Scratch Method Research Articles

Double-Oxidant-Induced Slurry Reaction Mechanism and Performance on Chemical Mechanical Polishing of 4H-SiC (0001) Wafer.

Single-oxidant slurries are prevalently utilized in chemical and mechanical polishing (CMP) of 4H-SiC crystal. Nevertheless, it is a challenge to achieve a high material removal rate (MRR) and surface quality using single oxidant slurries to meet the needs of global planarization and damage-free nanoscale surface processing of SiC wafers. To solve this challenge, a novel method is proposed for SiC CMP processing using the double oxidant slurry. This slurry mainly consists of alumina (Al2O3) abrasive particles, potassium permanganate (KMnO4), potassium persulfate (K2S2O8), and deionized water. Post CMP, MRR is 1045 nm/h calculated by scratch method, and surface roughness Sa is 0.33 nm measured by 3D optical surface morphometer, with the measurement area of 868 μm × 868 μm. Both the MRR and Sa are far better than those under the single oxidant slurry condition. CMP mechanism with double-oxidant slurry conditions is elucidated by energy dispersive spectrometer and X-ray photoelectron spectrometer. Initially, the Si-C bond on the SiC wafer surface was oxidized by KMnO4, then MnO2 as the reduction product of KMnO4 can also catalyze the S2O82- to further oxidize SiC wafer surface, and eventually the oxidation layers were removed by mechanical action of nano-Al2O3 abrasive particles during CMP processing. These findings offer a pioneering approach and novel perspectives to achieve a higher MRR of 4H-SiC CMP, with potential implications for the application in high-performance SiC devices.

The effect of the introduction of B4C on the adhesive and cohesive properties of self-fluxing coatings

Wear and tear of technical equipment elements is a serious problem that negatively affects the productivity of production processes. The work analyzed the strength of cohesive and adhesive bonds of wear-resistant coatings obtained by detonation gas-dynamic spraying method based on a self-fluxing alloy, depending on the introduction of B4C particles into the composite composition. The chemical composition of the cohesive bonds of the resulting coatings and the effect of boron-containing elements on their strength were analyzed. The method of transverse scratching of transverse sections of thick coatings is a qualitative assessment of adhesive and cohesive properties and helps to determine the mechanisms of their destruction. The purpose of the work is to study the effect of the introduction of B4C particles on the adhesive and cohesive properties of coatings obtained by detonation gas-dynamic spraying based on self-fluxing NiCrBSi alloy. Methods for studying coating samples obtained by detonation gas-thermal method: scanning electron microscopy, energy dispersive analysis, optical metallographic microscopy, scratch testing. Previously, wear-resistant coatings based on self-fluxing NiCrBSi-B4C alloy have proven their effectiveness as protective coatings for centrifugal beet cutter knives. This study substantiates the feasibility of obtaining a composite based on such coatings with the introduction of boron carbide to improve its strength characteristics.

Evaluation of Hardness and Elastic Modulus of Polymer Materials Through Micro-Scratch Method: An Empirical Study

ABSTRACT A number of researchers have focused on scratch methodologies to examine the surface properties of materials. Scratch testing is primarily employed to examine tribological behavior and coating failure. This study attempts to determine the hardness (H) and elastic modulus (E) of polymeric materials via the scratch method. The research performed a progressive loading scratch test on Poly-(ether-ether ketone) (PEEK), Poly(methyl methacrylate) (PMMA), Poly-tetra-fluoro-ethylene (PTFE), polyvinyl chloride (PVC), and High-density polyethylene (HDPE). The least-squares curve fitting model was used to develop two models for assessing the H and E of materials based on indentation and scratch parameters. The H is determined by tangential force, scratch width, residual depth, and E calculated from the recovered depth and additional scratch parameters. Validation of both models indicates a maximum error of around 5%, indicating that the recently established models align well with experimental data. This study presents two robust models for assessing material surface attributes derived from a single scratch test with additional parameters.

