A review on the recent advances concerning the fatigue performance of titanium alloys for orthopedic applications

This article presents a review on recent advances in the fatigue behavior of Ti alloys, especially the main commercial compositions for orthopedic applications. In the case of well‐known Ti–6Al–4V alloy, the major concern is related to the effect of the surface modification necessary to improve the osseointegration. The introduction of surface discontinuities due to the growth of a porous oxide layer, or the roughness development, may severely affect the fatigue performance depending on the level of alteration. In the case of additive manufactured Ti–6Al–4V, the fatigue response is also influenced by inherent defects of as‐built parts. Regarding the recently developed metastable β alloys, information about the fatigue properties is still scarce and mainly related to the effect of second phase precipitates, which are introduced to optimize the mechanical properties. The fatigue behavior of the Ti alloys is complex, as is their microstructure, and should not be neglected when the alloys are being developed or improved to be applied in medical devices.

Artificial synapses with a sponge-like double-layer porous oxide memristor

Closely following the rapid development of artificial intelligence, studies of the human brain and neurobiology are focusing on the biological mechanisms of neurons and synapses. Herein, a memory system employing a nanoporous double-layer structure for simulation of synaptic functions is described. The sponge-like double-layer porous (SLDLP) oxide stack of Pt/porous LiCoO2/porous SiO2/Si is designed as presynaptic and postsynaptic membranes. This bionic structure exhibits high ON–OFF ratios up to 108 during the stability test, and data can be maintained for 105 s despite a small read voltage of 0.5 V. Typical synaptic functions, such as nonlinear transmission characteristics, spike-timing-dependent plasticity, and learning-experience behaviors, are achieved simultaneously with this device. Based on the hydrodynamic transport mechanism of water molecules in porous sponges and the principle of water storage, the synaptic behavior of the device is discussed. The SLDLP oxide memristor is very promising due to its excellent synaptic performance and potential in neuromorphic computing.

Polyphenylene sulfide-coated wrench composites by nanopinning effect

When using a wrench, the nut is easily damaged due to improper operation or impact. Although coating a polymer layer on the surface of the wrench can effectively solve the above problem, the layer is easy to be deboned due to the lack of adhesion between the polymer and the surface of the wrench. Herein, we implemented an anodizing treatment strategy on the surface of the wrench to obtain a porous oxide film. Interestingly, during the anodization process, micro-nanopores with a specific diameter can be obtained by adjusting the voltage, temperature, and electrolyte concentration. Furthermore, the ammonium fluoride/ethylene glycol electrolyte was used to etch the formed large hole to form the large hole sleeve small hole structure. In order to inject polyphenylene sulfide (PPS) molecules into multiscale holes to form a pinning effect, we also used nano molding technology to inject PPS into the metal surface. The results showed that the adhesion between PPS and the wrench was greatly improved compared with the commonly used dip coating method.

Nanoporous Manganese Ferrite Films by Anodising of Electroplated Fe-Mn Alloys for Bifunctional Oxygen Electrodes

An electroplating–anodising method based on a facile and scalable electrochemical process was used to fabricate manganese ferrite porous oxide films for use as precious-metal-free oxygen reduction/evolution reaction (ORR/OER) electrodes. Porous...

NEW METHOD FOR DEPOSITION OF CERAMIC COATING ON AL ALLOY USING DUPLEX PROCESSES OF ANODIZING AND Al2O3 MODIFIED ELECTROLYTE MICRO -ARC OXIDATION (MAO)

In this work, surfaces of Al 6061 alloy were coated using anodizing and micro–arc oxidation ( MAO) duplex processes. MAO electrolyte was modified using ( 2-6 g/l )Al2O3 additives . X-ray diffraction (XRD), scanning electron microscopy (SEM), Vickers indenter, atomic force microscopy (AFM), and Microprocessor coating thickness meter ,were employed for characterization of the deposited coatings .Results showed that the coatings contained porous oxide ?-alumina with morphologies characterized by different levels of porosity non-uniform distribution, and their thickness and hardness increased by the increasing of Al2O3 additives. The research demonstrates that a relatively hard (421-490Hv), thick (43-65?m) and uniform coatings, can successfully be deposited on preanodized Al alloy (12-15 ?m with hardness of 190Hv) using Al2O3 additives containing MAO electrolytes as a new method for more future research on surface improvements of Al alloys