| NASF Education Director
Corrosion & Salt Spray Course
The course consists of 7 lessons. Students successfully completing the exam will be given credit towards the Master Surface Finishers (MSF) certification. While it is not necessary to take any course to be eligible to sit for the respective exam that could lead you to becoming a Master Surface Finisher (MSF), this course covers one of the optional subject areas for qualifying to obtain MSF certification.
This training program is designed to be beneficial for operators of accelerated corrosion test and supervisors of metal finishing job shop and captive shops that have in-house corrosion testing capability or that farm such testing to outside laboratories. The course is also beneficial to sales personnel serving the metal finishing industry, as it will provide a level of knowledge about the corrosion resistance of various coatings that will allow a better understanding of the needs of their customers.
Trainees should have at minimum a high school diploma. The training materials and instruction are in English. In many cases, metric and/or US/English units of measurement are utilized. Students are taught how to convert between the two systems of measurement when required.
The goal of this course is to provide the student with a general knowledge of common corrosion mechanisms and how they are employed in accelerated corrosion tests. Students will also know best operating practices for conducting accelerated corrosion testing.
At the conclusion of this course, attendees should:
- Have knowledge of the basic corrosion mechanisms involved in accelerated corrosion tests
- Be able to understand galvanic corrosion series in sea water and acid rain
- Know the levels of corrosion protection afforded by commonly applied electroplated deposits
- Have knowledge of the equipment used for salt spray and other accelerated corrosion tests, along with bets operating practices
- Know how to properly prepare test specimen for accelerated corrosion test exposure
- Be aware of and have a basic understanding of the differences between the common alternative accelerated corrosion tests such as CASS, Corrodkote, Acetic Acid and Kesternich tests
- Be able to identify and correct the most commonly encountered causes of salt spray failures
- Be prepared to take the examination, which is part of the Foundation MSF certification program
- 1. Corrosion Principles, Tests & Design for Corrosion Protection, Part 1
- This lesson begins by identifying the most common mechanisms for the on-set of corrosion. The lesson then describes the galvanic/Electromotive Force Series of metals and how they apply to corrosion of plated parts. The concept of galvanic corrosion cells is further developed to include stressed metal corrosion mechanisms. Students are taught how these mechanisms are incorporated into accelerated corrosion test chambers. How various coatings may or may not afford sacrificial corrosion protections is a main focus of this lesson.
- 2. Corrosion Principles, Tests & Design for Corrosion Protection, Part 2
- In part 2 of this lesson, differential oxygen concentration corrosion, fretting corrosion, and stress corrosion cracking are covered. A secondary focus of this lesson is the design factors that go into a part that successfully resists (or fails) corrosion tests. The lesson also covers ASTM B456 requirements for electroplated copper-nickel-chromium deposits.
- 3. Equipment for Salt Spray Testing
- This lesson provides equipment guidelines for conducting accelerated corrosion testing with a focus on the salt spray test. Each major component, from the cabinet to the spray nozzle is described in detail along with a discussion of the differences in design between various suppliers.
- 4. Salt Spray Cabinet Maintenance & Operation
- This lesson provides a detailed look at operational conditions that can affect the test results. Special attention is given to monitoring of the chamber conditions and record keeping.
- 5. Preparing, Exposing & Evaluating Parts
- This lesson covers the most often mentioned question with salt spray testing; “how should parts be masked, exposed and evaluated?” Numerous examples are provided. Students are also taught how to handle parts before and after testing, and how they can best train themselves to recognize a certain percentage of surface area that has corroded during the test.
- 6. Alternate Accelerated Corrosion Tests
- This lesson provides basic information on other accelerated corrosion tests such as CASS, Corrodkote, Acetic Acid, and Kesternich tests, with a special focus on the increasingly popular CASS (Copper Accelerated Slat Spray) test. An important part of this lesson is how to conduct a corrosivity test on a CASS test chamber. Equipment and operational differences between the alternate and the salt spray test are also given.
- 7. Salt Spray Failures
- The salt spray test may indicate a failure of a coating, even when the coating has been properly applied. This is most commonly found on aluminum test panels that have been conversion coated and on sulfuricboric anodized aluminum test panels processed per aerospace specifications. This lesson goes over potential causes of failures that include problems in conducting the test, problems with the test panels and problems on the processing lines. The lesson focuses heavily on operational conditions that might be overlooked—wrong exposure angle, for example.