Double Substituted Carbonated Hydroxyapatite for Stone Consolidation

Abstract

This paper aims with the preparation of Sr2+ and Zn2+ double substituted carbonated hydroxyapatite (Sr-Zn-CHAp) by the nanoemulsion method and to evaluate its consolidation capacity on artificial stone samples. The changes in CHAp lattice parameters were observed by a synergy between the shrinkage and dilatation induced by the two metallic ions, with different ionic radii by comparison with calcium. The changed morphology obtained by calcination was evidenced by SEM analysis. Also, the tendency to agglomerate of the double substituted CHAp as micron- and sub-micron-sized particles with spherical and irregular form was observed. The FTIR, XRD and EDS results confirmed that the CHAp was successfully substituted with Sr2+ and Zn2+ by replacing Ca2+ resulting a AB-type CHAp. The efficacity of Sr-Zn-CHAp as inorganic consolidant for the stone was tested by mechanical strength, resistance at freeze–thaw artificial aging test, thermal shock weathering, colorimetric changes of the artificial stone sample, all the results being correlated with the water absorption test, water repellency, and pore structure changes. By treating the stone with 0.5 g/L Sr-Zn-CHAp led to an improvement of the above-mentioned characteristics, without significant chromatic changes.

Double-Substituted Carbonated Hydroxyapatites for Fir Wood Treatment

“…The specimen's dimensions were similar for the two types of wood, of about 3x3 cm for YF and 2x5 cm for 30F, Figure 1. Double-substituted carbonated hydroxyapatite was synthetized according to [19,20]. In order to study the influence of the consolidate amount on the variation of wood properties, the samples were treated by brushing with the three suspensions, of 0.1 g/L, 0.25 g/L, and 0.5 g/L respectively from every powder.…”

“…Among these solutions, hydroxyapatite (HAp) can be also considered as an useful consolidating agent for wood and other materials like paper or stone [15]. Despite that, it is known that HAp has a relative low mechanical resistance and a way to increase this characteristic consists in obtaining apatite materials having in their structure magnesium ions, silver, barium, zinc and copper [16][17][18][19][20]. Carbonated hydroxyapatite (CHAp) powder presents better homogeneity and consolidating efficacy, especially as nano sized [21].…”

“…The inorganic compounds contain zinc as main metallic ion and magnesium and strontium ions as the second path of calcium substitution. The synthesis method previous reported for Sr-Zn-CHAp [20] will be used for Mg-Zn-CHAp obtaining and, after its characterization, the wood samples will be treated by brushing with three different concentration of consolidant and tested.…”

New Triple Metallic Carbonated Hydroxyapatite for Stone Surface Preservation

“…Also, some selected consolidants, Ag-CHAp and Sr-CHAp, proved good consolidation efficacy when applied to the damaged area of some real samples with heritage value [20]. Under this context, double-substituted carbonated hydroxyapatite has been prepared and characterized [21]. A similar conformation of the apatite structure resulted from the simultaneous replacement of Ca 2+ with strontium and zinc, the obtained Sr-Zn-CHAp structure presenting an appropriate behavior in stone consolidation processes.…”

Diagnosis, Photogrammetry and Conservation Treatment with Nanomaterials of Sacidava Fortress

“…In this paper, several samples from the Sacidava Fortress are analyzed, in order to identify the origin of the raw materials and the deterioration processes that took place at this monument. Many nanomaterials have been used up to date for chemical consolidation and antimicrobial restoration of different surfaces from everywhere in the world [7][8][9][10][11][12][13]. In Chem.…”