title: Combined effect of magnesia and zirconia on the bioactivity of calcium silicate ceramics at C\S ratio less than unity.
abstract: This paper describes the effect of magnesia in the presence of zirconia on the bioactivity, microstructure and physico-mechanical properties of calcium silicate composition adjusted at calcia/silica ratio(C/S) of 0.5. A mixture from calcium carbonate and silica was conducted at C/S of 0.5. 20wt.% of magnesia and 5-25wt.% of ZrO2were added. Each mixture was mixed with ethanol in a planetary ball mill, dried, formed and fired at a temperature of 1325±5°C. Phase composition, FE-SEM, and physico-mechanical properties of the fired specimens were determined and explained. The in vitro bioactivities of these specimens were investigated by analysis of their abilities to form apatite in the simulated body fluid (SBF) for a short time (7days) using SEM-EDS. The findings indicated that the surface of the specimens containing 5 and 15wt.% ZrO2were completely covered by single and multilayered hydroxyapatite (HA) precipitate typical to "cauliflower" morphology, respectively. The surface of the specimen containing 25wt.% ZrO2did not cover, but there are some scattered HA precipitate. The differences among the results were rationalized based on the phase composition. Vickers hardness and fracture toughness of the specimens of highly promised bioactivity were 2.32-2.57GPa and 1.80-1.50MPa. m1/2, respectively. The properties of these specimens are similar to the properties of human cortical bone. Consequently, these composites might be used as bone implant materials.
authors: Refractory & Ceramic Materials Division (RCMD), Advanced Materials Department, Central Metallurgical R&D Institute (CMRDI), P.O. Box 87, Helwan, 11421, Cairo, Egypt. Electronic address: dr_ewais@hotmail.com.
authors: Emad M M
authors: EM
authors: Ewais
authors: Refractory & Ceramic Materials Division (RCMD), Advanced Materials Department, Central Metallurgical R&D Institute (CMRDI), P.O. Box 87, Helwan, 11421, Cairo, Egypt.
authors: Amira M M
authors: AM
authors: Amin
authors: Refractory & Ceramic Materials Division (RCMD), Advanced Materials Department, Central Metallurgical R&D Institute (CMRDI), P.O. Box 87, Helwan, 11421, Cairo, Egypt.
authors: Yasser M Z
authors: YM
authors: Ahmed
authors: Chemical Engineering Department, Faculty of Engineering, El-Minia University, El-Minia, Egypt.
authors: Eman A
authors: EA
authors: Ashor
authors: Advanced Ceramics, University of Bremen, Am Biologischen Garten 2, 28359 Bremen, Germany.
authors: Ulrike
authors: U
authors: Hess
authors: Advanced Ceramics, University of Bremen, Am Biologischen Garten 2, 28359 Bremen, Germany.
authors: Kurosch
authors: K
authors: Rezwan
mesh_terms: D001672:Biocompatible Materials / Q000494:pharmacology; D002118:Calcium / Q000032:analysis*; D017610:Calcium Compounds / Q000494:pharmacology*; D002516:Ceramics / Q000494:pharmacology*; D006244:Hardness; D006801:Humans; D008277:Magnesium Oxide / Q000494:pharmacology*; D010316:Particle Size; D017640:Silicates / Q000494:pharmacology*; D012822:Silicon Dioxide / Q000032:analysis*; D013052:Spectrometry, X-Ray Emission; D014961:X-Ray Diffraction; D015040:Zirconium / Q000494:pharmacology*
chemical_list: D001672:Biocompatible Materials; D017610:Calcium Compounds; D017640:Silicates; D008277:Magnesium Oxide; D012822:Silicon Dioxide; D015040:Zirconium; C028541:zirconium oxide; C031293:calcium silicate; D002118:Calcium
keywords: Bioactivity; Calcia-silica; Fracture toughness; Magnesia; SBF; Vickers hardness; Zirconia