Snake skins evolved to withstand permanent friction and wear during sliding. Here, the microstructure of ventral scales of the snake Lampropeltis getula californiae was analyzed using scanning electron microscopy, and the long-term dynamic friction behavior was investigated by reciprocating sliding friction tests. A smooth epoxy resin with similar elasticity modulus and hardness was used for…
Two multilayer solar selective absorber coatings [Al/CrN0.95/Cr0.96Al0.04N1.08/Cr0.53Al0.47N1.12/Al2O3 (stack #1) and Cr0.96Al0.04N0.89/Cr0.62Al0.38N1.00/Cr0.53Al0.47N1.12/Al2O3 (stack #2)] were deposited on 316L steel by combining direct current (DC) and high power impulse magnetron sputtering (HiPIMS) technologies with the aim of increasing the working limit temperature. The composition and thickness of the constituent layers were optimized using CODE software to achieve…
This work presents a complete study of the influence of HiPIMS pulse characteristics on the microstructure, chemical composition, mechanical and oxidation resistance properties of CrN thin films. The investigated parameters were frequency and pulse length at two different nitrogen fluxes, maintaining constant the duty cycle conditions (2%). The effect of a negative bias of 100…
Nanostructured NbC thin films with variable contents of Nb and C were prepared by direct current (DC) magnetron sputtering, and for the first time, via high power impulse magnetron sputtering (HiPIMS) searching for an improvement in the tribological properties. X-ray diffraction shows that increasing the carbon incorporation, the crystalline composition evolves from Nb2C to NbC…
El cambio climático ocasionado por las emisiones de gases con efecto invernadero y el agotamiento de los combustibles fósiles a corto-medio plazo hacen necesaria la búsqueda de nuevas fuentes de energía alternativas, limpias y renovables. De entre ellas, la energía solar es una de las mejores opciones por su gran disponibilidad para la generación de…
El titanio comercialmente puro (Ti c.p.) y la aleación Ti6Al4V, son los biomateriales metálicos con el mejor pronóstico para la reparación clínica del tejido óseo. Sin embargo, a pesar de sus ventajas, 5-10% de los implantes fallan durante los cinco años post-implantación. Éstos se asocian fundamentalmente al apantallamiento de tensiones (diferencias de rigidez entre el…
Las celdas solares (CSs) de tercera generación son dispositivos nanotecnológicos que convierten directamente la luz solar en electricidad y suponen el paradigma de la investigación en energías renovables de cuyo aprovechamiento dependerá el futuro energético del planeta. Recientemente, un ejemplo particular de CSs que contienen una perovskita de haluro organometálico como absorbedor de luz han…
La mejora de los materiales empleados en los dispositivos usados en el campo de las energías renovables permitirá incrementar la eficiencia de los mismos haciéndolos más competitivos y rentables. El presente proyecto pretende desarrollar nuevos recubrimientos absorbedores selectivos de la energía solar aptos para trabajar a temperaturas superiores a las posibles con los materiales actualmente…
Cr-doped diamond-like carbon (Cr-DLC) films with Cr contents ranging from 3 up to 20 at. % were synthesised in a codeposition process with HiPIMS (Cr deposition) and DC-pulsed technology (C deposition). The application of HiPIMS at low frequencies was observed to significantly enhance the energy density during the Cr plasma discharge due to the interaction…
a-C:Ag coatings (1.2-23.4 at.% of Ag) were deposited using magnetron sputtering. Ag nanoparticles appear embedded in the carbon matrix or segregated to the column boundaries or surface. The silver doping has not promoted significant changes of the sp(2)/sp(3) ratio although a decrease of the hardness is observed (from 17 to 7 GPa). The tribological behavior…