What is the salt spray test? Salt spray test standard and method

Date：2021-07-27 16:45:00Views：1615

Salt spray test is an environmental test that mainly uses the artificial simulated salt spray environmental conditions created by salt spray test equipment to evaluate the corrosion resistance of products or metal materials. GB / t2423 product salt spray test center -- national salt spray test centerSalt spray test GB / t2423 17-2008 / iec60068-2-11:1981 environmental test of electrical and electronic products Part 2: Test Method: Test Ka: salt spray.

This test is applicable to comparing the salt spray corrosion resistance of samples with similar structure.

This test is also applicable to evaluate the quality and uniformity of protective coatings.

Salt spray test can be divided into two categories, one is natural environment exposure test, the other is artificial accelerated simulated salt spray environment test. Artificial simulated salt spray environment test is to use a test equipment with a certain volume space - salt spray test chamber to create a salt spray environment by artificial method in its volume space to evaluate the salt spray corrosion resistance and quality of products.

Salt spray test mainly includes the following tests:

Salt spray test; Acid salt spray test; Copper ion accelerated salt spray experiment; Cyclic salt spray test; Water mist experiment; 100% relative humidity resistance test;

Artificial simulated salt spray test includes:;Neutral salt spray test, acetate spray test, copper salt accelerated acetate spray test, alternating salt spray test.

(1)Neutral salt spray test (NSS test)It is the earliest and most widely used accelerated corrosion test method. It uses 5% NaCl solution, and the pH of the solution is in neutral range (6~7) as a spray solution. The test temperature is 35 ℃, and the sedimentation rate of salt spray is required to be 1 ~ 2ml / 80cm2 H.

(2)Acetate spray test (ASS test)It is developed on the basis of neutral salt spray test. It is to add some glacial acetic acid to 5% sodium chloride solution to reduce the pH value of the solution to about 3, turn the solution into acid, and finally form a salt mist from neutral salt mist to acid. Its corrosion rate is about 3 times faster than that of NSS test.

(3)Copper salt accelerated acetate spray test (CASS test)）It is a rapid salt spray corrosion test developed recently abroad. The test temperature is 50 ℃, and 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 NSS test.

(4)Alternating salt spray testIt is a comprehensive salt spray test, which is actually a neutral salt spray test plus constant damp heat test. It is mainly used for cavity type complete machine products. Through the penetration of humid environment, salt spray corrosion occurs not only on the surface of the product, but also inside the product. It is to alternately convert the product under salt fog and humid and hot environmental conditions, and finally check whether the electrical and mechanical properties of the whole product have changed.

The following limitations should be considered when using:

1. This test is not suitable for general salt spray corrosion test;

2. This test is also not applicable to the evaluation of a single test sample used in saline atmosphere.

For equipment and parts, the test provides test conditions more in line with the actual situation and the evaluation method of a single test sample. However, if in some cases, in order to ensure quality, relevant specifications require individual samples to adopt this test method, the samples shall be tested as an integral part of the whole assembly or equipment together with the actual protective performance equipment.

The concentration of the salt solution used for the test is 5%, the test temperature is 35 ℃, and the pH value of the salt solution is between 6.5-7.2.

During the test, each test sample shall not contact or contact with other metal parts, so the sample shall be placed to eliminate the influence between parts.

Salt spray conditions shall be maintained in all exposed areas. Use vessels with an area of 80cm2 to continuously collect atomized deposition solution at any point in the exposed area for at least 16 hours, and the average collection amount per hour shall be between 1ml-2ml. At least two collection vessels shall be used. The position of the vessel shall not be covered by the sample to avoid collecting the condensed solution on the sample. The solution in the vessel can be used to test the pH value and concentration.

The time of salt spray test is generally 16h, 24, 48, 96148336672 hours.

The salt spray test standard specifies the salt spray test conditions, such as temperature, humidity, sodium chloride solution concentration and pH value. In addition, it also puts forward technical requirements for the performance of the salt spray test chamber. Which salt spray test standard shall be adopted for the same product shall be selected according to the characteristics of salt spray test, metal corrosion rate and sensitivity to salt spray.

Environmental tests for electric and electronic products Part 2: Test methods Test Ka: salt spray GB / T 2423.17-2008 / IEC 60068-2-11:1981

Basic technical conditions for automotive electrical equipment QC / T 413-2002

Military equipment laboratory environmental test methods Part 11: salt spray test GJB 150.11a-2009

General specification for military communication equipment GJB 367a － 2001

General specification for military computer GJB 322a-1998

General specification for military electronic test equipment gjb3947a-2009

Test methods and procedures for microelectronic devices GJB 548b-2005

Test methods for electronic and electrical components GJB 360b-2009

Marine electronic equipment environmental test salt spray test GJB 4.11-1983

Corrosion test in artificial atmosphere salt spray test GB / T 10125-2012 / ISO 9227:2006

Environmental testing Part 2: Test methods Test Kb: salt spray, alternating (sodium chloride solution) GB / T 2423.18-2012 / IEC 60068-2-52:1996

Rail transit rolling stock electronic devices GB / T 25119-2010 / IEC 60571:2006