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[PDF] Japanese irogane alloys and patination

Japanese irogane alloys and patination – a study of production and

O’DUBHGHAILL, C. and JONES, A. H. (2009). Japanese irogane alloys
and patination – a study of production and application. In:
Proceedings of the Twenty-Third Santa Fe Symposium on Jewelry
Manufacturing Technology, Albuquerque, New Mexico, May 2009.
Met-Chem Research.

Japanese metalworkers use a wide range of irogane alloys (shakudo,
shibuichi), which are colored with a single patination solution
(niiro). This approach allows different alloys to be combined in one
piece and patinated, producing a multi-colored piece of metalwork.

At present the production of irogane alloys and their patination is
an unreliable process. This study aims to develop reliable alloy
production and a safe, easy-to use and repeatable patination process
using standard ingredients available from chemical suppliers.

The study has examined the production of shakudo and shibuichi
alloys, characterizing the alloys produced by casting into cloth
molds in hot water, into steel molds, and produced using continuous
casting. The influence of traditional polishing methods was assessed
using surface texture (Sa) measurements. Traditional rokusho, an
ingredient of the niiro solution, was analyzed by XRF and XRD. Niiro
patinated surfaces on a range of alloys were examined using XRD and
Lab* color measurements.

Here is the link to the paper:

The second paper we published on this area of research is here: