CHARACTERIZATION OF GRIT BLASTED METALLIC BIOMATERIALS BY THERMOELECTRIC POWER MEASUREMENTS H. Carreon 1 , S. Barriuso 2 , J. L. González-Carrasco 2,3 , F. G. Caballero 2 , M. Lieblich 2 1 Instituto de Investigaciones Metalúrgicas; Edif.”U” C.U., 58000-888, Morelia, México 2 Centro Nacional de Investigaciones Metalúrgicas; Avda.Gregorio del Amo 8, E28040, Madrid, España 3 Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, España Keywords: Grit Blasting; Thermoelectric Measurements; Residual Stresses; Biomaterials Abstract The grit blasting is a low-cost technique successfully used to enhance mechanical fixation of the implants through increasing their roughness. As a result of the severe plastic surface deformation, it produces subsurface effects such as grain refinement, hardening and compressive residual stresses which are generally evaluated with destructive techniques. In this research work, non-contacting and contacting thermoelectric power measurements are performed in blasted 316LVM and Ti-6Al-4V specimens using Al2O3 and ZrO2 particles which yield a coarse and a fine rough surface, respectively. This study correlates the microstructural changes induced by the grit blasting treatment and the limitations and advantages of each of the nondestructive thermoelectric techniques based on the Seebeck effect used to evaluate these biomaterials. Introduction It is well known that surface properties play an important role in metallic materials used in bio-medical applications. Since the biological response is correlated directly with surface properties it is comprehensible the intense activity in superficial modification by physics or chemistry methods in this field. Grit blasting, one of the most popular surface modification of metallic biomaterials, enhances the mechanical fixation of the implant through the increase in roughness [1-3]. Roughening is developed by bombarding the surface with a high- velocity jet of ceramic particles, being the final roughness a function of the processing parameters (pressure, distance, time,…) and blasting particles (nature, shape, size). As the plastically deformed surface layer tries to expand relatively to the intact interior of the specimen, residual compressive stress gradients develops perpendicular to the surface at shallow depths with a maximum value at a depth in the range of 5 to 60 μm. This surface treatment also may cause subtle variations in the subsurface material properties, such as increased hardness and grain size refinement, which are consequences of the significant plastic deformation through cold work. Blasted affected zones may extend to a depth of up to about 200 μm. The subsurface hardening and the near-surface compressive stress gradient play a beneficial role by retarding fatigue crack nucleation and further Characterization of Minerals, Metals, and Materials Edited by: Jiann-Yang Hwang, Sergio Neves Monteiro, Chengguang Bai, John Carpenter, Mingdong Cai, Donato Firrao, and Buoung-Gon Kim TMS (The Minerals, Metals & Materials Society), 2012 443