What is Salt Fog and Salt Spray Testing?
Salt Fog and Salt Spray Testing is a kind of environmental test, mainly used to evaluate the corrosion resistance performance of products or metal materials. There are two ways of testing: natural environment exposure test and artificial simulated salt spray environment test. Natural environment exposure test is to expose the product to the external environment, to observe its corrosion resistance performance under natural conditions. The artificial salt spray environment test uses a specific device (Salt Spray Test Chamber) to simulate a high-concentration salt spray environment to accelerate the evaluation of corrosion resistance performance. It can improve the rate of salt spray corrosion and shorten the testing time.
Purpose of Salt Spray Test Chamber:
Salt Spray Test Chamber can effectively detect the anti-salt spray corrosion ability of products or metal materials, and the salt spray testing standard makes clear requirements for the various conditions of salt spray testing, with the technical requirements of Salt Spray Test Chamber performance, to ensure the accuracy and accuracy of salt spray test equipment, to measure the anti-salt spray corrosion quality of products or auxiliary materials correctly. Therefore, in order to ensure the accuracy of test results, it is necessary to use strict salt spray standards to ensure the effectiveness and continuity of testing.
Importance of Salt Spray Test Chamber
Salt Spray Test Chamber is very important, it can help products effectively resist corrosion in environments containing high concentrations of chloride ions. It is a system that simulates the atmosphere environment, which can be applied to salt spray corrosion experiments of products. The Salt Spray Test Chamber can perform 4 different salt spray corrosion tests according to different environments, which are neutral salt spray test, acetic acid salt spray test, copper salt accelerated acetic acid salt spray test and alternating salt spray test. These tests can be tested at a greater concentration than the natural environment to test the corrosion of the sample, and results can be obtained in a shorter period of time. Therefore, the Salt Spray Test Chamber is an important device to prove that the product can still effectively resist corrosion under environmental pollution conditions.
Industrial Applications of Salt Spray Test Chamber
Salt spray test is mainly used to detect the acid and alkali resistance and stability of various materials, devices and equipments. This test first uses sodium chloride solution and adjusts the concentration of the solution, and then immerses the sample for testing. Put the solution in a certain room temperature (20-35℃) and humidity (50-90%), and measure the humidity and temperature to detect whether the sample is corroded. Finally, the corrosion
Salt spray test is a test method for testing the corrosion resistance of materials in extreme harsh environment. The following will analyze the several main factors that affect the result of salt spray test:
A. Test temperature and humidity
When the relative humidity reaches more than 70%, the salt solution will hydrolyze to form conductive electrolyte solution, and the corrosion rate will be increased by 2-3 times for every 10℃ increase of the salt solution temperature, but the too high temperature will make the test result deviate from the actual situation greatly. Therefore, most scholars think that the test temperature should be 35℃.
B. Salt solution concentration
Different metals have different sensitivity to the concentration of salt solution, for example, the corrosion rate of steel, nickel, brass etc. will increase with the decrease of the concentration below 5%, when the concentration reaches 5%, the oxygen content in water solution will reach saturation, and the corrosion rate will slow down with the increase of concentration, while zinc, cadmium, copper etc., the corrosion rate will always increase with the increase of concentration.
C. Sample placement angle
When the sample is placed at 45° angle with the horizontal line, the weight loss due to corrosion is 250g per square meter, but when the sample is placed at 30° angle with the vertical line, it is only 140g per square meter. Detailed requirements for the placement of the sample plate are specified in the national standard GB/T2423.17-93.
D. pH value of salt solution
The lower the pH value of the salt solution is, the higher the concentration of hydrogen ions in the solution is, and the stronger the corrosion is. Compared with neutral salt mist with the pH higher than 6.5, the corrosion rate of the acetic acid salt mist with the pH less than 3.0 is 1.5-2.0 times higher. Therefore, many standards will require a stable pH value during the test to improve the reproducibility of the test results.
E. Duration of the test
The duration of the test will also affect the result, many standards will specify the minimum time of salt spray test, for example, the IEC60355-1971 standard requires that the duration of salt spray test should be at least 2 weeks.
These are the main factors that affect the result of salt spray test, and more accurate test results can be obtained by reasonably controlling the parameters.
Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.
Our main products are Goniophotometer, Integrating Sphere, Spectroradiometer, Surge Generator, ESD Simulator Guns, EMI Receiver, EMC Test Equipment, Electrical Safety Tester, Environmental Chamber, Temperature Chamber, Climate Chamber, Thermal Chamber, Salt Spray Test, Dust Test Chamber, Waterproof Test, RoHS Test (EDXRF), Glow Wire Test and Needle Flame Test.
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