Moreover, IC analysis of the water solution showed that nitrate ions were released. For the same reason the spectra of 0.7ZrO2·0.3HAp and 0.5ZrO2·0.5HAp samples (Figure 1d,e) are also very similar to the Ca(NO3)2·4H2O spectrum, whereas the spectrum of the 0.9ZrO2·0.1HAp (Figure 1...