Flaky Cadmium
Question: Our company plates small parts used in the aircraft industry.
Question:
Our company plates small parts used in the aircraft industry. We have successfully plated cadmium for more than 10 years but recently started having problems. The bath was changed late last year, and shortly after that we started seeing flaking and adhesion failure using a bend test. We also observed that the parts require longer times to plate with this new solution compared to the old discarded solution. The parts and test coupons are barrel plated. The failures are not consistent. What can cause this problem? (Additional information on the process was included with the e-mail.) S.C.
Answer:
The problem reared its ugly head after the cadmium plating solution was changed. This is where you should start your troubleshooting. Excess brightener in the plating bath can cause peeling and poor adhesion. Another cause can be improper acid dipping of the parts. This can cause hydrogen absorption, which can cause peeling. The problem with the longer plating times can be caused by a plating bath with too high a cyanide concentration or a low metal content.
Also determine if everything is okay with your barrels and danglers. Were they changed or modified during the same time period? Are all electrical contacts clean and free of corrosion?
In short, do a thorough inspection of the entire cadmium plating process. Do it when you are wide awake! You have a better chance of spotting problems when “bright-eyed and bushy-tailed!” Get a copy of Trouble in Your Tank, 3rd Edition, by Lawrence J. Durney available from Products Finishing Hanser Gardner Publications, 800-950-8977. The book can be a tremendous help.
RELATED CONTENT
-
Plating Q&A: Can you color stainless steel?
Our expert, Art Kushner, says yes, you can color stainless steel, but it is not a process that is typically performed in a plating shop. Read more about his answer.
-
Masking for Surface Finishing
Masking is employed in most any metal finishing operation where only a specifically defined area of the surface of a part must be exposed to a process. Conversely, masking may be employed on a surface where treatment is either not required or must be avoided. This article covers the many aspects of masking for metal finishing, including applications, methods and the various types of masking employed.
-
Smut and Desmutting
Question: I am new to this industry and have heard about smut and desmutting operations.