The proper interaction of bone tissue - the natural porous biomaterial - with a porous coated intra-osseous implant is conditioned, among others, by the implant porous coating poroaccessibility for bone tissue adaptive ingrowth. The poroaccessibility is the ability of implant porous coating outer layer to accommodate the ingrowing bone tissue filling in its pore space and effective new formed bone mineralizing in the pores to form a biomechanically functional bone-implant fixation. The functional features of the microtopography of intra-osseous implant porous surfaces together with the porosity of pore space of the outer layer of the porous coating are called by bioengineers the porostructural-osteoconductive properties of the porous coated implant. The properties are crucial for successful adaptive bone tissue ingrowth and further long-term (secondary) biomechanical stability of the boneimplant interface. The poroaccessibility of intra-osseous implants porous coating outer layers is characterized by - the introduced in our previous papers - set of stereometric parameters of poroaccessibility: the effective volumetric porosity fVef, the index of the porous coating space capacity VPM, the representative surface porosity fSrep, the representative pore size pSrep, the representative angle of the poroaccessibility Wrep and the bone-implant interface adhesive surface enlargement index y. Presented in this paper, an original method of evaluation of the porostructural-osteoconductive properties of intra-osseous implant porous coatings outer layer by means of the parameters of poroaccessibility was preliminary verified during experimental tests performed on the representative examples of porous coated femoral stems and acetabular cups of various hip endoprostheses. The computer-aided stereometric evaluation of the microstructure of implant porous coatings outer layer can be now realized by the authoring application software PoroAccess_1.0 elaborated in our research team in Java programming language
Metallic fuel slugs containing rare-earth (RE) elements have high reactivity with quartz (SiO2) molds, and a reaction layer with a considerable thickness is formed at the surface of metallic fuel slugs. The surface characterization of metallic fuel slugs is essential for safety while operating a fast reactor at elevated temperature. Hence, it is necessary to evaluate the surface characteristics of the fuel slugs so that chemical interaction between fuel slug and cladding can be minimized in the reactor. When the Si element causes a eutectic reaction with the cladding, it deteriorates the metallic fuel slugs. Thus, it is necessary to examine the characteristics of the surface reaction layer to prevent the reaction of the metallic fuel slugs. In this study, we investigated the metallurgical characteristics of the surface reaction layer of fabricated U-10wt.%Zr-Xwt.%RE (X = 0, 5, 10) fuel slugs using injection casting. The results showed that the thickness of the surface reaction layer increased as the RE content of the metallic fuel slugs increased. The surface reaction layer of the metallic fuel slug was mainly formed by RE, Zr and the Si, which diffused in the quartz mold.