Consolidating effect of hydroxyapatite on the ancient ivories from Jinsha ruins site: Surface morphology and mechanical properties study

In this study, the ancient ivories from Jinsha ruins site have been consolidated through impregnation in aqueous hydroxyapatite (HAP) colloid prepared by the hydrothermal method. Microscopic examinations and nano-indentation/scratch tests were conducted to characterize the morphology and mechanical properties of ivory's surface. After the consolidation treatment, a compact HAP nano-particle layer is formed on the original ivory surface, and the loose and porous surface is repaired. The hardness, elastic modulus, and anti-scratch performance of the repaired ivory surface are significantly improved. Also, the consolidated surface acts as a protective layer, which isolates the ivory from the ambient environment and avoids further deterioration. The consolidation has compatible aesthetics, and does not introduce extraneous substances into the ivory. The results have shown nano-HAP is a promising consolidant for ancient ivories.