Mechanical properties of SiC ceramics by ultrasonic nondestructive technique and its bioactivity

Two SiC ceramics samples sintered at different firing temperatures, i.e. 1750, 1800 and 1900 degrees C were investigated through their mechanical properties using ultrasonic nondestructive technique. The velocity of longitudinal and shear ultrasonic waves were measured and used to calculate the longitudinal modulus (L), shear modulus (G), Young's modulus (E), bulk modulus (K) and Poisson's ratio (v). An attempt was done to use these materials as biomaterials. Simulated body fluids (SBF) containing inorganic concentrations close to human blood plasma was used to study the bioactivity of this material. The microstructure of SiC samples after immersion in SBF was investigated using scanning electron microscope (SEM). The results revealed that the longitudinal and shear ultrasonic velocities increase with increasing the sintering temperature in S1 and S2 and consequently increasing the mechanical properties. Generally, S I exhibited higher mechanical properties than S2 at 1900 degrees C. This is attributed to rigid framework, higher density and lower porosity. The obtained mechanical properties are favorable as compared with human cancellous bone and titanium for biomedical applications. It is then possible to conclude that SiC biomaterial implants appear as quite interesting alternative to Ti implants, by showing higher mechanical properties and lower density. Moreover, taking into account the biomechanical requirements (density, elastic modulus, strain to failure, etc.) of a particular type of bone in the body that should be repaired, bio SiC ceramics can be selected according the above properties. (c) 2007 Elsevier B.V. All rights reserved.