Two main drawbacks of electrophoretic produced coatings for surface treatment of metallic implants are low adhesion strength and poor sintering behavior resulting in high porosity and low cohesion strength of ceramic coatings. This work is focused on the effect of surface preparation methods of 316L stainless steel substrate on interface structure and chemical composition of ZrO 2 -SiO 2 on sintering capability and porosity network of coatings derived through electrophoretic technique. ZrO 2 -SiO 2 composite particles with different molar ratio of amorphous SiO 2 (0, 10, 20 and 30 mol.% SiO 2 ) were synthesized by sol gel procedure and then coated on the surface of modified 316L substrate followed by sintering at 1100 o C for 2 h. Before coating, substrate surfaces were prepared through three various methods including mechanical polishing, anodic oxidation, and electrochemical polishing. The results demonstrated that coating roughness were substantially influenced by substrate roughness in which the coating produced on anodic oxidized substrate showed the most roughness compared to the other coating samples. Focused ion beam tomography as an advanced technique was applied for studying the interface structure. An interlayer consisting of two parts including bottom porous layer and upper dense one was formed at the interface of coating applied on the 316L anodic oxidized substrate. This interlayer was created owing to the interaction and integration of ZrO 2 -SiO 2 particles with anodic oxide layer during sintering process. The formation mechanism of interlayer was discussed and a suitable model was proposed based on the information of tomography results. Corrosion studies showed that the best barrier performance with the lowest passivation current density of 0.95 nA.cm 2 was obtained for the coating applied on the anodic oxidized substrate which is related to the presence of compact interlayer at the interface. On the other hand, the impact of amorphous SiO 2 content in ZrO 2 -SiO 2 particles on the formation of interlayer, sintering ability of particles, and modifying of porous structure of coating was investigated. According to the obtained results, interlayer thickness was increased with increasing of SiO 2 content of coatings due to efficiently interaction of particles with anodic oxide layer. Moreover, diffusion of some elements from substrate such as Ni besides Cr and Mn was facilitated which was appeared as parallel bands across the interface. Porous network of coatings was reconstructed as 3D images using tomography technique and precise microstructural information including interconnected and isolated pores, volume fraction of pores, morphology, and pore volume histograms were thoroughly investigated. According to quantitative porosity analysis, total pore volume was decreased with increasing the SiO 2 content leading to formation of a densely packed structure. Total pore volume fraction was calculated around 11 Vol. % for ZrO 2 -30 mol.% SiO 2 which was approximately 2.4 times lower than that of pure ZrO 2 coating. In addition, volume fraction of connected pores was decreased and volume percent of isolated pores was increased as the SiO 2 content was increased in the coating structure, indicating an improvement of sintering behavior of particles. The dimension and distribution of isolated pores was similar for ZrO 2 -SiO 2 coatings with SiO 2 content lower that 30 mol.% SiO 2 ; however, they suddenly increased in ZrO 2 -30 mol.% SiO 2 coating sample. Equivalent diameter of connected pores for all coating samples was calculated in the micrometer range which make them suitable for bone growth propagation and reducing the stress shielding effect. Adhesion and cohesion strength of coatings were evaluated by miro-cantilever bending test. The results showed that the presence of interlayer has undeniable impact on increasing the adhesion strength. With increasing SiO 2 content the cohesion strength of coatings was also improved. To sum up. It can be concluded that varying the chemical composition of metallic substrate can be considered as the main factor in the formation of dense interlayer at the interface of ceramic coating resulting in substantially improvement in adhesion strength which can be achieved by electrochemical surface modification procedures. On the other hand, volume fraction of each component at ceramic composite coatings can refine the internal porous structure leading to an improvement in cohesion strength.