Metallic materials are among the most crucial engineering materials widely utilized as biomaterials owing to their significant thermal conductivity, mechanical characteristics, and biocompatibility. Although these metallic biomedical implants, such as stainless steel, gold, silver, dental amalgams, Co-Cr, and Ti alloys, are generally used for bone tissue regeneration and repairing bodily tissue, the need for innovative technologies is required owing to the sensitivity of medical applications and to avoid any potential harmful reactions, thereby improving the implant to bone integration and prohibiting infection lea by corrosion and excessive stress. Taking this into consideration, several research and developments in biomaterial surface modification are geared toward resolving these issues in bone-related medical therapies/implants offering a substantial influence on cell adherence, increasing the longevity of the implant and rejuvenation along with the expansion in cell and molecular biology expertise. The primary objective of this review is to reaffirm the significance of surface modification of biomedical implants by enlightening numerous significant physical surface modifications, including ultrasonic nanocrystal surface modification, thermal spraying, ion implantation, glow discharge plasma, electrophoretic deposition, and physical vapor deposition. Furthermore, we also focused on the characteristics of some commonly used biomedical alloys, such as stainless steel, Co-Cr, and Ti alloys.

An intelligent monitoring lubricant is essential for the development of smart machines because unexpected and fatal failures of critical dynamic components in the machines happen every day, threatening the life and health of humans. Inspired by the triboelectric nanogenerators (TENGs) work on water, we present a feasible way to prepare a self-powered triboelectric sensor for real-time monitoring of lubricating oils via the contact electrification process of oil–solid contact (O–S TENG). Typical intruding contaminants in pure base oils can be successfully monitored. The O–S TENG has very good sensitivity, which even can respectively detect at least 1 mg mL^–1 debris and 0.01 wt % water contaminants. Furthermore, the real-time monitoring of formulated engine lubricating oil in a real engine oil tank is achieved. Our results show that electron transfer is possible from an oil to solid surface during contact electrification. The electrical output characteristic depends on the screen effect from such as wear debris, deposited carbons, and age-induced organic molecules in oils. Previous work only qualitatively identified that the output ability of liquid can be improved by leaving less liquid adsorbed on the TENG surface, but the adsorption mass and adsorption speed of liquid and its consequences for the output performance were not studied. We quantitatively study the internal relationship between output ability and adsorbing behavior of lubricating oils by quartz crystal microbalance with dissipation (QCM-D) for liquid–solid contact interfaces. This study provides a real-time, online, self-powered strategy for intelligent diagnosis of lubricating oils.

In this study, anodization of an Al 6060 alloy has been investigated by in-situ electrochemical atomic force microscopy (EC-AFM) and electrochemical impedance spectroscopy (EIS) under operando conditions, to elucidate the role of intermetallic particles (IMPs) in the alloy. The Volta potential maps measured by scanning Kelvin probe force microscopy (SKPFM) reveal that the relative nobility is higher for AlFeSi type and lower for Mg₂Si type of particles as compared with the alloy matrix. The EIS results obtained at anodizing potentials show that the thickness of the barrier oxide layer increases linearly with the applied potential, but the oxide growth rate is lower than that of single crystal samples reported previously. Moreover, the EIS spectra show an inductive loop at low frequencies indicating an anodic dissolution process. The EC-AFM images display detailed morphological changes related to the IMPs during the anodization, which reveal certain localized dissolution in parallel to anodic Al oxide (AAO) formation on the alloy. The combined AFM and EIS measurements demonstrate that the IMPs in the alloy cause localized dissolution during anodization, resulting in a reduced AAO growth rate. The corrosion resistance of as-produced AAO film is low unless anodized at sufficiently high potential.