Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/04—Electroplating: Baths therefor from solutions of chromium
  • C25D3/10—Electroplating: Baths therefor from solutions of chromium characterised by the organic bath constituents used
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/04—Electroplating: Baths therefor from solutions of chromium
  • C25D3/06—Electroplating: Baths therefor from solutions of chromium from solutions of trivalent chromium

Definitions

• electrolyte is substantially free of hexavalent chromium salts.
• Amino acids fall into several groups as shown in Figure 1.
• the amino acids methionine and cysteine (and cystine) contain bivalent sulphur in their side chains.
• the use of these sulphur-containing compounds as darkening agents in trivalent chromium baths has been previously disclosed, as for example in WO 2012/150198A1 to Schulz et al., which is hereby incorporated herein by reference in its entirety. This is understood to be a function of the presence of sulfur in the compound, as sulfur is known to cause darker hues in trivalent chromium deposits as compared to the more pure deposits produced from hexavalent chromium electrolytes.
• inert anodes such as carbon anodes
• inert anodes such as carbon anodes
• Other inert anodes such as platinized titanium, platinum, iridium oxide coated titanium, or tantalum oxide coated titanium may also be used.
• the trivalent chromium electrolyte used as a standard is an electrolyte designed to produce light colored chromium deposits.
• the electrolyte and plating process is based on U.S. Patent No. 4,473,448 to Deeman. This patent is hereby incorporated by reference in its entirety.
• the average reduction in L* value was 12.7% using the examples of the invention of arginine and histidine. This is a significant difference which can easily be seen by eye.
• the addition of arginine, histidine or lysine gave uniform color across the entire deposit.
• the addition of tryptophan gave a dramatic effect but produced very uneven and streaky deposits, which although significantly darker, were commercially unacceptable.
• Table 4 gives the L* values obtained when amino acids of the invention are added to the electrolyte based on U.S. Patent No. 4, 161 ,432 to Barclay et al. This electrolyte was used as the Standard (2) to compare the L* values after the amino acids are added. As previously noted, deposits produced using this electrolyte process were previously formulated to provide dark colored trivalent chromium deposits.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Electroplating And Plating Baths Therefor (AREA)
• Electroplating Methods And Accessories (AREA)

Applications Claiming Priority (2)

Publications (2)

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• 2016
  • 2016-04-21 US US15/134,469 patent/US20170306515A1/en not_active Abandoned
• 2017
  • 2017-04-11 JP JP2018555269A patent/JP2019516016A/ja active Pending
  • 2017-04-11 KR KR1020187033624A patent/KR20180137531A/ko not_active Ceased
  • 2017-04-11 CA CA3020402A patent/CA3020402A1/en not_active Abandoned
  • 2017-04-11 BR BR112018071355A patent/BR112018071355A2/pt not_active Application Discontinuation
  • 2017-04-11 EP EP17786348.7A patent/EP3443145A4/de active Pending
  • 2017-04-11 CN CN201780024363.0A patent/CN109154092A/zh active Pending
  • 2017-04-11 MX MX2018012675A patent/MX2018012675A/es unknown
  • 2017-04-11 WO PCT/US2017/026951 patent/WO2017184380A1/en not_active Ceased
  • 2017-04-20 TW TW106113202A patent/TWI636161B/zh active

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