Test Background
Scratches on metal that penetrate a paint or varnish film can produce various types of corrosion, such as film bubbles, undercoat metal corrosion, and filiform corrosion. Filamentous corrosion often occurs under certain temperature and humidity conditions, induced by an appropriate amount of acid, alkali or salt, where the coating film is weak or damaged. These conditions exist for filiform corrosion to occur at seaside or in industrial environments.
Substrate corrosion under the paint film usually begins at scratches. The typical form of filamentous corrosion is clearly visible filaments.
The filiform corrosion resistance test of aluminum and aluminum alloy surface coatings can evaluate the filamentous corrosion resistance and degree of filamentous corrosion of aluminum and aluminum alloy surface paints and varnish coatings. It is only applicable to aluminum and aluminum alloy surface paints and varnish coatings to evaluate the filamentous corrosion resistance of the tested coating/substrate.
Zhongke Testing Reliability Experiment Center has the capability of reliability testing of various paints and varnishes, and provides professional filiform corrosion resistance testing services for aluminum and aluminum alloy surface coatings.
Scope of tests
Color paint is divided into primer and topcoat: primer is divided into primer, putty, mid-coat, sealer, anti-rust paint, etc.; topcoat is divided into enamel paint, special topcoat, etc.
The paint and film of varnish are transparent and are divided into ester varnish, shellac varnish, phenolic varnish, alkyd varnish, acrylic varnish, polyester varnish, high-performance varnish, fluorocarbon varnish, etc.
Test method
The specimen is scratched in a prescribed manner. A small amount of hydrochloric acid is introduced into the scratch by exposing the specimen to saturated hydrochloric acid vapor. The sample is then placed in a test chamber at (40±2)℃ and relative humidity (82±5)% for testing.
The evaluation of test results shall be carried out in accordance with the provisions of this standard or shall be agreed upon by both parties.
Test standard:
GB/T 26323-2010 Paints and varnishes - Filiform corrosion resistance test of aluminum and aluminum alloy surface coatings
ISO 4623-2: 2016 Paints and varnishes - Determination of resistance to filiform corrosion - Part 2: Aluminum substrate
EN ISO 4623-2: 2016 Paints and varnishes Determination of resistance to filiform corrosion Part 2: Aluminum substrate
DIN EN ISO 4623-2: 2016 Paints and varnishes Determination of resistance to filiform corrosion Part 2: Aluminum substrate
NF EN ISO 4623-2: 2016 Paints and varnishes Determination of resistance to filiform corrosion Part 2: Aluminum undercoat
BS EN ISO 4623-2: 2016 Paints and varnishes Determination of resistance to filiform corrosion Part 2: Aluminum substrates
