Salt Mist

Salt mist/spray test is a standardized test method to check corrosion resistance of coatings and entire products. Corrosion not only affects metals, but also high-alloyed, tempered materials, plastics and painted surfaces. The test duration depends on the environmental conditions of the product in real life. High humidity, salty air, seawater and gritting salt influence corrosiveness of the product.

Salt mist/spray testing is popular because it is quick and well-standardized. To accelerate the corrosion, it is possible to introduce scratches in a coating. The length of the dendrites formed during the corrosion test is a coating quality measure. Salt mist testing is often used for quality control of materials and less for predicting the lifetime of a product in the real world.

For the execution of a salt mist/spray test, it is important to define which standard to use, how long samples should be exposed, what the inspection criteria are, inspection frequency and ways to characterize failure.

Ideal Uses of Salt Mist

• Quality control of materials
• Accelerated corrosion testing

Strengths

• Fast
• Standardized

Limitations

• Sample dimensions 74*119*57 (b*h*d)
• No direct correlation between lifetime and degree of corrosion
• Test temperature = 50°C

Salt Mist Technical Specifications

• IEC 68-2-52 part 2:  Test Kb Salt mist, cyclic (sodium chloride solution)
• IEC 60068-2-11 part 2:  Test Ka Salt Mist
• ASTM B117 Standard Practice for Operating Salt Spray (Fog) Apparatus
• EN ISO 9227 Corrosion tests in Artificial atmospheres – salt spray tests
• EN ISO 7253 Paints & varnishes – determination of resistance to neutral salt spray (fog)
• EN 60512-11-6 Connectors for Electronic equipment – Tests and Measurements
• EN ISO 4541 Metallic and other non-organic coatings – Corrodkote (CORR) test
• DIN 50 021-CASS Copper Chloride Acetic Acid Salt Spray Test
• ISO 3769 Corrosion testing of metallic coatings – acetic acid salt spray test
• FORD FLTM BI 103-01 Salt Spray Resistance test for Painted Panels & Parts (Ford)
• GM4298P Salt spray / mist testing (General Motors)