Sandwich Corrosion Test of Aircraft Maintenance Materials ASTM F1110

Sandwich corrosion test is determined by the standard method ASTM F1110. This Sandwich Corrosion test method defines the procedure for evaluating the corrosivity of aircraft maintenance chemicals, when present between faying surfaces of aluminum alloys, commonly used for aircraft structures.

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Introduction

The ASTM F1110 provides a reproducible basis for determining the impact of these materials on the corrosion of aluminum alloys most widely used in aerospace applications. Sealants, lubricants, and cleaners are crucial for preserving the integrity and safety of aircraft systems. However, such materials frequently interact with structural members in ways that encourage corrosion, potentially adversely affecting structural integrity. This test is vital for the aerospace industry, as it helps manufacturers, maintenance providers, and regulators be assured that the maintenance materials cannot damage the structural components of an aircraft. With its simulation in realistic environments, the ASTM F1110 test becomes crucial in determining the compatibility of these materials with aircraft parts.

Scope

ASTM F1110’s standard Sandwich Corrosion test technique assesses whether aircraft structural aluminum alloys are susceptible to corrosion or damage when the test material is applied during routine maintenance operations. The technique qualifies and approves compounds used in airplane maintenance operations. The relative corrosion severity rating system is proposed to reduce the need for complex weight loss measurements and provide a numerical classification of test results.

Test Procedure

In ASTM F1110, aluminum coupons with clad or anodized non-clad surfaces are sandwiched with filter paper soaked with the test material. For seven days, the sandwiched coupons are alternately exposed to warm ambient air and warm, humid air. The coupons are then examined to see if there has been more severe corrosion than that induced by reagent water on the areas exposed to the test materials. This sandwich corrosion test method addresses dry granular or liquid material issues.

Sample Size

The following are the technical specifications of ASTM F1110:

Sample size	According to ASTM F110, the recommended coupon size is 50 by 100 by 1.0 to 1.5 mm, and the recommended filter paper size is 11 or 13 cm.
Sample preparation	In ASTM F1110, sample preparation involves assembling a sandwich structure using aluminum alloy panels, typically cleaned to remove contaminants. The maintenance material under evaluation is applied between the panels. The assembly is clamped or secured to ensure proper contact and then conditioned for exposure to the specified test environment, simulating realistic operational conditions.

Result

The results obtained from the ASTM F1110 test are essential in determining whether a maintenance material is suitable for use in the aerospace environment. The material is compared against control samples or set standards to decide whether or not it has met the set standards. Materials that induce minimal or no corrosion are compatible, while those causing significant corrosion are flagged for reformulation or restricted use in aerospace applications.

Extent of Corrosion
Corrosion Rating
Visual and Microscopic Analysis
Impact on Material Properties

Conclusion

ASTM F1110 plays an essential role in ensuring the safety and longevity of aircraft structures by assessing the corrosion potential of maintenance materials. Critical to aeronautical applications, where aerospace must prevent corrosion, this test standard allows manufacturers and maintenance teams to select materials that meet strict requirements for aviation safety. ASTM F1110 is the cornerstone for aircraft maintenance materials testing between performance assurance and regulatory compliance. The standardized approach helps ensure that aerospace maintenance practices promote the highest levels of safety and reliability. Consequently, trust within the aviation industry is maintained.

FAQs

What is sandwich corrosion?

The Sandwich Corrosion Test is a standard method for evaluating the corrosion resistance of aircraft maintenance materials, particularly those used to repair and overhaul aircraft structures.

What are the four main types of corrosion?

Metals may be exposed to various types of local corrosion in specific environments, including pitting, crevice, intergranular, stress, and galvanic corrosion. Even a single alloy can experience multiple types of corrosion based on its exposure to different conditions at various locations within a system.

What is aircraft corrosion in the bilge area?

These areas naturally accumulate waste hydraulic fluids, water, dirt, and debris remnants. Often, residual oil contains small amounts of water that settle at the bottom, creating an unseen chemical reaction.