Microstructural and Wear Behavior Characterization of Porous Layers Produced by Pulsed Laser Irradiation in Glass-Ceramics Substrates

In this work, wear behavior and microstructural characterization of porous layers produced in glass-ceramic substrates by pulsed laser irradiation in the nanosecond range are studied under unidirectional sliding conditions against AISI316 and corundum counterbodies. Depending on the optical configuration of the laser beam and on the working parameters, the local temperature and pressure applied over the interaction zone can generate a porous glass-ceramic layer. Material transference from the ball to the porous glass-ceramic layer was observed in the wear tests carried out against the AISI316 ball counterface whereas, in the case of the corundum ball, the wear volume loss was concentrated in the porous layer. Wear rate and friction coefficient presented higher values than expected for dense glass-ceramics

Influence of unit cell and geometry size on scaffolds electrochemical response

Additive manufacturing is a recent tool in medicine able to fabricate scaffolds to replace or regenerate bone tissues. The process permits the user to control scaffolds parameters such as size, unit cell, porosity, wall thickness, etc. However, the use of these three-dimensional geometries might negatively affect their corrosion behaviour. This paper studies the influence of Ti-6Al-4V ELI scaffold unit cell and, geometry size on the electrochemical response. Three different types of scaffold unit cell and three different geometry sizes were fabricated by additive manufacturing technique. The porosity of the scaffolds was studied by X-ray microtomography while surface changes, by scanning electron microscopy. Electrochemical behaviour was evaluated by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) in a phosphate buffered saline solution at 37 degrees C. Potentiodynamic polarization curves show that scaffolds showed a higher pitting susceptibility than solid samples at potentials higher than 1 V. EIS spectra show that the scaffolds geometry size promotes narrowing of the maximum phase angle at the high frequency range (10(2)-10(5)) due to a non-homogeneous distribution of current and potential853CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ141221/2015-1; 158744/2018-7National Council for Scientific and Technological Development (CNPq)National Council for Scientific and Technological Development (CNPq) [141221/2015-1, 158744/2018-7]; Spanish Ministry of Science, Innovation and Universities BaCTeria Project [MAT2017-86163-C2-R