To enhance the wear resistance of piston pin-hole surfaces and prolong piston service life, titanium (Ti)/titanium nitride (TiN)/diamond-like carbon (DLC) composite coatings were prepared on aluminium alloy substrates by multi-arc ion plating. The effects of the dinitrogen (N2):argon (Ar) flow ratio on the microstructure, adhesion strength, mechanical properties, and tribological behaviour of the coatings were investigated. The results show that, with increasing dinitrogen:argon flow ratio, the surface morphology became more uniform, the Micro-Vickers composite hardness of the coating/substrate system gradually increased, and the adhesion strength first decreased and then increased. When the dinitrogen:argon flow ratio was 4:1, the titanium/titanium nitride/DLC coating exhibited the best overall performance, with the lowest surface roughness of 0.18 μm, the lowest ID/IG value of 0.75, the highest adhesion strength of 53 N, and the highest composite hardness of 331 HV. In addition, the coating prepared at a dinitrogen:argon flow ratio of 4:1 showed the lowest coefficient of friction of 0.09, which was lower than those of the coatings prepared at dinitrogen:argon flow ratios of 1:4, 2:3, and 3:2. The dominant wear mechanism of the coatings is abrasive wear.
This work demonstrates that incorporating cerium oxide (CeO2) nanoparticles effectively tailors the surface and interfacial interactions within the cellulose acetate (CA) matrix, resulting in significant enhancements in the optical characteristics of the CA/CeO2 nanocomposite. The successful formation of the CA/CeO2 composites using the solution casting method was confirmed through scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FTIR). The FTIR identified the characteristic functional groups of CA and revealed strong interactions of CA and CeO2. EDX verified the effective incorporation of CeO2 in CA matrix, while TEM showed well-dispersed CeO2 with sizes 6 to 31 nm. The optical properties of CA and CA/CeO2 composite films were systematically investigated. The bandgap decreased from 4.22 eV for CA to 4.09, and 3.94 eV for composites containing CA/3.0%CeO2, and CA/4.5%CeO2, respectively. In contrast, the band tail increased from 1.11 eV for CA to 1.82, 2.70, and 2.85 eV respectively for CA/1.5%CeO2, CA/3.0%CeO2, and CA/4.5%CeO2. These results demonstrate that tailoring surface and interfacial interactions through CeO2 incorporation effectively modifies the optical behavior of CA, highlighting the potential of CA/CeO2 composite for optoelectronic applications.
This study introduces a novel, sustainable binary extract-based dyeing strategy for silk, utilizing natural colorants sourced from harmal (Peganum harmala) seeds and flowers of safflower (Carthamus tinctorius) petals. A central composite design was employed to systematically optimize essential dyeing parameters, fastness properties, and the use of mordant, and was done with the objective of maximizing color strength (K/S). After application of eco-friendly chemicals and bio-coating of silk, the dyed silk exhibited superior colorfastness properties, achieving ratings of 4–5 for washing, 4–5 for rubbing (dry and wet), and 5–6 for light fastness, confirming the durability of the coloration. The biological activities have shown good attributes of binary plant colorant for silk beneficial for the community. The use of central composite design in conjunction with microwave treatment has enabled the dyeing of silk at 70°C for 40 min with a binary extract at pH 5 obtained from 6 g of harmal and safflower binary powder. It is concluded that binary agrowaste can be used as a value-added natural dye for fabric using this modern approach and stable colorfast shades can be obtained using eco-friendly additives.
Membrane fouling and the permeability-selectivity trade-off remain central challenges in nanofiltration (NF) technology. Here, we report a one-step, aqueous-phase in situ surface modification strategy for polyamide (PA) NF membranes, in which the novel polyhydroxy zwitterionic compound 2-[bis(2-hydroxyethyl) (phenyl) amino] ethane-1-sulfonate (Z-PDEOA) is covalently grafted onto residual acyl chloride groups of the PA layer via esterification. Successful Z-PDEOA immobilization imparted the resulting PA-Z-PDEOA NF membrane with markedly improved surface hydrophilicity (water contact angle reduced to 6.7°) and a smoother, more homogeneous polyamide-polyester separation layer. The optimized PA-Z-PDEOA NF membrane had a water flux 3.4 times that of the original PA NF membrane. Meanwhile, the MgSO4 rejection rate increased to 97.58%, and the flux recovery rates for bovine serum albumin (BSA) and humic acid (HA) reached 99.81% and 93.25%, respectively. In the three dynamic BSA contamination tests, it was further demonstrated that the PA-Z-PDEOA NF membrane has excellent antifouling performance. These results establish Z-PDEOA grafting as an effective and scalable approach to designing high-performance antifouling NF membranes that simultaneously overcome the permeability-selectivity trade-off.
