چكيده به لاتين
Bone china is a porcelain that contains at least 25% of bone ash. Increasing the amount of bone ash improves whiteness, translucency and mechanical strength of bone china body. On the other hand, considering that bone ash is an expensive part of the body, as well as its quality variability, makes it difficult to produce this monotonous product and requires new adjustments in the process of forming and sintering. Therefore, in this study, the physical and mechanical properties of bone china bodies prepared from synthetic bone powder have been investigated. In the first step, four types of hydroxyapatite with various sources of calcium and phosphorus including Ca(OH)2, CaCO3, H3PO4 and NH4H2PO4 were synthesized. The results of X-ray diffraction pattern and microstructure showed that the precipitates contained CaHPO4 and amorphous phases, which appeared after calcination around 800 °C of the hydroxyapatite phase and at 1200 °C this phase was complete and very small in size. In the next step, six bone china bodies with formulation of 20% feldspar, 30% kaolin and 50% of four types of synthetic powder were separately prepared and synthesized. To compare a formula with a natural bone, a formula was also made commercially synthesized with bone powder. The microstructural and phase studies showed that for all bodies, the main phases of β-tricalcium phosphate and anorthite, with a small amount of quartz phase, were formed in the matrix of the glass phase and the microstructures of the samples synthesized in this study were even better. In terms of physical and mechanical properties, the body containing bone powder and synthesized by Ca(OH)2 and NH4H2PO4 had the highest flexural strength (97.8 MPa) and balk density (2.64 g/cm3) and the lowest open porosity (0.35%) and water absorption (0.14%) after sintering at 1200 °C.
Keywords: Bone Chaina, β-Tricalcium phosphate, Anorthite, Hydroxyapatite, Bone ash.
