EN 15022 Copper and Copper Alloys - Determination of Tin Content

The European standard, “EN 15022 Copper and copper alloys - Determination of tin content”, consists of the following sub-sections published under the same title:

The standard “EN 15022-1 Part 1: Titrimetric method” has not yet been published.
The standard “EN 15022-2 Part 2: Spectrophotometric method” describes a spectrophotometric method for determining the tin content of copper and copper alloys in raw, processed, and cast forms. This method is applicable to products with tin mass percentages between 0,005% and 0,5% (low to medium tin levels). This standard is based on the principle of extraction to methyl isobutyl ketone and spectrophotometric determination of the yellow tin-quercetin complex at a wavelength of 440 nm.

This method determines the tin content in copper and copper alloys and is applicable to the following products:

Unprocessed products (e.g., ingots).
Processed products (e.g., bars, sheets, pipes).
Cast products.

Tin is an important alloying element in bronzes (copper-tin alloys), phosphor bronzes, and brass, improving strength, corrosion resistance, and wear properties.

Spectrophotometric approaches include the following:

For example, dissolving it in a suitable acid mixture (typically hydrochloric acid and possibly other acids to completely dissolve the alloy).
Reducing tin to a specific oxidation state.
Forming a colored complex with tin using a reagent (typically phenylfluorone or similar compounds that produce a measurable color with tin ions).
Measuring the absorbance of a colored solution at a specific wavelength using a spectrophotometer.
To determine the tin content, the absorbance is compared with calibration curves prepared from standard tin solutions.

This method is sensitive and accurate for low tin concentrations and offers good selectivity in the presence of other elements commonly found in copper alloys (e.g., zinc, phosphorus, lead).

Accurate tin determination is critical for:

Compliance with alloy specifications.
Quality assurance in applications such as bearings, springs, marine equipment, and electrical components where tin enhances performance.
Avoiding problems such as brittleness caused by excessive tin or reduced conductivity caused by impurities.

These types of standards have been harmonized across Europe and can be adopted nationally.

The standard “EN 15022-3 Part 3: Low tin content - Flame atomic absorption spectrometry method (FAAS)” describes a flame atomic absorption spectrometric (FAAS) method for determining the tin content of copper and copper alloys in raw, processed, and cast products. This method is applicable to products with low tin mass percentages between 0,001% and 0,6%.

This testing method is based on the following principles:

Dissolving a test sample in hydrochloric acid and hydrogen peroxide.
Extraction of tin into the organic phase by solution of trioctylphosphine oxide and methylisobutylketone, followed by aspiration of the organic solution into a nitrous oxide/acetylene flame of an atomic absorption spectrometer.
Measurement of the absorption of the 286,3 nm line emitted by a hollow tin cathode lamp.

This standard applies to the determination of tin in copper and copper alloys in various forms: unprocessed (e.g., ingots), processed (e.g., sheets, bars, tubes), and cast products.

This standard is designed specifically for low tin mass ratios, typically in the range of 0,001% to 0,6% (exact limits may vary slightly depending on calibration and interference, but it is excellent at trace levels where other methods lack accuracy).

It is ideal for alloys with minimal tin content, such as some high-conductivity coppers or brasses where tin is present as an impurity or a small additive.

Flame atomic absorption spectrometry (FAAS) is a widely used technique in analytical laboratories for determining the quantity of elements. FAAS offers good sensitivity, accuracy, and speed for low tin contents, making it a preferable method for routine quality control compared to classical wet chemistry methods.

Precise tin analysis is necessary for the following:

Verification of conformity to alloy specifications.
Ensuring material performance in applications such as electrical connectors (low tin for conductivity), marine equipment, or bearings (controlled tin for wear resistance).
Detection of trace amounts of tin impurities that may affect properties such as ductility or hot workability.
The standard “EN 15022-4 Part 4 Intermediate tin content - Flame atomic absorption spectrometric method (FAAS)” describes a flame atomic absorption spectrometric (FAAS) method for determining the tin content of copper and copper alloys in raw, processed, and cast products. This method is applicable to products with an intermediate tin mass content between 0,2% and 3,0%.

This testing method is based on the following principles:

A test sample is dissolved in hydrochloric acid and hydrogen peroxide, then appropriately diluted, and subsequently aspirated into a nitrous oxide/acetylene flame of an atomic absorption spectrometer.
Absorption of the 286,3 nm line emitted by a tin-hollow cathode lamp.

This standard applies to the determination of tin in copper and copper alloys in all product forms, including raw (e.g., ingots), processed (e.g., bars, sheets, tubes, wires), and cast products.

This standard specifically targets moderate tin mass ratios, typically in the range of 0,2% to 3% (up to higher levels depending on dilution and calibration, suitable for alloys such as tin bronzes where tin is a significant additive).

Tin is essential for alloys such as phosphor bronzes or brass, where it provides improved strength, wear resistance, and corrosion properties in applications such as bearings, gears, valves, and marine components.

Flame atomic absorption spectrometry (FAAS) is a standard laboratory technique for sensitive elemental analysis. The main steps are as follows:

Sample dissolution: The alloy sample is dissolved using a mixture of acids (typically combinations of nitric or hydrochloric acid) to release the tin into the solution while keeping the copper matrix under control.
Preparation for analysis: Dilution and addition of possible matrix modifiers or release agents to minimize interference from copper or other elements.
Atomization and measurement: The solution is aspirated into an air-acetylene or nitrous oxide-acetylene flame (the latter is usually preferred for tin to avoid chemical interference). Tin atoms absorb light from the hollow cathode lamp at a characteristic wavelength (usually 224,6 nm or 286,3 nm).
Quantification: Absorbance is measured and compared to a calibration curve derived from known tin standards using matrix matching to ensure accuracy.
Interference management: Background correction techniques address potential overlaps that may arise from other alloying elements.

For medium tin levels, this FAAS variant offers excellent accuracy and is faster than classical methods, making it ideal for routine testing and material certification in foundries.

Determining the reliable amount of tin allows for the following:

Compliance with composition standards.
Optimal material properties: Too little tin reduces strength, too much can cause brittleness.
Quality in industries such as automotive, aerospace, plumbing, and electrical engineering.

This nationally adopted standard promotes consistency across Europe.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services to businesses in accordance with the "EN 15022 Copper and copper alloys - Determination of tin content" standard.