An oxidative chloride stripping solution for 14K gold alloys

Kwangbae Kim, Ikgyu Kim, Ohsung Song

Research output: Contribution to journalArticlepeer-review


We propose a novel stripping solution containing acids (HCl and HNO3), an oxidant [(NH4)2S2O8], and complexing agents (NaCl and citric acid) to remove surface passivation layers from 14K gold alloys fabricated using an investment casting process. The optimized solution employing only HCl acid is determined by varying molar fractions of HCl and HNO3 on 14K yellow gold samples. Stripping properties are also identified for red and white gold alloy samples under the optimized stripping conditions. The removal of passivation layers, weight loss, and microstructure evolution are characterized using Raman spectroscopy, a precision scale, and optical microscopy. The proposed stripping solution effectively removes passivation layers more rapidly than conventional cyanide stripping. Weight loss increases linearly for up to 5 min for all 14K gold alloys. Red gold exhibits the greatest weight loss, followed by yellow gold and white gold. The results of microstructural analysis reveal that the conformal stripping occurs according to time. These results imply that the proposed oxidative chloride stripping might replace conventional cyanide stripping.

Original languageEnglish
Pages (from-to)393-398
Number of pages6
JournalKorean Journal of Materials Research
Issue number8
StatePublished - 1 Aug 2020


  • 14K gold alloy
  • Gold stripping
  • Oxidative chloride
  • Passivation layer


Dive into the research topics of 'An oxidative chloride stripping solution for 14K gold alloys'. Together they form a unique fingerprint.

Cite this