Development of High-Strength 96.5% Gold for Sustainable Jewelry Product Design

Abstract

This study aims to develop high-strength 96.5% pure gold with enhanced hardness and durability in order to expand its potential for contemporary jewelry product design, while maintaining its purity, color, and aesthetic qualities, in alignment with the concept of sustainable design. The experimental process involved the incorporation of alloying elements—germanium powder, titanium powder, and graphene powder—at 0.1 wt% into 96.5% gold through melting and subsequent fabrication into sheet samples. The materials were evaluated for mechanical properties, including Vickers hardness and tensile strength, as well as microstructural characterization and alloying element distribution using FESEM-EDS analysis, and optical properties through CIELAB color coordinate measurement. The results indicate that germanium provided the most significant improvement, increasing hardness by 11.43% and enhancing tensile strength compared to the control sample. FESEM-EDS analysis revealed that germanium was uniformly distributed throughout the material, contributing to improved mechanical properties, whereas graphene exhibited agglomeration, resulting in reduced hardness. Color analysis showed that the addition of alloying elements caused only minor color changes (DE* ranging from 1.96 to 3.11), with the samples retaining color characteristics close to standard 96.5% gold. In terms of sustainability, a prototype 96.5% gold ring was developed and its carbon footprint was assessed following Cradle-to-Gate life cycle assessment principles, showing low greenhouse gas emissions of 1.4789 kgCO2e. The findings highlight the role of material innovation in supporting the design of more diverse, complex, and functional contemporary jewelry products, while demonstrating the integration of material development with sustainable design principles, offering practical applications for product design and the jewelry industry in the future.