To increase the lifetime of metallic molds and protect their surface from wear, a fluorinated ethylene propylene (FEP) polymer was coated onto a stainless-steel (SS304) substrate, using an air spray process followed by a heat treatment. The microstructural properties of the coating were studied using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) as well as X-ray diffraction. The mechanical properties and adhesion behavior were analyzed via a nanoindentation test and progressive scratching. According to the results, the FEP coating had a smooth and dense microstructure. The mechanical properties of the coatings, i.e., the hardness and Young’s modulus, were 57 ± 2.35 and 1.56 ± 0.07 GPa, respectively. During scratching, successive delamination stages (initiation, expansion, and propagation) were noticed, and the measured critical loads L_C1 (3.36 N), L_C2 (6.2 N), and L_C3 (7.6 N) indicated a high adhesion of the FEP coating to SS304. The detailed wear behavior and related damage mechanisms of the FEP coating were investigated employing a multi-pass scratch test and SEM in various sliding conditions. It was found that the wear volume increased with an increase in applied load and sliding velocity. Moreover, the FEP coating revealed a low friction coefficient (around 0.13) and a low wear coefficient (3.1 × 10⁻⁴ mm³ N m⁻¹). The investigation of the damage mechanisms of the FEP coating showed a viscoelastic plastic deformation related to FEP ductility. Finally, the coating’s resistance to corrosion was examined using electrochemical measurements in a 3.5 wt% NaCl solution. The coating was found to provide satisfactory corrosion protection to the SS304 substrate, as no corrosion was observed after 60 days of immersion.

Conductive PLA is an innovative composite material that combines the ecological benefits of polylactic acid, a biodegradable thermoplastic, with electrical conductivity properties. Usually used in additive manufacturing for its ease of printing and low environmental impact, PLA remains an insulator, which limits its applications in the electrical field. To overcome this limitation, conductive fillers such as carbon nanotubes or carbon black are being added, opening the way to new functional uses. This study focuses on a specific composite: carbon black-filled PLA (PLA-CB). This material combines the qualities of traditional PLA with enhanced conductivity thanks to the carbon black particles. To assess its performance, a number of mechanical tests were carried out, including tensile tests on samples manufactured by 3D printing using the FFF process. The study focused in particular on the influence of crosshead speed and the impact of different notch shapes on the material's properties. To analyze the durability of PLA-CB, a probabilistic model based on the two-parameter Weibull distribution was used to assess the risk of failure under different conditions. Reliability curves were also established to better understand the tensile stress and strain at break of the material. This approach could also be applied to other 3D-printed polymers to refine their analytical and numerical modeling.

CrSiN coating was deposited by PVD magnetron sputtering on XC100 steel substrate. Microstructural and morphological properties were studied using SEM/EDS, XRD and AFM. Nanoindentation and scratching experiments were conducted to study the mechanical and adhesion behavior. Multi-pass scratch tests were conducted under different sliding conditions. Results showed that CrSiN coating has a dense and compact nanocomposite microstructure consisting of CrN nanocrystallites and SiN amorphous matrix. The CrSiN thin film exhibit, hardness and Young's modulus of 30.52 ± 1.85 GPa and 338.32 ± 13.5 GPa respectively. The H/E, H³/E² and 1/HE² ratios were also calculated (H/E ≈ 0.09, H³/E² ≈ 0.024 and 1/HE² ≈ 2.86 × 10⁻⁰⁷) and used to predict and assess the elastic/plastic and wear resistance. Critical loads LC1, LC2 and LC3 obtained with scratch test, were respectively 11.5 ± 0.12, 16.6 ± 0.23 and 20 ± 0.35N. Multi-pass scratch were analyzed and the friction coefficient (COF), the damage mechanism and wear volume were determined. The use of an energetic approach allowed to determine of the energetic wear coefficient. CrSiN coating revealed a low friction coefficient (around 0.1) and a low energetic wear coefficient (6.3 × 10⁻⁷ mm³/N.m). In addition, it was found that multi-pass scratch method has the potential to extract relevant information about wear behavior.

Natural composite materials are gaining interest due to their low cost, recyclability, and availability. This study examines hemp-polypropylene (HPP) composites, where polypropylene (PP) is reinforced with 30 wt.% short hemp fibers (HF). The composites were produced via melt compounding using a twin-screw extruder, followed by injection molding. To improve adhesion between hydrophilic hemp fibers and the non-polar PP matrix, polypropylene-graft-maleic anhydride (PP-g-MA) was used as a coupling agent. Structural and mechanical properties were assessed using SEM, FTIR, tensile, and scratch tests. Results revealed a significant improvement in fiber-matrix adhesion with the use of PP-g-MA, demonstrating enhanced interfacial bonding. The hemp fibers were uniformly dispersed within the PP matrix, resulting in a dense and homogeneous composite structure. Mechanically, the addition of 30 wt.% HF markedly increased the stiffness and tensile properties of the composites. The Young’s modulus and tensile strength of the HPP composites reached 3804 MPa and 28.07 MPa, respectively, compared to 1523 MPa and 22.98 MPa for neat PP. Scratch testing further supported these findings, showing a notable reduction in penetration depth upon the inclusion of hemp fibers. This study highlights the potential of hemp-reinforced polypropylene composites as a sustainable alternative in applications requiring enhanced mechanical performance.