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Title: Method for regeneration of electroless nickel plating solution

An electroless nickel(EN)/hypophosphite plating bath is provided employing acetic acid/acetate as a buffer and which is, as a result, capable of perpetual regeneration while avoiding the production of hazardous waste. A regeneration process is provided to process the spent EN plating bath solution. A concentrated starter and replenishment solution is provided for ease of operation of the plating bath. The regeneration process employs a chelating ion exchange system to remove nickel cations from spent EN plating solution. Phosphites are then removed from the solution by precipitation. The nickel cations are removed from the ion exchange system by elution with hypophosphorous acid and the nickel concentration of the eluate adjusted by addition of nickel salt. The treated solution and adjusted eluate are combined, stabilizer added, and the volume of resulting solution reduced by evaporation to form the bath starter and replenishing solution.
Inventors:
 [1]
  1. (5423 Vista Sandia, NE., Albuquerque, NM 87111)
Issue Date:
OSTI Identifier:
870856
Assignee:
Eisenmann, Erhard T. (5423 Vista Sandia, NE., Albuquerque, NM 87111) SNL
Patent Number(s):
US 5609767
Contract Number:
AC04-76DP00789
Research Org:
AT & T CORP
Country of Publication:
United States
Language:
English
Subject:
method; regeneration; electroless; nickel; plating; solution; hypophosphite; bath; provided; employing; acetic; acid; acetate; buffer; result; capable; perpetual; avoiding; production; hazardous; waste; process; spent; concentrated; starter; replenishment; ease; operation; employs; chelating; exchange; remove; cations; phosphites; removed; precipitation; elution; hypophosphorous; concentration; eluate; adjusted; addition; salt; treated; combined; stabilizer; added; volume; resulting; reduced; evaporation; form; replenishing; plating solution; resulting solution; nickel plating; regeneration process; acetic acid; hazardous waste; process employs; plating bath; nickel salt; bath solution; electroless nickel; generation process; /210/106/