Porous Apatite Ceramics Derived from Woods

Porous calcium phosphate ceramics (apatite and TCP) with wood-like microstructures, analogous to that of silicified wood, were prepared from natural woods as templates. The production of these ceramic woods was performed by the following process: (1) infiltration with an ethanol solution containing tri-ethyl phosphate and calcium nitrate tetra-hydrate into wood specimens, (2) drying to form a calcium phosphate gel in the cell structure, (3) firing in air to form apatite and TCP. The microstructure of the obtained ceramic woods retained the same structure as that of the raw woods: with the pore sizes corresponding to those of the original wood, and the major pores being unidirectionally connected.

The Investigation on Preparation & Physicochemical Process of Nanosized Hydroxyapatite Powder

The investigations of the preparation and physicochemical process of the HA nanostructured powder with high performance have been performed at present study. The HA preparation starts from the ethanol solution of calcium nitrate tetra-hydrate and phosphorous pentoxide as raw materials. The characterization of the effects of reacting temperatures on preparation, the crystalline degrees (some amorphous HA formed at certain condition) of the reacting products are carried out in the meanwhile. The physicochemical processes and the conditions for different reactions stages of the HA preparation have been traced and characterized by the TG-DTA (thermogravimetric and differential thermal analysis), the FTIR (Fourier-transformed infrared spectroscopy) and other methods. The investigations of the chemical reactions for the HA preparation show that the synthesis of HA is completely finished at the temperature of 500°for hours. The grain sizes and shapes of the HA reacting products are observed and characterized by the TEM and the XRD. The results show that the mean diameters of these product grains are as fine as 30-40nm at the temperature of 500°C. The XRD pattern of the present HA powders sintered at 500°C for 2h coincided very well with the JCPDS standards showing its superior purity and therefore, with really high performance for later applications.