Properties of calcium-phosphate materials obtained by sol-gel method: effect of MgO concentration

Abstract A calcium-phosphate system was obtained by sol-gel method from 0.4 M solutions based on ethyl alcohol, tetraethoxysilane, phosphoric acid, calcium nitrate, and magnesium nitrate. Two compositions with different content of CaO and MgO were prepared. After the maturation of solutions they followed by heat treatment at 60°C for 30 minutes and at 600°C and 800°C for 1 h. Solution with 20 wt.% MgO is suitable for film production up to seven days, while 5 wt.% MgO is available for creation of films only on the second day of its preparation. Thin films were obtained on the second day by spin-coating with a centrifuge speed of 3000 rev/min, followed by heat treatment at 60°C for 20 minutes and at 800°C for 1 h. The formation of crystalline phases in synthesized materials occurs at 800°C. An increase in the content of magnesium oxide in the system helps to accelerate the growth of particles on the surface of the samples when immersed in a simulation body fluid