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As China continues to advance the modernization process, a large number of infrastructure construction projects need to use shield machines to build tunnels. As a key component of the shield machine/TBM direct contact working environment, the hob is extremely complex and extremely harsh due to the extremely complex and extremely harsh working environment, resulting in hobs. It is very easy to damage when in service. The damage of the hob directly leads to many problems such as project delay and capital consumption. Therefore, improving the mechanical properties of the hob and prolonging the service life is an important engineering problem to be solved urgently. Based on the service performance of disc cutter, this paper analyzes its failure form and wear mechanism, and summarizes the strengthening process and improvement method of the H13 steel disc cutter ring. In this paper, the advantages and disadvantages of previous researchers and optimization methods are reviewed for H13 steel material composition, heat treatment process, surface coating strengthening process, and other processes. Finally, the performance strengthening of hob cutter ring is discussed and prospected, in order to provide a reference for hob strengthening technology path and industrialization realization.

Aluminum (Al) nanoparticle (ANP), as a metal fuel agent, has excellent combustion rate and energy density. However, several critical research gaps of ANP still exist. This study is focused on the annealing properties of ANP and its coating performances under the mixture of ethanol and ether molecules. According to those obtained molecular dynamic (MD) simulation results, the microstructure of ANP in the annealing process and the formation of ethanol–ether binary coating are discussed in this paper. During the melting process, the melting point of ANP could be analyzed by the inflection point of its atomic potential energy and the mean square displacement, then the accuracy of EAM force field could be verified. Because surface atoms have lower potential energy than inner atoms, it seems that the melting of ANP started from the particle surface and diffuses from surface to the core. When the melted Al cluster is solidified until 300 K, the microstructure of the crystallized particle is largely affected by the cooling rate. If the cooling rate if too fast, it is not enough for the Al cluster to recrystallize, which is called as the “freezing effect” for ANP. Next, the binary “competitive adsorption” behavior of ethanol and ether on the surface of ANP was simulated according to different ethanol–ether molecular ratios. Analyses of ethanol–ether binary coating layer show that the main component of binary coating is ethanol, but not ether. This competitive superiority of ethanol is caused by its own adsorption mechanism and molecular migration in this mixture of ethanol and ether.

In this study, Inconel 625 (IN625) alloy and tungsten carbide (WC) with additive ratios of 10%, 30% and 50% by weight were coated on the magnesium alloy surface. The coating process was carried out with the High Speed Oxy-Fuel Spray (HVOF) technique. Microstructure characterizations were performed by profilometry, optical microscope (OM), scanning electron microscope (SEM), energy distribution X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analysis. Microhardness measurements and wear tests were also used to determine mechanical properties. Dry sliding wear tests were carried out at loads of 2, 6 and 10 N and at a sliding distance of 150 m. It has been observed that powder mixtures with different additive ratios form different microstructures. It was observed that the Surface Centric Cubic Structure (FCC) $\gamma$ (gamma) matrix and WC carbide as well as W₂C, W₆C${}_{2.54}$, M₆C and M${}_{23}$C₆ carbides were formed on the obtained coating layers. Depending on the increase in WC additive ratio, the surface roughness values increased. The microhardness values in the coating layers varied between 392 and 508 HV${}_{0.1}$WC additive to Inconel 625 improved its hardness and wear resistance. While 0.64, 0.97 and 1.19 mg weight loss was measured for 2, 6 and 10 N in the pure AZ91 sample, these values were 0.12, 0.2 and 0.31 mg in the IN625WC-50 sample measured. The coating with the highest hardness and wear resistance was obtained with a high WC ratio.

