The neutral salt spray test (NSS:Neutral Salt Spray test) is in a specific test box. The spray is carried out by the spray device containing (5 and 0.5)% NaCl and pH value of 6.5 ~ 7.2. The salt mist will be deposited on the test specimen and the corrosion state of the surface is observed for a certain time. The temperature of the test chamber should be (35 65 Neutral salt spray is a kind of corrosive medium with 5% NaCl solution. The corrosive test of the sample in marine environment and climate is carried out. Neutral salt spray is widely used in metal and its alloys, metal coating, organic coating, anodic oxide film and conversion film. Among the three types of salt spray corrosion (NSS, AASS, CASS), the corrosion is the weakest. Test method of neutral salt fog and standard GB/T 10125 artificial atmosphere corrosion test salt fog test ISO 9227 Corrosion tests in artificial atmospheres Salt spray tests JIS Z2371 salt mist test method to meet different test purposes A variety of evaluation criteria can be used, such as weight change, microscopic observation, mechanical properties, etc. Usually, the evaluation criteria of test results should be proposed by the coated layer or product standard. For the general test, the conventional records only need to consider the following aspects: the appearance after the A. test; the appearance of the B. after the corrosion products; the C. corrosion defects, such as the distribution and quantity of pitting, cracks, bubbles and so on. Note: the above three aspects can be evaluated by the method of GB 6461 - 86 "the rating of the metal cover layer for the plating specimen after the corrosion test of the cathode cover layer." D. begins to have a time of corrosion