titanium materials is required.
Key topics and technical requirements
- Principle: Dissolve the test portion in hydrochloric and hydrofluoric acids, oxidize titanium with nitric acid, neutralize/complex with boric acid, then add tartaric acid, ammonium acetate and hydroxyl‑ammonium chloride. Form the 1,10‑phenanthroline–iron complex and measure absorbance by spectrophotometry.
- Analytical range: 0.005 % to 2.0 % Fe in titanium/titanium alloys.
- Reagents: HCl, HNO3, HF, boric acid, tartaric acid, ammonium acetate, hydroxyl‑ammonium chloride, 1,10‑phenanthroline, and certified iron standard solutions.
- Instrumentation: Spectrophotometer (measure at 510 nm using a 10 mm cell), Class A volumetric glassware, analytical balance (0.1 mg sensitivity).
- Calibration and quality control: Prepare a working curve from iron standard solutions (0–8 ml aliquots) with correlation better than 0.999. Perform a blank test and carry out determinations at least in duplicate.
- Sample prep and aliquots: Sample dissolution in HCl/HF with nitric oxidation, addition of boric acid, then dilution and aliquoting per recommended test portion sizes depending on anticipated Fe content.
- Precision: Method precision is defined by repeatability, within‑laboratory reproducibility and between‑laboratory reproducibility limits given as formulae in the standard (depend on the measured Fe mass fraction). Results are calculated and reported to three decimal places.
Applications and users
- Quality control laboratories in titanium production and downstream processing.
- Aerospace, medical device and automotive material testing where iron content affects mechanical properties and corrosion behavior.
- Metallurgical laboratories validating alloy composition and conformity to specifications.
- Certification and inspection bodies performing acceptance testing of titanium products.
This ISO method is valuable when a reliable, chemical spectrophotometric alternative to instrumental techniques (e.g., ICP-OES) is needed or when instrument availability is limited.
Related standards
Normative references in ISO 22960:2008 include ISO 384, ISO 648, ISO 1042, ISO 3696 and ISO 4787 (volumetric glassware, water for analytical use, and laboratory practice), which support accurate volumetric and analytical procedures required by the method.
Open preview (PDF)Titanium and titanium alloys — Determination of iron — Molecular absorption spectrometry using 1, 10-phenanthroline