RHEOLOGY OF TRICALCIUM PHOSPHATE (β-TCP) SUSPENSIONS

956 Maria Spătaru et al.shear rate, γ . The flow behaviour depends on thecomposition and stability of the suspensions.Due to the fact that in the literature data there areonly few pieces of information about the aqueoussuspensions of β-TCP and their rheologicalcharacterization, respectively, the purpose of thispaper is to obtain β-TCP aqueous suspensions withdifferent additives and to evaluate them fromrheological point of view.RESULTS AND DISCUSSIONβ-TCP powderThe β-TCP powder prepared in the experimentalconditions presented further was characterised formstructural and morphological point of view.The XRD pattern is shown in Fig. 1.The pattern shows an excellent agreement withthe published JCPDS files for β-TCP.The FTIR spectrum of tricalcium phosphatesample is shown in Fig. 2.The range of 800 – 1200 cm -1 exhibits a wideabsorption band typical of tetrahedral anions XO 4 n ,in particular, PO 4 3- . FTIR analysis demonstratedPO 4 3– adsorption peaks around 1040-1122; 610,and 551 cm –1 attributable to ß-TCP. 5, 6 FTIRspectrum of sintered beta-tricalcium phosphateshowed typical spectrum for TCP material. Thecharacteristic phosphate peaks for β-TCP at wavenumbers of 1122,5- 1045,3; 609,5 and 551,6 cm -1were present. The band at position of 1436,9 cm -1is probably from carbonate, which is commonlyfound in both synthetic TCP and natural bone. 7SEM micrograph of pure β-TCP powder, sinteredat 1150 0 C for two hours, is shown in Fig. 3.Intensity, [a.u.]β-TCP10 20 30 40 50 602 θFig. 1 – XRD pattern of the β-TCP powder, sintered at 1150 °C/2h .Fig. 2 – IR spectrum of the β-TCP powder, sintered at 1150 ºC for 2h.