Abstract
The mechanical properties and processing of a newly developed ternary Au-Sb-Co alloy with 995 fineness are discussed. The high gold content of this alloy (99.5 per cent) facilitates marking as 24 carat gold (orChuk Kam) in many countries. The alloy has a rich yellow colour, virtually identical to that of pure gold, and can be hardened to a peak hardness of 130 to 140 points on the Vickers hardness scale using a combination of cold work and a low temperature (250 to 300°C) ageing heat treatment. This hardness is comparable to that of cold-worked 22 carat yellow gold, and almost double the maximum hardness that can be obtained in pure gold. The 995 alloy is highly formable, and is amenable to casting, granulation, remelting, wire drawing, forming and rolling.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
A. Nishio,Gold Technol., July 1996,19, 11
Gold 1995, Gold Fields Mineral Services Ltd, May 1995, 52
T. Green, Gold News, July-August 1992, 1
R. Sitt, American Metal Market - Gold, 9 November 1993, 8
G. Gafner,Gold Bull., 1989,22(4), 112
C.W. Corti,Gold Bull., 1999,32(2), 39
ASM Handbook: Alloy Phase Diagrams, 3, ASM International, Metals Park, OH 44073-0002, 1992, 2.67 (Au-Sb Binary Phase Diagram), 2.75 (Au-Co Binary Phase Diagram)
M. Coetzee, unpublished data, July 1995
C. Raub and D. Ott, Proceedings of the Symposium on the Industrial Uses of Gold, Gold 100, Johannesburg, 1986,3, 65–72
M. du Toit, Proceedings of the Santa Fe Symposium on Jewelry Manufacturing Technology, 1997, 381–394
Gold Alloy Data,Gold Technol., January 1990,1, 6
Author information
Authors and Affiliations
Additional information
Dr Madeleine du Toit is a professional engineer and metallurgist currently employed as Senior Lecturer in the Department of Materials Science and Metallurgical Engineering at the University of Pretoria, South Africa. Her responsibilities include teaching and research in the fields of physical metallurgy and welding engineering. Prior to joining the University of Pretoria, she was with the Physical Metallurgy Division of Mintek, where she specialised in the metallurgy of gold alloys.
Dr Elma van der Lingen heads the Precious Metals Group in the Physical Metallurgy Division of Mintek. Rainer S?ss is a Senior Engineer and Lizelle Glaner is a Senior Technician in the same group.
Rights and permissions
About this article
Cite this article
du Toit, M., van der Lingen, E., Glaner, L. et al. The Development of a Novel Gold Alloy with 995 Fineness and Increased Hardness. Gold Bull 35, 46–52 (2002). https://doi.org/10.1007/BF03214837
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF03214837