Project Introduction

Salt spray testing is an environmental test that primarily uses salt spray testing equipment to simulate an artificial salt spray environment for evaluating the corrosion resistance of products or metal materials. It is divided into two main categories: natural environment exposure tests and artificial accelerated salt spray environment simulations. Artificial salt spray environment simulations utilize a test equipment with a certain volume — the salt spray chamber — where, through artificial means, a salt spray environment is created to assess the salt spray corrosion resistance quality of the product. Compared to natural environments, the salt concentration of the chloride in the salt spray environment can be several or even dozens of times higher than that of natural salt spray content, significantly increasing the corrosion rate and drastically shortening the time to obtain results from salt spray tests.

Salt Spray Test Classification

Neutral Salt Spray Test (NSS Test)

It introduces an accelerated corrosion test method in the current application field. The method uses a 5% sodium chloride saltwater solution, adjusting the pH to the neutral range (6-7) as the spray solution. The test temperature is set at 35°C, with a requirement for the salt mist deposition rate to be between 1-2 ml/80 cm².h.

(2) Acetate Fume Test (ASS Test)

Developed on the basis of neutral salt spray tests, this process involves adding a small amount of glacial acetic acid to a 5% sodium chloride solution, reducing the pH to approximately 3, thereby making the solution acidic and transforming the salt spray from neutral to acidic. Its corrosion rate is about three times faster than the NSS test.

(3) Copper Salt Accelerated Acetic Acid雾试验 (CASS Test)

A newly developed rapid salt spray corrosion test in foreign countries, conducted at a temperature of 50°C, involves adding a small amount of copper salt—copper chloride—to the salt solution, which strongly induces corrosion. Its corrosion rate is approximately 8 times faster than the NSS test.

(4) Variable Salt Spray Test

This is a comprehensive salt spray test, which is essentially a combination of the neutral salt spray test and a constant humidity and heat test. It is primarily used for whole machines with cavities, allowing salt spray corrosion to occur not only on the surface but also internally due to the penetration in a humid environment. It involves alternating the product between salt spray and humid heat conditions to assess whether there are any changes in the electrical and mechanical properties of the whole machine product.

Testing Method

Test Project: Salt Mist Test

Reference Standards: IEC60068-2-11 (GB/T2423.17), ISO 4628.3, ASTM B117, JIS-Z2371...

Common Test Parameters:

Salt spray can be divided into three categories:

Neutral Salt Spray Test (NSS Test) - Solution pH adjusted to neutral range (6.5-7.2), test temperature at 35°C

Acetate Mist Test (ASS Test) (Solution: Add some glacial acetic acid, pH value drops to around 3)

Copper Salt Accelerates Acetic Acid Salt雾 Test (CASS Test) - Conducted at 50°C, with a small amount of copper salt - copper chloride added to the salt solution.

Test Time: 16H (Less)

Method Standards

GB/T 2423.17; IEC 60068-2-11; GB/T 10125; ISO 9227; ASTM B 117;

GB.T 2423.18; IEC 60068-2-52; ASTM B 368; MIL-STD-202; EIA-364-26