Synthesis of Multilayered DLC Films with Wear Resistance and Antiseizure Properties

Diamond-like carbon (DLC) films have attracted considerable interest for application as protective films in diverse industrial parts. This is attributed to their desirable characteristics, such as high hardness, low coefficient of friction, gas-barrier properties, and corrosion resistance. Antiseizure properties, in addition to wear resistance, are required during the die molding of polymer and polymer-matrix composite parts. Graphite films can be easily peeled because the vertically stacked graphene sheets are bonded via weak van der Waals forces. The present study demonstrates the fabrication of multilayered DLC/Cu films, where the Cu film functions as a catalyst for the formation of a graphite-like layer between the DLC and Cu films. The DLC/Cu film was synthesized on a Si (100) substrate via plasma-enhanced chemical vapor deposition and magnetron sputtering. The peelability, wear resistance, microstructure, texture, and cross-section of the film were experimentally analyzed. The results indicated a variation in the peelability with the deposition conditions of the Cu film that comprised particles with diameters of several nanometers. The DLC film at the interface in contact with the Cu film was transformed into a graphite-like state i.e., graphitized. The surface of the multilayered film exhibited antiseizure properties with the peeling of the upper DLC film. The multilayered film also exhibited wear resistance owing to the repeated appearances of a new DLC film. It is expected that the wear-resistant films with antiseizure properties demonstrated in the present study will be utilized in various industrial sectors.

Nacre crystal growth as a paradigm of island growth mode: Hydrophobic substrate is one of the keys to the biomineralization

Nacre is a multilayered film material consisting of alternating layers of aragonitic tablets and organic membranes (OMs). However, at this time, no authors have discussed the growth mode of nacre from the perspective of the science of typical film materials. Here, for the first time, we focus on measuring the contact angles of the nacre growth surface (GS) using the contact angle meter. Additionally, we also investigate the GS's structure and phases using field emission scanning electron microscopy and X-ray diffractometer, respectively. We firstly found that: (1) The contact angles of the GS are always greater than 90°, with a maximum value of 113° and minimum value of 91°, indicating that the GS is hydrophobic. (2) The growth mode of GS is similar to the island growth mode (V-W) of the typical films. (3) The hydrophobicity of OMs plays an important role in the nucleation and growth of nacre. This research may provide new insights into the mechanism underlying nacre formation. In the field of thin-film, this conclusion will provide a new direction for the preparation and research of hydrophobic substrates, and a new idea for the development of thin-film technology.

Complex magnetic ordering in nanoporous [Co/Pd]5-IrMn multilayers with perpendicular magnetic anisotropy and its impact on magnetization reversal and magnetoresistance

Complex magnetic ordering in a porous [Co/Pd]5-IrMn multilayered film is modeled for interpreting its magnetization reversal and magnetoresistance mechanisms and explaining its high-resistive and low-resistive states in opposite external fields.