A nanopore array with diameter of ~30 nm was fabricated by use of focused ion beam (FIB) scanning and thin film coating on Si(100). A thin film of SiO₂ with thickness of 200 nm (used as a sacrificial layer) was coated by physical evaporation deposition (PVD) first. Next, the thin films of poly-silicon with thickness of 50 nm were coated on double side of the substrate. A window with an area of 2 × 2 mm² was opened by reactive ion etching from bottom side and reached to the thin film of SiO₂. After that, a fine controlled FIB milling with bitmap function (milling according to a designed pattern in a defined area) was used to scan the area. Signal is obtained by a sensor inside the vacuum chamber collecting secondary electrons emitted from the sputtered material when the beam reach the layer of SiO₂. Stopping the milling process at this moment, the nanopore array was derived after removing the sacrificial layer by wet chemical etching. The nanopore arrays were characterized using transmission electron microscopy (TEM) after the FIB drilling.

Accurately predicting the failure of multilayered surface systems, including coatings on tools or products, is of significance for all of the parties concerned within the chain of design, manufacturing and use of a product. Previous modeling work has, however, been focused largely on the effect of individual parameters rather than on the performance of a multilayered system as a whole. Design and manufacture of multilayered surface systems, currently, still relies largely on experiments and failure tests. A parameterized approach which considers geometrical, material, interfacial and loading variables, processing history, thermal effects, surface-failure modeling, etc. has therefore been developed to address the situation in order to be able to improve the efficiency and accuracy of the analysis and design of multilayered coating-systems. Material property values for the hardened case of the substrate are described with a function of the hardened depth and defined with a field method. Initial residual stresses calculated using a newly developed theoretical model are incorporated into the model as initial stress conditions. Thermo-mechanical coupled modeling is incorporated into the model so as to be able to consider temperature effects. These are associated with a cohesive-element modeling approach, which has been used to predict indentation-induced crack initiation and propagation within the coating layer. The comparison of experimental results with those of numerical modeling affords excellent agreement.

The parameterized modeling method developed allows for the parameters to be changed easily during a series analysis. Combined with the capability of the prediction of cracking of the coatings, the developed method/model provides an efficient way for investigating the effects of these parameters on the behavior of multilayered systems, which is demonstrated by the analysis of three cases of the coated tool steels (H11): (i) a substrate without being pre-heat-treated; and (ii) two substrates with a shallow and a deep hardened-case, respectively, (both are treated by plasma-nitriding). The results showed that the case-hardening of a substrate has a significant influence on the performance of the surface system with coating, especially on its load-bearing capacity and the cracking of the coating.

On cutting tools for high performance cutting (HPC) processes or for hard-to-cut materials, there is an increased importance in so-called superlattice coatings with hundreds of layers each of which is only a few nanometers in thickness. Homogeneity or average material properties based on the properties of single layers are not valid in these dimensions any more. Consequently, continuum mechanical material models cannot be used for modeling the behavior of nanolayers. Therefore, the interaction potentials between the single atoms should be considered. A new, so-called atomic finite element method (AFEM) is presented. In the AFEM the interatomic bonds are modeled as nonlinear spring elements. The AFEM is the connection between the molecular dynamics (MD) method and the crystal plasticity FEM (CPFEM). The MD simulates the atomic deposition process. The CPFEM considers the behavior of anisotropic crystals using the continuum mechanical FEM. On one side, the atomic structure data simulated by MD defines the interface to AFEM. On the other side, the boundary conditions (displacements and tractions) of the AFEM model are interpolated from the CPFEM simulations. In AFEM, the lattice deformation, the crack and dislocation behavior can be simulated and calculated at the nanometer scale.

A set of continuum viscoplastic damage constitutive equations is presented in this paper. The equations are calibrated for a TiN coating material, and a number of substrate materials, and are implemented into the commercial finite element (FE) solver, ABAQUS, through the user-defined material subroutine, VUMAT, for FE simulation. An FE model has been created to simulate a load-bearing test. Studies are carried out to investigate failure features of the coating with variations in coating thickness for three different substrate materials: pure copper, a gear steel and a tool steel. It has been demonstrated that the proposed damage equations can be used to predict failure features of coatings, which are affected by the thickness of the coating and the stiffness of the substrate.

