Surfaces & Coatings-ANALYTICS IN THE AREA
Climate and Climate Change Testing
Components can be coated with either metallic or organic materials, such as paints. Often, a material mix is used, for example, where a plastic substrate is refined with a metallic coating or a metallic substrate with an organic paint layer. Different materials exhibit varying behaviors when subjected to cold, heat, or humidity. To prevent optical or technical failures during the later use of the components and parts, we pre-test their behavior under various temperature and humidity conditions.
In climate testing, a defined temperature-humidity profile is performed to the test parts, which they should ideally endure without damage. In some cases, special media, such as harmful gases or corrosive pastes, are added to simulate real-life conditions as authentically as possible. Classic tests include:
Kesternich Test
Testing in Condensation Climates
Climate Change Testing
Corrodkote and Russian Mud
The Kesternich Test uses sulfur dioxide. Sulfur dioxide is produced in combustion engines and is therefore highly relevant for all parts that are "on the move" in road traffic or in industrial halls with operational traffic and corresponding emissions. Due to emissions in road traffic, sulfur dioxide is also partly responsible for acid rain, which means that outdoor components, such as street lamps, railings, or facade parts, are also exposed to it. These are the application cases for the Kesternich Test, which simulates usage-related exposure.
Sulfur dioxide also has the property of uncover heat treatment defects in brass. This is relevant for the sanitary industry, which tests its brass fittings using the Kesternich Test.
Sanitary parts with brass substrates
Engine compartment parts
Wheels, spokes, power unit elements
Facade components
The condensation water climate tests are conducted at a temperature of 40°C and an uncontrolled humidity level between 95% and 100%. The humidity is uncontrolled because it is generated purely through water evaporation. Therefore, during condensation water tests, the test samples are also subjected to dew formation. Testing is done either in a constant climate, where temperature and humidity remain consistent throughout the test period, or in a changing climate, where the chamber is periodically turned off, reducing humidity.
These tests are very informative for organic coatings. Due to the moisture and warm temperature, paints can swell, blister, crack, or chalk.
A special application case for the condensation water constant climate test are hardened steel parts. If there are hardness defects, red rust can form within 100 hours in the test due to carbide precipitations at the grain boundaries.
KTL coatings
Painted parts
Hardened steel parts
In climate change testing, a predefined temperature-humidity profile is automatically performed. Climate change testing is a true all-rounder. It assesses general aging behavior as well as adhesion to the substrate and between single layers.
Every component experiences various climate changes during its later use: indoor and outdoor, summer and winter, extremes such as a car wash. The coating must endure all this without losing its function.
Different materials expand differently. This must be considered in material mixes. For example, if a plastic substrate is metal-coated, the substrate and coating expand differently in heat and contract differently in cold. Under this stress, the coating must neither blister nor crack.
Climate change testing
Temperature shock testing
Heat storage
Cold storage
Special applications require special tests. Even in snowy regions, cars are driven, and to keep roads clear and passable, salt is spread. The residues of snow, salt, and other road dirt accumulate on the vehicle, and in heavy snow, also around the chrome trim or emblems. The acidic, chloride-containing mud is the ultimate enemy for the chrome layer – the chrome is properly eaten away. After a winter, the once beautiful trim elements may no longer look attractive. To prevent this, a synthetic deicing solution is tested beforehand – and because this problem largely occurred in Russia, the associated test is called the Russian Mud Test.
The Corrodkote Test deals with dirt that can deposit on surfaces and either influence them or cause corrosive damage. A dirt-imitating paste is applied, and the test samples are exposed to a condensation climate.
Both tests come in different variations, depending on the part’s intended application in later life.
For enquiries about these analyses, please contact our laboratory team at anfrage@industrial-lab.de or get in touch with your contact person:
BSc Chemical Engineer
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Electroplating technician
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Head of Laboratory
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In a corrosion test, the test specimens are specifically exposed to aggressive conditions that either simulate use in the component's life or are intended to specifically attack the materials. This simulates the worst case scenario for the component and checks whether the material is attacked and how severe the attack is.
Corrosion images provide important insights into the behavior of the materials and their suitability for subsequent installation. This means that any weak points can be detected before the workpiece is used and rectified after the test. This increases product safety.
The test method depends on the material of the component to be tested. Metallic components react very sensitively to chlorides and sulphur compounds. Tests are often carried out with salt spray. In most cases, a sodium chloride solution is finely atomized. The chloride-containing mist washes around the components, settles as fine droplets on the surface and attacks the metal structure. The tests are also selected according to where the component will later be used. Components that are used in a maritime climate or near the coast are specifically exposed to the salty atmosphere. Salt spray tests are also common here. Components that are used in road traffic are also tested for exhaust gas pollution caused by sulphur and nitrogen oxides. This also applies to façade components or materials in the vicinity of agricultural land that are exposed to increased levels of acid rain. There is a suitable corrosion test for every material and every material composite, depending on the area of application.
As the name suggests, climate tests simulate climatic influences. This is particularly interesting and relevant for material combinations, such as a metal-coated plastic part. Plastic and metal differ in their expansion and contraction behavior when the temperature changes. If the “chemistry” between the two materials is not right, cracks (during expansion) or bubbles or folds (during contraction) occur. However, climate tests consist not only of temperature components but also of a moisture phase. The combination of temperature and humidity is particularly challenging for organic materials, such as painted surfaces or plastics.
By exposing these materials to a defined climate, the tendency to embrittlement or, in the case of paint coatings, to blistering or chalking can be tested, for example. However, climate tests are also good indicators of heat treatment defects in steels, which show up within 100 hours as red rust on what is actually stainless steel.
