The demand for advanced coating materials in high-temperature and wear-resistant applications has led to the exploration of multicomponent systems that offer superior mechanical properties. Among these, AlCrSiN has emerged as a promising candidate owing to its ability to blend the thermal stability and hardness of AlCrN aided by grain refinement along with the presence of amorphous phase as a result of silicon addition. In this study, SS 304 substrates were used to deposit AlCrSiN thin films through magnetron sputtering process. This work focuses on the structural, hardness, scratch, wear and adhesion properties of AlCrSiN thin films as a function of substrate temperature. The AlCrSiN coating deposited at 400°C exhibited a hardness of 23 GPa and an (H/E) ratio of 0.08, which is an apparent measure of good wear-resistance coating. The work of adhesion significantly increased from 18 to 150 Jm −2 as the substrate temperature was gradually boosted from 30 to 500°C. Coatings facricated at room temperature and 300°C displayed an amorphous structure, while those deposited at 400°C and 500°C developed CrN/AlN crystallites averaging 16 nm in size within the amorphous matrix. Furthermore, the coefficient of friction (COF) was maintained between 0.27 and 0.30. These findings underscore the potential of AlCrSiN coatings to enhance the wear resistance and mechanical performance of substrates in demanding industrial applications, with substrate temperature playing a key role in optimizing coating properties.

Laser metal deposition or laser cladding, is increasingly utilized for creating coatings and bulk structures in engineering components. While the occurrence of tensile residual stress and crack formation in coatings has been extensively studied with continuous wave lasers, there is limited research on pulsed wave lasers despite their potential to mitigate these issues. This study explores the use of substrate preheating through an induction coil to examine the possibility of reducing cracks in a pulsed wave laser-deposited NiCoCrAlY coating, a material commonly applied in high-temperature environments like gas turbines and traditionally deposited through thermal spray methods. The microstructures were characterized using electron microscopy with an integrated element analyzer. Residual stress and phase formation were investigated using Xray diffraction. The dye penetration test was employed to detect surface cracks. The coating exhibited significant transverse cracking at room temperature, which was progressively eliminated by increasing the substrate temperature to 700 °C. This temperature increase led to a substantial reduction in residual stress. The as-deposited coating at room temperature consists of a β-dominated dual-phase microstructure, which is almost retained in the crack-free condition despite compromising on the grain growth and the γ-Ni content to some extent. The crack-free coating achieved a 2.7-fold increase in scratch hardness compared to the substrate. This experimental study on pulsed wave laser deposition provides an effective approach for eliminating cracks in NiCoCrAlY coatings, offering insights into how pulsed wave laser deposition can produce durable, crack-free coatings for brittle alloys in high-performance applications.

The Ti6Al4V alloy was first subjected to annealing treatments at different temperatures to obtain various microstructures, followed by micro-arc oxidation (MAO) treatment. This study investigated the influence of annealing treatment on the microstructure and wear behaviour of MAO coatings. The results indicate that annealing treatment affects the microstructure of MAO coatings, potentially due to variations in electrical conductivity of the substrate. A higher electrical conductivity enhances the growth of MAO coatings, leading to an increase in their thickness and a higher rutile TiO 2 content. The primary wear mechanism of MAO coatings is adhesive wear. Meanwhile, high hardness and low porosity collectively enhance their wear resistance. Notably, the MAO coatings prepared on the alloy annealed at 860 °C exhibit low roughness, low porosity, high hardness, and the lowest wear rate of 79.65 μm³·N − ¹·m − ¹.

This study investigates the surface integrity of coated low-carbon steel in simulated marine splash zones, addressing the need for standard surface roughness guidelines to improve coating adhesion. Using laboratory test equipment (designed and developed as per ISO 11130), bare and coated S275JR grade carbon steel specimens are subjected to cyclic wet-dry conditions for 90 days in 3.5% NaCl solution, with corrosion rates assessed via analysis of mass-loss taken at five intervals. The surface roughness is varied by sandblasting, with three different grit abrasives, to produce fine, medium and coarse blasted profiles (ISO 8501-1), followed by spray painting to a Nominal Dry Film Thickness (NDFT) of 450 µm (ISO 12944-9). Coated specimens are scribed as per ASTM D1654 and rust creepage due to loss of adhesion around the scribe line is measured. Results for uncoated specimens show an accelerating corrosion trend, following a power law with an exponent of 1.24. FTIR analysis reveals rust phases such as lepidocrocite (γ-FeOOH), goethite (α-FeOOH), akaganeite (β-FeOOH) and magnetite (Fe 3 O 4 ). Control (non-blasted) coated specimens ( Ra : 1–2 µm and Rz DIN : 5–10 µm) exhibit severe cathodic delamination followed by a peeling and flaking effect. In contrast, medium-blasted coated specimens ( Ra : 10–13 µm and Rz DIN : 50–65 µm) show improved adhesion due to enhanced mechanical interlocking bonds at the coating-substrate interface.

