W.Q. Bai

In situ confocal microscopic observation on inhibiting the dendrite formation of a-CNx/Li electrode

To prevent the formation of dendritic lithium on the electrodes, nitrogen-doped amorphous carbon (a-CNx) films of nanosized thicknesses were deposited onto the surface of a metallic lithium foil by a magnetron sputtering technique. In this study, in situ visualization using confocal microscopy was adopted to monitor the formation of dendrite growth and a homogeneous nucleation theory was hypothesized for the first time. In addition, the voltage versus time test and the EIS analysis were used to characterize the stability of a-CNx coated Li electrodes. As a result, the nitrogen-doped amorphous carbon films can enhance the stability of the Li electrode and efficiently suppress the dendrite formation.

Mechanical Properties and in Vitro and in Vivo Biocompatibility of a-C/a-C:Ti Nanomultilayer Films on Ti6Al4V Alloy as Medical Implants

Hydrogen-free a-C/a-C:Ti nanomultilayer films are deposited on medical Ti6Al4V alloy using a closed field unbalanced magnetron sputtering under graded bias voltage. The mechanical and tribological properties of the nanomultilayer films are performed on the nanoindentor, Rockwell and scratch tests, and ball-on-disk tribometer. The biological properties are evaluated by cell cytotoxicity, genotoxicity, subchronic systemic toxicity and implant. The hard a-C/a-C:Ti nanomultilayer films on medical alloy exhibit high adhesion strength and excellent tribological properties in both ambient air and Hanks solution. Biocompatibility results reveal the film no cytotoxity, no genotoxicity, no subchronic systemic toxicity and no contraindications in implant systems. Because of excellent mechanical properties and biosafety, the carbon-based films on medical alloy unveils a prospective application in medical implants.