In order to improve the performance of 17-4PH under wear conditions (e.g., gears, etc.) and reduce the cost of metal additive manufacturing, TiC needs to be added to 17-4PH to improve its wear resistance. Micron-sized TiC-reinforced 17-4PH stainless steel composites with different contents (0–15 wt%) have been prepared by fused filament fabrication 3D printing for the first time. The effects of TiC content on the structure and properties of composites were studied by XRD, SEM, and sliding wear. The obtained results show that the microstructure of TiC-reinforced 17-4PH stainless steel composites mainly consists of austenite. With the increase in TiC content, the grain size is obviously refined, and the average grain size decreases from 65.58 μm to 19.41 μm. The relative densities of the composites are maintained above 95% with the addition of TiC. The interfaces between TiC particles and the 17-4PH matrix are metallurgical bonds. The hardness of the composites increases and then decreases with increasing TiC content, and the maximum hardness (434 HV) is obtained after adding 10 wt.% of TiC content. The wear rate of the composites was reduced from 2.191 × 10⁻⁵ mm³ /(N‧m) to 0.509 × 10⁻⁵ mm³ /(N‧m), which is a 3.3-fold increase in wear resistance. The COF value declines with the addition of TiC. The reasons for the significant improvement in the composites’ performance are fine grain strengthening, solid solution strengthening, and second phase strengthening. The wear mechanisms are mainly abrasive and adhesive wear. Compared to the 10 wt% TiC composites, the 15 wt% TiC composites show limited improvement in wear resistance due to more microcracks and TiC agglomeration.

The application of superamphiphobic coatings improves the surface’s ability to repel fluids, thereby greatly enhancing its various functions, including anti-fouling, anti-corrosion, anti-icing, anti-bacterial, and self-cleaning properties. This maximizes the material’s potential for industrial applications. This work utilized the agglomeration phenomenon exhibited by nano-spherical titanium dioxide (TiO₂) particles to fabricate 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) modified TiO₂ (TiO₂@fluoroPOS) fillers with low surface energy. This was achieved through the in-situ formation of protective armor on the surface of the agglomerates using the sol-gel method and fluorination modification. Polyvinylidene fluoride-tetrafluoropropylene (PVDF-HFP) and TiO₂@fluoroPOS fillers were combined using a spraying technique to prepare P/TiO₂@fluoroPOS coatings with superamphiphobicity. Relying on the abundance of papillae, micropores, and other tiny spaces on the surface, the coating can capture a stable air film and reject a variety of liquids. When the coatings were immersed in solutions of 2 mol/L HCl, NaCl, and NaOH for a duration of 12 h, they retained their exceptional superamphiphobic properties. Owing to the combined influence of the armor structure and the organic binder, the coating exhibited good liquid repellency during water jetting and sandpaper abrasion tests. Furthermore, the coating has shown exceptional efficacy in terms of its ability to be anti-icing, anti-waxing, and self-cleaning.

To increase the residual stress stability of Au films while reducing the residual stress level, the effect of deposition temperature on long-term residual stress evolution of Au films under different conditions were studied. Au films with a thickness of 360 nm were deposited using e-beam evaporation on fused silica under different temperatures. Observations and comparisons were made of the microstructures of Au films deposited under different temperatures. Results showed that by increasing the deposition temperature, a more compact microstructure of Au film was obtained, which was manifested in increased grain size and reduced grain-boundary voids. After deposition, a combined process consisting of natural placement and 80 °C thermal holding was conducted on the Au films, and the residual stresses were monitored using the curvature-based technique. Results showed that the initial tensile residual stress of the as-deposited film decreased with the deposition temperature. The Au films with higher deposition temperatures showed better residual stress stability, maintaining low stress levels in the subsequent long-term combination of natural placement and thermal holding. The mechanism was discussed based on the differences in microstructure. Comparisons were made between post-deposition annealing and increased deposition temperature.

Coal dust particles adhering to a camera lens reduce its light transmittance, which deteriorates the performance of the camera and may lead to serious problems with mining equipment that requires visual ability. Aiming at improving coal dust removal and cleaning technologies, the adhesion behavior of coal dust with fused silica is studied here. Experiments were conducted from microscopic and statistical points of view. The adhesion force between a single coal dust particle and fused silica is tested using atomic force microscopy (AFM), and the number and size distribution of large amounts of coal dust particles on fused silica are tested using a home-made adhesion experimental platform and image processing method. The results show that the adhesion force increases at high relative humidity (RH); it is dominated by van der Waals forces at low RH and capillary forces at high RH. The fused silica glass surface is predominantly covered by small-sized coal dust particles, and the total number of particles as well as the proportion of large-sized particles increases with RH. The theoretical values of van der Waals and capillary forces are significantly larger than the experimental values, owing to the irregular shape and roughness of the surface of the coal dust.

This study aimed to acquire a comprehensive explanation on how the residual stress in the surface layer affects the contact behavior of solids. Plastic yield inception of residual stressed surface layer/substrate system during contact is simulated using the finite element method with the software ANSYS Workbench. The critical loads and locations for yield inception were acquired for contact systems with different residual stress levels and different surface layer thicknesses. Results show that the residual stress in the surface layer has little influence on the stress field in the substrate during contact. The influence of the residual stress on the critical yield load is mainly due to variations in the stress field in surface layer. A moderate compressive residual stress is preferable for increasing the critical yield load. An optimal value of compressive residual stress of 60% of the yield strength of surface layer was found to increase the critical yield load. The surface layer thickness and residual stress determine the yield inception location and the critical load of the contact system jointly.