Hydroxyapatite and Other Calcium Phosphates for the Conservation of Cultural Heritage: A Review

Sassoni, Enrico (2018) Hydroxyapatite and Other Calcium Phosphates for the Conservation of Cultural Heritage: A Review. Materials, 11 (4). pp. 1-48. ISSN 1996-1944
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The present paper reviews the methods and the performance of in situ formation of calcium phosphates (CaP) for the conservation of materials belonging to cultural heritage. The core idea is to form CaP (ideally hydroxyapatite, HAP, the most stable CaP at pH > 4) by reaction between the substrate and an aqueous solution of a phosphate salt. Initially proposed for the conservation of marble and limestone, the treatment has been explored for a variety of different substrates, including sandstones, sulphated stones, gypsum stuccoes, concrete, wall paintings, archaeological bones and paper. First, the studies aimed at identifying the best treatment conditions (e.g., nature and concentration of the phosphate precursor, solution pH, treatment duration, ionic and organic additions to the phosphate solution, mineralogical composition of the new CaP phases) are summarized. Then, the treatment performance on marble and limestone is reviewed, in terms of protective and consolidating effectiveness, compatibility (aesthetic, microstructural and physical) and durability. Some pilot applications in real case studies are also reported. Recent research aimed at extending the phosphate treatment to other substrates is then illustrated. Finally, the strengths of the phosphate treatment are summarized, in comparison with alternative products, and some aspects needing future research are outlined.

Document type
Sassoni, EnricoUniversity of Bologna, Italyorcid.org/0000-0003-0716-510X
marble limestone consolidation protection durability calcium phosphates hydroxyapatite octacalcium phosphate ammonium phosphate ammonium oxalate
Deposit date
25 May 2018 08:33
Last modified
23 May 2019 09:13
Project name
HAP4MARBLE - Multi-functionalization of hydroxyapatite for restoration and preventive conservation of marble artworks
Funding program
EC - H2020

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