ultrasonic degreasing in isopropanol for 5-10 minutes.Sharma 4 reports the use of the following solutions for preplating of electroless nickel and gold on AZ31B magnesium alloy (3% aluminum, 1% zinc, 0.2% manganese by weight): For light green coatings the voltage was terminated at 64 VAC, for thick green coatings the voltage was terminated at 90 VAC.The other ingredients were added and the solution was heated to 82 ☌. Half the water was heated to 71 ☌ and NH4HF2 was slowly added.The chemicals were dissolved in the order given, then the bath was dummied with 1 square foot per gallon of magnesiumįor tan coatings the voltage was terminated at 64 VAC, for thick brown coatings the voltage was terminated at 85 VAC. clean with inhibited alkaline cleaner (Oakite 61A/45 g/l), for five minutes at 93 ☌ followed by cold water rinse.
Janssen 3 studied thermal reflectance of AZ31B and HK31A magnesium samples and reports the use of the following solutions: Published procedures and formulas for the finishing of magnesium. If cadmium or zinc must be used, chemically treat with a chromate or a phosphate coating. Select compatible aluminum alloys such as 50, for attachments and tin plated steel in preference to cadmium or zinc.Allow for dimensional growth in protective coatings for magnesium except for dichromate or chrome pickle treatments.Avoid sharp corners during design of the component.The quality and thickness of organic coatings is most important in mating areas of dissimilar metals.To minimize the corrosion potential between magnesium and dissimilar metals, the area of the magnesium should be large compared to the area of the dissimilar metal.Vinyl and epoxy resins for organic coatings since the corrosion products of magnesium are highly alkaline in nature, thus acting as a stripper for many commonly used organic primers and enamels.He recommends Dow 17 or HAE anodize (Mil-M-45202 Type I Class A) and Type I Class C, respectively, or Conversion coating (DOW 7 (Mil-M-3171 Type III or VIII) or or DOW 19 (Mil-M-3171 Type VI). Groshart 1 states that magnesium must be passivated before painting. Review of early prepaint cleaning and activation of magnesium. Magnesium is usually treated with chromate conversion coatings or an anodize finish prior to the application of organic finishes. Pullizzi, Bayside Electrical Testing, Inc., Beach Haven, NJ
0 kommentar(er)
