The article presents results of pitting corrosion studies of selected silicon cast irons. The range of studies included low, medium and high silicon cast iron. The amount of alloying addition (Si) in examined cast irons was between 5 to 25 %. Experimental melts of silicon cast irons [1-3] were conducted in Department of Foundry of Silesian University of Technology in Gliwice and pitting corrosion resistance tests were performed in Faculty of Biomedical Engineering in Department of Biomaterials and Medical Devices Engineering of Silesian University of Technology in Zabrze. In tests of corrosion resistance the potentiostat VoltaLab PGP201 was used. Results obtained in those research complement the knowledge about the corrosion resistance of iron alloys with carbon containing Si alloying addition above 17 % [4-6]. Obtained results were supplemented with metallographic examinations using scanning electron microscopy. The analysis of chemical composition for cast irons using Leco spectrometer was done and the content of alloying element (silicon) was also determined using the gravimetric method in the laboratory of the Institute of Welding in Gliwice. The compounds of microstructure were identify by X-ray diffraction.
Studies on biocompatibility of AISI 316LVM steel indicate the need to eliminate the nickel from the surface and replace it with other elements of improved biocompatibility. Therefore, in the presented work selected physicochemical and mechanical properties of the diffusive nitrocarburized layer formed by plasma potential by means of an active screen made of the Fe-Cr-Ni were studied. In the paper we present results of microstructure and phase composition of the layers, roughness, and surface wettability, potentiodynamic pitting corrosion resistance, penetration of ions into the solution as well as mechanical properties. The studies were conducted for the samples of both mechanically polished and nitrocarburized surfaces, after sterilization, and exposure to the Ringer’s solution. Deposition of the nitrocarburized layer increased the contact angle, surface roughness, surface hardness, and corrosion resistance with respect to the polished surfaces. The nitrocarburized layer is a barrier against the ions release into the solution and sterilization and exposure to Ringer solution. The obtained results showed beneficial increase of both mechanical and electrochemical properties of the deposited layer, and thus the applicability of the proposed method of surface treatment of the 316LVM steel for short-term implants after sterylization.