1 Scope
This document specifies the application of the cyclic salt mist test to components or equipment designed to withstand a salt-laden atmosphere as salt can degrade the performance of parts manufactured using metallic and/or non-metallic materials.
This document is applicable to components or equipment that can withstand salty atmosphere, and the corresponding severity level is selected according to the degree of tolerance during the test.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 9227 Corrosion tests in artificial atmospheres - Salt spray tests
IEC 60068-1 Environmental testing - Part 1: General and guidance
IEC 60068-2-78 Environmental testing - Part 2-78: Tests - Test Cab: Damp heat,steady state
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
IEC Electropedia: available at http://www.electropedia.org/
ISO Online browsing platform: available at http://www.iso.org/obp
4 General description of test
4.1 Description of each test condition
4.1.1 General
This document consists of the cyclic test conditions of salt mist, dry condition, humid condition and standard atmosphere. The effect of each test condition is as follows.
Note: Salt mist is also called salt spray.
The test specimen(s) is typically not energized during the test.
4.1.2 Salt mist
The test specimen is corroded by an electrochemical or complex chemical reaction with neutral or acidified salt solution. Salt solution forms a thin electrolytic film on the test specimen surface. This can initiate corrosion and can allow it to proceed.
4.1.3 Dry condition
Heated air in the chamber may cause evaporation of water from the test specimen surface from decreasing relative humidity and increased specimen temperature. This causes the concentration of the solution to increase and speeds up chemical reactions, accelerating the corrosion process. Salt precipitates out of the solution onto the test specimen surface during this condition. Evaporation and heating rates may vary based on the test chamber and test specimen.
4.1.4 Humid condition
4.1.4.1 Dry condition to humid condition
As the relative humidity increases, precipitated salt crystals on the specimen surface absorb water vapour until a liquid electrolytic solution forms, reinitializing the corrosion process.
4.1.4.2 Salt mist to humid condition
The humid condition maintains the existing wetness on the test specimen surface at the end of the salt mist period, without excessive dilution of the solution that may result from condensing humidity.
4.1.5 Standard atmosphere
The test specimen is allowed to equilibrate with standard laboratory conditions, which results in gradual drying and relaxation from most corrosion reactions. The period of dry atmosphere may occur, in practice, during breaks of operation, for example during the weekend. The inclusion of such a dry period may lead to corrosion mechanisms which can be quite different from those under constant wet conditions. The test schedule shall be chosen in order to respect the timelines given in 9.4. Additional dry periods (e.g. during a weekend) shall be avoided.
Foreword I
Introduction III
1 Scope
2 Normative references
3 Terms and definitions
4 General description of test
5 Test apparatus
6 Salt solution
7 Initial measurements
8 Preconditioning
9 Testing
10 Recovery (at the end of testing)
11 Final measurements
12 Information to be given in the relevant specification
13 Information to be given in the test report
Annex A (Informative) Typical apparatus for cyclic salt mist, humid condition, dry condition and standard atmosphere corrosion tests
Annex B (Informative) Description of each test method
Annex NA (Informative) The components of the standard GB/T
Bibliography
Figure A.1 Example of test apparatus
Table 1 Test cycles for test methods 1 to
