Huanren Lab

 Project Introduction

Salt spray testing is an environmental test that mainly uses artificially simulated salt spray environmental conditions created by salt spray testing equipment to assess the corrosion resistance of products or metal materials. It is divided into two categories: one is natural environmental exposure test and the other is artificially accelerated simulated salt spray environmental test. Manually simulated salt spray environment test is a test equipment with a certain volume space - a salt spray test chamber, which uses artificial methods in its volume space to create a salt spray environment to assess the product's salt spray corrosion resistance performance quality. Compared with the natural environment, the salt concentration of chloride in its salt spray environment can be several times or dozens of times that of the salt spray content of the general natural environment, which greatly improves the corrosion rate. The salt spray test on the product will greatly shorten the time for obtaining the results.

Salt spray test

(1) Neutral salt spray test (NSS test)

It is the earliest and most widely used accelerated corrosion test method. It uses a 5% sodium chloride saline solution, and the solution pH value is adjusted to the neutral range (6-7) as a solution for spraying. The test temperatures are all 35℃, and the sedimentation rate of salt spray is required to be between 1 and 2ml/80cm2.h.

  (2) Acetate spray test (ASS test)

It was developed based on the neutral salt spray test. It adds some glacial acetic acid to the 5% sodium chloride solution, which reduces the pH value of the solution to about 3, and the solution becomes acidic, and the final salt spray also turns from neutral salt spray to acidic. Its corrosion rate is about 3 times faster than that of NSS tests.

  (3) Copper salt accelerated acetate spray test (CASS test)

It is a fast salt spray corrosion test recently developed abroad. The test temperature is 50℃. A small amount of copper salt-copper chloride is added to the salt solution, which strongly induces corrosion. Its corrosion rate is about 8 times that of the NSS test.

  (4) Alternating salt spray test

It is a comprehensive salt spray test, which is actually a neutral salt spray test plus a constant humidity and heat test. It is mainly used for cavity-type whole machine products. Through the penetration of the damp environment, salt spray corrosion not only occurs on the surface of the product, but also inside the product. It alternately converts the product under two environmental conditions: salt spray and humidity, and finally evaluates whether there are any changes in the electrical and mechanical properties of the entire machine product.

Test Method

Test items: 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 experiment) (solution: adjust the pH value to the neutral range (6.5~7.2), and the test temperature is 35℃)

Acetate Smoke Test (ASS Experiment) (Solution: Add some glacial acetic acid, the pH value is reduced to about 3)

Copper salt accelerated acetate spray test (CASS experiment) (test temperature is 50℃, add a small amount of copper salt-copper chloride to the salt solution)

Test time: 16H (minimum)

Reference 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