The High Velocity Oxygen-Fuel (HVOF) process has recently increased interest in tungsten carbide (WC) coatings for enhancing surface properties of lightweight alloys such as Al6061, widely used in aerospace, automotive, and industrial applications. In this research work, an investigation into the microstructural characteristics, hardness improvements, Coefficient of friction (COF), and reductions in wear rate of the WC coatings applied at a thickness of 100 microns and 200 microns on Al6061 alloy is discussed. Scanning electron micrographs show a dense and uniform WC layer with minimal porosity. EDAX confirmed the presence of WC and supporting elements. In the case of the 100-micron coating, there was an increase of 337.5% over the base alloy, and in the case of the 200-micron coating, the improvement was 525%. The COF was reduced by 22.5% and 30.9%, and the wear rate decreased by 25% and 41.6% for the respective coating thicknesses.

This study explores the interplay between particle size disparity and energy polydispersity in shaping the surface morphology of a two-dimensional binary Lennard-Jones (LJ) mixture. Through molecular dynamics (MD) simulations, we analyze how variations in size-ratio (α) influence structural ordering in the solid phase, characterized by the radial distribution function (RDF) and hexatic order parameter ( Ψ 6 ). In addition to size disparity, we investigate the role of energy polydispersity in governing particle interactions and phase stability, where varying interaction strengths impact the local and global ordering of the system. The results clearly demonstrate a significant effect of particle size disparity on the positional and six-fold orientational order of the particles in two dimensions. Following this, the research enhances the understanding of how the structure of complex systems near the liquid-solid phase transition depends on the properties of the constituent particles and the quenching protocol, providing valuable insights for designing materials with specific surface characteristics.

Carbon fiber reinforced polypropylene-based composites with different contents of Al 2 O 3 particles were prepared by twin-screw extrusion granulation and injection molding. The effects of Al 2 O 3 particles on the mechanical properties and tribological properties of the composites were studied through various tests. The results show that with the increase in the content of Al 2 O 3 content, the elastic modulus increases, the impact strength first decreases and then increases (min at 4% Al 2 O 3 ), the COF first increases and then decreases (max at 6% Al 2 O 3 ), and the wear resistance is best at 6% Al 2 O 3 with a wear rate one-fifth of that without particles. This provides a basis for composite optimization.

Y 3 NbO 7 , a simple ternary oxide, has shown excellent high-temperature stability lately. The growing need for more durable thermal barrier coatings in extreme conditions underscores the importance of exploring materials that can resist challenges like hot corrosion. This study examines the thermal barrier properties and hot corrosion characteristics of Y 3 NbO 7 . Thermal diffusivity and the coefficient of thermal expansion were measured using laser flash technique and dilatometry respectively. The interaction with the thermally grown oxide (TGO) was evaluated by exposing the Y 3 NbO 7 powder to Al 2 O 3 at high temperatures. To demonstrate the viability of the as-synthesized powder for coating deposition, a plasma sprayed TBC architecture was developed using the Y 3 NbO 7 powder. The behavior of as-deposited coating under thermal shock was studied using thermal cycling test. Hot corrosion study was performed on Y 3 NbO 7 pellets in a species composed of 32 wt% Na 2 SO 4 and 68 wt% V 2 O 5 at 900°C. The corrosion products were examined with X-ray Diffraction and Scanning Electron Microscopy. The corrosion phenomenon was found to align with the Lewis acid-base theory, where Y 2 O 3 was preferred over Nb 2 O 5 for the acidic activity of V 2 O 5 .