ASTM F483 Standard Test Method for Total Immersion Corrosion Testing for Aircraft Maintenance Chemicals

The standard “ASTM F483 Standard test method for full immersion corrosion testing for aircraft maintenance chemicals” published by the American Society for Testing and Materials (ASTM) describes a test method for determining the corrosivity of aircraft maintenance chemicals on aircraft metals as a function of time under full immersion conditions by a combination of weight change measurements and visual qualitative change determination methods.

Many aircraft maintenance chemicals are used on components and structures that could be adversely affected by excessive dimensional change. This practice allows these chemicals to be screened to ensure compliance with specified weight change criteria.

The main equipment used in these tests includes:

• A suitably sized, wide-mouth, sealable glass jar or stoppered flask: The glass jar or flask should be selected so that the specimens remain fully immersed in a vertical position during the test, and the immersed metal area to solution volume ratio should be 1:8. Some aircraft maintenance chemicals can have high vapor pressures when heated or may generate gas during the test. Appropriate precautions should be taken to prevent the containers from bursting, or the container should be selected to withstand the resulting pressure.
• Sample support device: A glass or fluorocarbon plastic support system designed to keep the sample completely immersed while providing free contact with the solution and to physically isolate the samples from each other.
• For materials containing low-boiling solvents, a method that prevents evaporation losses must be used.
• Constant temperature device: Any conveniently regulated heating device (mantle, hot plate or bath) may be used to maintain the solution at the desired temperature.
• Thermometer with a temperature range of 95 to 155 degrees and conforming to the requirements for S67C or S67F thermometers per ASTM E2251 standard.
• Low temperature explosion-proof furnace that can maintain temperatures between 38 degrees plus/minus 3 degrees and 120 degrees plus/minus 5 degrees.

Reagents and materials used in the tests are:

• Acetone: Must comply with ASTM D329 standard.
• Methyl n-propyl ketone.
• Mineral spirits must comply with Type II: ASTM D235.

Test samples are taken from the same sheet metal, of a specific alloy, in new or near-new condition, and measure 50,8 mm x 25,4 mm x 1,6 mm with a 3,2 mm diameter mounting hole conveniently located at one end of the sample. Three replicate samples are tested at each maintenance chemical solution concentration. The total sample area is taken as 28,2 cm2. Each panel is identified by the numbers 1, 2, 3, or 4.

For pre-cleaning, test samples are immersed in a beaker filled with Type II mineral spirits conforming to ASTM D235 at room temperature. Using a clean forceps to hold the test sample and cotton swab, the surface of each sample is thoroughly wiped. Excess solvent is shaken off. Test samples are individually transferred to a beaker filled with methyl n-propyl ketone and immersed several times. The excess methyl n-propyl ketone is shaken off and dried in a vacuum desiccator or a low-temperature oven at 120°C (plus/minus 5°C) for 15 minutes. (If oven-dried, place in a desiccator and cool to ambient temperature.)

The ratio of the immersed metal area to the solution volume should be 8 mL per cm². Fresh solution is used for each set of replicates. Unless otherwise specified, samples are tested in solutions of the maintenance chemical, concentrated as received, and at the recommended use dilution using water conforming to ASTM D1193 Type IV. If the maintenance chemical does not dissolve to the specified extent, this is recorded and the test is continued. If water is not used as a diluent, the type of diluent used in the test and its specification are recorded. Unless otherwise specified, the test temperature should be 38°C plus/minus 3°C.

The following steps are performed during testing:

• Three out of four samples of the same alloy are weighed to the nearest 0,1 mg.
• Three weighed samples of each alloy are immersed in the test solution at the specified temperature. Only samples from the same alloy are placed in the container. The required temperature is maintained for the specified exposure time. A fourth sample of each alloy is retained for comparison.
• After 24 hours, test samples are removed and the process continues as follows:
  • Rinse thoroughly under hot tap water between 49°C and 60°C. Then rinse with room temperature water conforming to ASTM D1193 Type IV.
  • From the wash bottle, it is rinsed with acetone flow in accordance with the ASTM D329 standard and dried in the oven at 120 degrees until it cools to ambient temperature, weighed and recorded.
  • The following visible changes are then examined and recorded when compared with the fourth virgin sample of each alloy in a spreadsheet as shown in Annex X1, in the 24-hour column.
    • Discoloration and dulling
    • Abrasion
    • Presence of deposits and relative amounts
    • Pitting
    • Presence of selective or localized attack.
• The panels are immersed in the same test solution for another 144 hours, after which the previous steps are repeated.
• Samples are reweighed to the nearest 0,1 mg, the weight loss or gain calculated and recorded in the 168-hour column.

As shown in the appendix to the standard, data for each test performed are reported in a form (Appendix X1).

The ASTM E483 standard is important because it provides a standardized and reliable method for evaluating how aircraft maintenance chemicals affect metal materials used in aircraft construction. The key reasons for this standard's importance include:

• Ensures chemical compatibility with aircraft metals: Aircraft maintenance involves the use of cleaners, lubricants, de-icers, solvents, and similar materials. These chemicals can be corrosive to materials such as aluminum, titanium, or steel. ASTM E483 helps determine whether a chemical is safe for long-term use on these metals.
• Supports aircraft safety and airworthiness: This standard demonstrates that corrosion can lead to structural failure or degraded performance. Testing chemicals under total immersion simulates worst-case exposure scenarios. By detecting corrosion reactions early, this testing prevents material degradation and potential in-service failure.
• Provides a quantitative and repeatable assessment method: The described test method measures the weight loss, surface condition, and corrosion type of the metal sample. These results are objective and comparable, enabling manufacturers to make data-driven decisions.
• Standardized testing means industry consistency: This standard is used across the aerospace industry, including original equipment manufacturers and chemical suppliers. It ensures consistent quality control, product approval, and regulatory compliance.
• It is part of a broader corrosion prevention strategy. ASTM F483 is often used in conjunction with other standards (e.g., ASTM F1110 for sandwich corrosion). It aids in the development or selection of non-corrosive, aircraft-approved maintenance products.

As a result, the ASTM E483 standard protects aircraft integrity by ensuring that chemicals used during maintenance do not corrode critical materials, thereby promoting safety, compliance, and reliability in the aviation industry.

Our organization, which has been supporting businesses across all sectors for years through a wide range of testing, measurement, analysis, and evaluation activities, has a strong team of employees who closely follow global developments in science and technology and are constantly improving themselves. In this context, we also provide testing services in accordance with the "ASTM F483 Standard Test Method for Full Immersion Corrosion Testing for Aircraft Maintenance Chemicals."