Local residual stress fields often influence and even govern some of the mechanical properties of multilayered coatings at nanoscale. An approach is developed for the evaluation of the local residual stress with the representative volume element (RVE) of a multilayered coating and the concept of lattice mismatch between neighboring layers, incorporating high-precision density functional theory calculations. The calculated results are in good agreement with experimental reports, even if each individual host constituent is assumed linearly elastic, demonstrating the validity of the proposed approach in the evaluation of the residual stress. In addition, it is found that lattice mismatch is a reasonable key factor to account for the extremely large residual stress in multilayered transitional metal-nitride coatings.

Surface coatings such as hydrophobic and transparent coatings were applied to cement concrete surfaces using Polydimethylsiloxane (PDMS) coatings, which have nanometer-sized particles. The degree of contact between the liquid and the coated surface reveals the surface’s ability to repel water, commonly referred to as hydrophobicity. By depositing silicon coating on the surface, we successfully achieved superhydrophobicity on cement concrete, providing excellent resistance against water damage. We are striving to replicate the natural superhydrophobic properties found in nature to create artificial surfaces with similar characteristics. In this study, we experimented to develop and evaluate superhydrophobic coatings on cement concrete. The application of PDMS on the cement concrete yielded fascinating results, with the typical contact angle of the coated layer measuring 178 degrees. We utilized ImageJ software to analyze the results. This innovative approach holds great promise for enhancing water repellency in the field of construction.

Surface coating of LiNi${}_{0.5}$Mn${}_{0.3}$Co${}_{0.2}$O₂ (NMC532) is an effective approach to improve the capacity retention and energy density through increasing cutoff operation voltage. In this work, NMC532 electrodes are directly coated with Ta₂O₅ via atomic layer deposition (ALD). The 5 cycles ALD-Ta₂O₅-coated electrodes have the significantly enhanced capacity cyclability. The high-quality amorphous ALD-Ta₂O₅ layer retards the interfacial reaction between NMC532 and electrolyte, and prevents the dissolution of the active materials, improving the phase stability of the NMC532 materials.

Inactivation of pathogens from environment and inhibition of biofilm formation on various surfaces are important for biosafety, biosecurity and public health. Carbon nanotubes (CNTs) possess antimicrobial effects in addition to their unique optical, electrical, mechanical and thermal properties. This review summarizes the antimicrobial effects of single walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) in suspensions and on CNT contained surfaces. To increase antimicrobial effects, CNT composites containing other antimicrobial reagents are introduced. Also described are the possible antimicrobial mechanisms of CNTs.

The method of chemical plating was used to synthesize metal (Ni, Co or Cu) coated LiMn₂O₄ materials. The matrix material LiMn₂O₄ spinels were synthesized by microwave method. The structure and the electrochemical properties of the samples during cycles were characterized. XRD data shows that such kind of treatment has little effect on the phase purity and lattice constant in contrast with uncoated LiMn₂O₄ spinel. The electrochemistry analysis shows that the initial discharge capacity of all coated LiMn₂O₄ spinels is rather small comparing with that of uncoated LiMn₂O₄, while after long cycles they indicated very good capacity retention.

The effects of sonication during electrolysis include the cavitation phenomena. The collapse of a bubble near the surface of substrate causes the formation of high-speed liquid jet towards the surface of substrate, which travels along its surface. The liquid jet speed is 120 m/s, the water hammer pressures is 200 MPa and shock wave pressure is 1000 MPa. In this work the crystal orientation and hardness of zinc electrodeposited films were determined by frequency of ultrasonic irradiation, flow rate and hydrostatic pressure. The texture coefficient of {002} plane increased, and {100} and {102} planes decreased with sonication and increasing of acoustic intensity. These effects maximized at 45 kHz and 0.35 W/cm². The texture coefficient of {002} plane increased, and {100} plane decreased with increasing of hydrostatic pressure. The crystal orientations were not affected with liquid flow. The hardness of deposited films increased with increasing of acoustic intensity and maximized at 45 kHz and 0.35 W/cm². The hardness decreased with increasing of hydrostatic pressure. It was concluded that the effects of sonication on the hardness were shock wave pressures.