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Title: Method for regeneration of electroless nickel plating solution

Abstract

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 hypophosphorus 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. 1 fig.

Inventors:
Publication Date:
Research Org.:
AT&T Corporation
OSTI Identifier:
445702
Patent Number(s):
US 5,609,767/A/
Application Number:
PAN: 8-241,234
Assignee:
SNL; SCA: 320305; 320302; PA: EDB-97:040791; SN: 97001749870
DOE Contract Number:
AC04-76DP00789
Resource Type:
Patent
Resource Relation:
Other Information: PBD: 11 Mar 1997
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; PROCESS SOLUTIONS; METAL INDUSTRY; REGENERATION; RECYCLING; NICKEL; PLATING; CHELATING AGENTS; ION EXCHANGE; PRECIPITATION

Citation Formats

Eisenmann, E.T.. Method for regeneration of electroless nickel plating solution. United States: N. p., 1997. Web.
Eisenmann, E.T.. Method for regeneration of electroless nickel plating solution. United States.
Eisenmann, E.T.. 1997. "Method for regeneration of electroless nickel plating solution". United States. doi:.
@article{osti_445702,
title = {Method for regeneration of electroless nickel plating solution},
author = {Eisenmann, E.T.},
abstractNote = {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 hypophosphorus 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. 1 fig.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1997,
month = 3
}
  • 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 hypophosphorousmore » 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.« less
  • This invention is an improved method for conducting electroless metal-plating processes in a metal tank which is exposed to the plating bath. The invention solves a problem commonly encountered in such processes: how to determine when it is advisable to shutdown the process in order to clean and/or re-passivate the tank. The new method comprises contacting the bath with a current-conducting, non-catalytic probe and, during plating operations, monitoring the gradually changing difference in electropotential between the probe and tank. It has been found that the value of this voltage is indicative of the extent to which nickel-bearing decomposition products accumulatemore » on the tank. By utilizing the voltage to determine when shutdown for cleaning is advisable, the operator can avoid premature shutdown and at the same time avoid prolonging operations to the point that spontaneous decomposition occurs.« less
  • An improved method for conducting electroless metal-plating processes in a metal tank which is exposed to the plating bath is described. A problem commonly encountered in such processes: how to determine when it is advisable to shutdown the process in order to clean and/or re-passivate the tank is solved. The new method comprises contacting the bath with a current-conducting, non-catalytic probe and, during plating operations, monitoring the gradually changing difference in electropotential between the probe and tank. It has been found that the value of this voltage is indicative of the extent to which nickel-bearing decomposition products accumulate on themore » tank. By utilizing the voltage to determine when shutdown for cleaning is advisable, the operator can avoid premature shutdown and at the same time avoid prolonging operations to the point that spontaneous decomposition occurs.« less
  • This invention is an improved method for conducting electroless metal-plating processes in a metal tank which is exposed to the plating bath. The invention solves a problem commonly encountered in such processes: how to determine when it is advisable to shut down the process in order to clean and/or re-passivate the tank. The new method comprises contacting the bath with a current-conducting, non-catalytic probe and, during plating operations, monitoring the gradually changing difference in electropotential between the probe and tank. It has been found that the value of this voltage is indicative of the extent to which nickel-bearing decomposition productsmore » accumulate on the tank. By utilizing the voltage to determine when shutdown for cleaning is advisable, the operator can avoid premature shutdown and at the same time avoid prolonging operations to the point that spontaneous decomposition occurs. 1 figure.« less