Say what you will about the intricacies of environmental testing, but the names used to identify individual test chamber models couldn’t be simpler. Temperature only chambers enable users to control the temperature within the chamber. Temperature and humidity test chambers manipulate both temperature and humidity conditions. Thermal shock chambers draw their name from the act of quickly exposing (and subsequently removing) devices under test (DUT) to extreme, opposite temperatures, thus ‘shocking’ them.
You can guess, then, just what a salt spray test chamber does: It exposes DUTs to corrosive conditions by filling the chamber with a salt spray (or fine mist).
Corrosion is inevitable and stems from a number of environmental factors including moisture, temperature, and acidity in addition to the presence of salt. Although it can’t be entirely prevented, it can be slowed down. Companies can determine how corrosion-resistant a material, product, component, or coating is through salt spray testing. In doing so, they set expectations for use or return to research and development to design a better solution.
Salt spray testing is particularly important to companies in the marine and automotive industries or whose products will be used primarily outdoors, or must perform in a mechanical load-bearing role. It’s also crucial for electronics companies: Cell phones and tablets need to perform as well in coastal climates as in dry ones.
Here’s what you need to know about salt spray testing and salt spray test chambers.
Salt Spray Tests & Cyclic Corrosion Testing
Although it’s called a salt spray test and salt spray test chamber, that name is a little misleading. The spray usually comes in the form of a fog or super fine mist that creates an environment that accelerates corrosion. This condition is also isolated by controlling the ambient temperature at 95°F (35°C) and ph level of the water.
Salt spray tests are used to determine the corrosive resistance of materials. These often include the following:
- Phosphated surfaces with subsequent paint, primer, lacquer, or rust preventive
- Zinc and zinc-alloy plating
- Electroplated chromium, nickel, copper, and tin
- Coatings not applied electrolytically, such as zinc flake coatings
- Organic coatings
- Paint coatings
For a more comprehensive understanding of how a product or component will resist corrosion in real-world environments, you’ll need to conduct what’s known as a cyclic corrosion test. Similar to HALT testing, the goal of the test is to determine when a product fails in a controlled environment to set expectations for consumers or assess the need for further testing. Users cycle DUTs through higher temperatures, then lower temperatures to simulate accelerated time passing.
Think of this scenario: You’re an auto parts company designing new brake lines intended to stand up better to harsh northern winters. You’d put the coating and material through salt spray testing to evaluate its resistance to corrosion. To identify just how long the brake lines remain effective—factoring in corrosive environmental conditions, extreme temperatures, humidity, dust, vibrations, or more-—you’d develop a cyclic corrosion test. That way you can deliver reasonable expectations and measure your product against others in the market.
The Importance of Salt Spray Testing
It doesn’t take much evidence to understand how corrosion negatively impacts our lives, and it goes beyond the unseemly sight of rust.
Drivers in northern climates know the importance of corrosion-resistant materials well. The buildup of salt on winter roads wreaks havoc on the undercarriage of cars, especially those best described as ‘beaters’ or ‘clunkers.’ The corrosion poses a threat to the safety of the driver as well as to all others on the road.
Just as automobile companies focus a portion of their research efforts on developing corrosive-resistant parts, municipalities focus on the roads themselves. The combination of salt and water erodes the asphalt and concrete, sometimes below the surface. Potholes are created in its wake. Researchers are addressing this problem by developing water and salt-resistant pavement solutions.
Then there’s a very real public health concern. A 2019 report from the National Association of Corrosion Engineers estimated the direct cost of corrosion in the U.S. drinking water and sewer system at $80 billion. If left unaddressed, contaminated water poses a threat to citizens across the country.
These are just some of the challenges researchers address when salt spray testing. And as they seek to innovate, so too do the manufacturers of salt spray chambers.
Associated Environmental Systems, for example, has developed the unique MX Series. It features two sensors, one that holds and conditions water to an accurate 45.5°C and another that maintains the ambient temperature at 35°C.
The MX Series, with plexiglass on all sides, is also the only chamber on the market that offers users a 360-degree view of the test workspace. You can easily observe the DUT while simultaneously analyzing the data when you fit the chamber with AESONE CONNECT instrumentation.
This is a comprehensive salt spray test chamber that gives you as much control as possible. When it comes to limiting corrosion and guaranteeing the effectiveness of your products, you can’t leave anything to chance.
