Salt spray test is an environmental test that mainly uses artificially simulated salt spray environmental conditions created by salt spray test equipment to evaluate the corrosion resistance of products or metal materials. It is divided into two categories, one is the natural environment exposure test, and the other is the artificial accelerated simulated salt spray environment test. The artificial simulated salt spray environment test is to use a kind of test equipment with a certain volume of space-the salt spray test box, using a manual method in its volume space to create a salt spray environment to evaluate the product's salt spray corrosion resistance . Compared with the natural environment, the salt concentration of the chloride in the salt spray environment can be several times or tens of times of the general natural environment salt spray content, which greatly improves the corrosion rate. The time is also greatly reduced. For example, if a product sample is tested in a naturally exposed environment, it may take one year to corrode. However, if the test is performed under artificially simulated salt spray conditions, as long as 24 hours, similar results can be obtained. The following are the three major salt spray test methods provided by Shanghai Linpin Instrument Co., Ltd.
1. The neutral salt spray test (NSS test) is the earliest and most widely used accelerated corrosion test method. It uses 5% sodium chloride salt water solution, and the PH value of the solution is adjusted to a neutral range (6-7) as a spray solution. The test temperature is 35 ℃, and the sedimentation rate of salt spray is required to be between 1 ～ 2ml / 80cm? .H.
2. Acetate salt spray test (ASS test) is to add some glacial acetic acid to the 5% sodium chloride solution to reduce the PH value of the solution to about 3, the solution becomes acidic, and the final salt spray is also formed by neutral salt The mist becomes acidic. Its corrosion rate is about 3 times faster than the NSS test.
3. The Copper Accelerated Acetate Salt Spray Test (CASS Test) is a fast salt spray corrosion test recently developed abroad. The test temperature is 50 ° C. A small amount of copper salt-copper chloride is added to the salt solution to strongly induce corrosion. Its corrosion rate is about 8 times that of the NSS test.
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