Thick Si-doped DLC coatings with high load bearing capacity on cold working tool steels by PECVD

For improving the wear resistance, thick silicon doped hydrogenated amorphous carbon (a-SiC:H) coatings were deposited on cold working tool steels by Plasma Enhanced Chemical Vapor Deposition (PECVD) technology. The increase of the acetylene (C2H2) flow rate distinctly tuned the microstructure of a-SiC:H coatings, including an increase in the coating thickness (>15 μm), a decrease in the silicon content, a greater sp2/sp3 ratio and higher degree of graphitization. The highest hardness of 19.61 GPa and the greatest critical load of 50.7 N were obtained. The coating showed low wear rates against different friction pairs and presented excellent abrasive wear resistance at high applied load and the wear rates decreased with increasing loads, which exhibited an outstanding application prospect in cold working tool steels.

Silicon-Doped Nanotube (Si-CNT) as Drug Delivery Nanocarrier for Osteoporosis Drug: Quantum Chemical Study

The aim of this study is to investigate the potential and capability of Si-CNT to detect and adsorb BMSF-BENZ ((4-bromo-7-methoxy-1-(2-methoxyethyl)-5-{[3-(methylsulfonyl)phenyl]methyl}-2-[4-(propane-2-))yl) phenyl]-1H-1,3-benzothiazole) molecular. For this purpose, we considered different configurations for adsorbing BMSF-BENZ drug on the surface of the Si-CNT nanocluster. All considered configurations are optimized using DFT theory at the 6-31G** basis set and B3LYP level of theory, and then from optimized structures, for each nanoparticle, we selected four stable models for the adsorption of BMSF-BENZ from (Br, N8, N9, N58, O35, O41 and S) active sites on the surface the selected nanoparticle. and Quantum theory of atoms in Molecular Analysis (QTAIM), and Molecular Orbital Analysis (MO) was also established. The calculated results indicate that the distance between nanocluster and drug from the N8 site is lower than from all other locations sites for all investigated nanoparticles, and adsorption of BMSF-BENZ from the N8 site is more favorable especially for the Si-CNT nanotube. The adsorption energy, hardness, softness, and fermi energy results reveal that the interaction of BMSF-BENZ with Si-CNT, is an encouraging adsorbent for this drug as Eads of BMSF-BENZ/Si-CNT complexes are (-5.15, -24.21, -8.22, -17.03, -13.16, -2.22, -12.70) kcal/mol in the gas phase. As well, the appropriate and spontaneous interaction between the BMSF-BENZ drug and Si-CNT nanoparticle was confirmed by investigating the quantum chemical molecular descriptors and solvation Gibbs free energies of all atoms. Si-CNT can be used as an amperometric sensor to detect the BMSF-BENZ drug molecule. Thus, we propose that the Si-CNT can be a promising candidate as a drug delivery vehicle for BMSF-BENZ drug molecules.