Confirming the cold diffusion bonding of gold in 19<sup>th</sup> century <i>kundan </i>settings

This paper investigates the microstructural features of Indian gold settings know as kundan using xenon plasma focused ion beam (pFIB), electron backscatter diffraction (EBSD) and energy dispersive x-ray spectroscopy (EDX). Testing sought to determine the purity of the gold foils in kundan settings and if they form diffusion bonds, by cold-working. Three, 19th century samples of Indian kundan with reliable provenance were analysed. The samples were from the hilts of two Indian daggers given as diplomatic gifts to Albert Edward, Prince of Wales, during his tour of the Indian subcontinent in 1875-6. It was confirmed that diffusion bonding does occur in the cold-worked gold during the kundan process. Work hardening and mechanical condensing also contribute to the mechanical integrity of kundan settings. The settings were found to comprise of near pure gold foils of ~10 µm thickness.