Invention Grant
- Patent Title: Enhanced techniques for production of golden bronze by inter-diffusion of tin and copper under controlled conditions
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Application No.: US14441740Application Date: 2012-11-08
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Publication No.: US10266959B2Publication Date: 2019-04-23
- Inventor: Taixiang Jiang , Sridhar Bushigampala , Xianyao Li
- Applicant: Monnaie Royale Canadienne / Royal Canadian Mint
- Applicant Address: CA Ottawa (Ontario)
- Assignee: MONNAIE ROYALE CANADIENNE / ROYAL CANADIAN MINT
- Current Assignee: MONNAIE ROYALE CANADIENNE / ROYAL CANADIAN MINT
- Current Assignee Address: CA Ottawa (Ontario)
- Agency: BakerHostetler
- International Application: PCT/CA2012/050795 WO 20121108
- International Announcement: WO2014/071493 WO 20140515
- Main IPC: C25D5/50
- IPC: C25D5/50 ; C25D5/10 ; C25D3/30 ; C25D3/38 ; A44C21/00 ; B32B15/01 ; C22F1/00 ; C25D5/34 ; C23F1/00 ; C23F17/00 ; C25D3/22 ; C25D5/52

Abstract:
Golden bronze appearance article, multiple-layer substrate, related methods and uses thereof, particularly for coinage blanks. Methods of producing an article having a golden bronze appearance include annealing a multiple-layer substrate at an annealing temperature for an annealing residence time. The multiple-layer substrate includes a core, contiguous to a copper layer and subsequent tin layer. The annealing temperature and annealing residence time are controlled in accordance with each other for allowing diffusion of the tin layer into the copper layer and producing an annealed substrate comprising an inter-diffused outer bronze layer having a golden appearance. The tin layer thickness is in accordance to the copper layer thickness such that the inter-diffused outer bronze layer has a tin content between about 8% wt. and about 15.8% wt. The core has a sufficiently low content of nickel to reduce or prevent formation of intermetallic compound comprising tin and nickel proximate to the core during annealing.
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