Therapeutic Effects of Puerarin Loaded Bone Marrow Mesenchymal Stem Cell-Derived Exosomes in a Rat Model of Osteoarthritis.

Osteoarthritis (OA) is the most prevalent chronic degenerative joint disease among the aged population. The primary objective of this study was to assess the therapeutic potential of puerarin loaded bone marrow mesenchymal stem cell-derived exosomes (Pue@BMSC-Exo), and reveal their inflammatory regulating mechanisms through affecting the nuclear factor kappa-B (NF-κB) signaling pathway. In this study, exosomes derived from BMSCs were isolated and identified. Cell proliferation and migration were evaluated by CCK-8 and scratch methods. Furthermore, histological and micro-computed tomography analysis were performed to assess alterations of articular cartilage in OA rats. Results showed that BMSC-Exo and Pue@BMSC-Exo conformed with the basic characteristics of exosomes. BMSC-Exo increased the solubility of Pue and enhanced drug uptake by chondrocytes. In addition, Pue@BMSC-Exo stimulated proliferation and migration of chondrocyte, and also promoted cartilage repair by reducing matrix metalloproteinase MMP13 production and increasing type II collagen (Col2) synthesis. Furthermore, Pue@BMSC-Exo, by effectively inhibiting the NF-κB signaling pathway, reduced the production of inflammatory mediators and attenuated the release of the inflammatory marker nitric oxide (NO), ultimately ameliorating the damage of chondrocyte. These findings exhibited the potential therapeutic significance of Pue@BMSC-Exo in OA and warranted further exploration in clinical applications.

First Report of Root Rot Caused by Fusarium avenaceum and Fusarium flocciferum on Astragalus membranaceus var. mongholicus in China

ABSTRACTAstragalus membranaceus var. mongholicus (Mongolian milkvetch) is one of the most important traditional Chinese medicinal plants. In July 2021, root rot of A. membranaceus var. mongholicus was found in a field in Tongren City, Huangnan Tibetan Autonomous Prefecture, Qinghai Province, China. The aboveground part of the plants exhibited yellowing, wilting and defoliation in severe cases. Seven fungal isolates were obtained, and their pathogenicity, morphology and phylogeny were analysed. A pathogenicity test was performed using the scratch and root irrigation methods, and the results showed that all seven isolates caused root rot on inoculated plants. Based on morphological characteristics and phylogenetic analysis of multi‐locus sequences (ITS, translation elongation factor [TEF‐1α], and RNA polymerase II beta subunit [RPB2] genes), two isolates were identified as Fusarium avenaceum, and five isolates were identified as F. flocciferum. To the best of our knowledge, this is the first report of F. avenaceum and F. flocciferum causing root rot of A. membranaceus var. mongholicus in China.

Micro/Nanomechanical Characterization of ScAlMgO4 Single Crystal by Instrumented Indentation and Scratch Methods.

ScAlMgO4 (SCAM), which can be used as an epitaxial substrate material of GaN in power devices, faces the challenge of achieving a high-quality surface by ultra-precision polishing due to its brittle and easily cleaved characteristics, which are closely associated with its mechanical properties. The micromechanical properties of SCAM single crystals were evaluated by nanoindentation and microscratch tests using different indenters. The elastic modulus EIT and the indentation hardness HIT of SCAM obtained by nanoindentation were 226 GPa and 12.1 GPa, respectively. Leaf-shaped chips and the associated step-like planes of SCAM can be found in the severely damaged regime during scratching by Berkovich and Vickers indenters with sharp edges due to the intersection of intense radial and lateral cracks. The fracture toughness (Kc = 1.12 MPa·m1/2) of SCAM can be obtained by using a scratch-based methodology for a spherical indenter based on linear elastic fracture mechanics (LEFM) under an appropriate range of applied loads. An optimal expression for calculating the fracture toughness of easily cleaved materials, including SCAM, via the Vickers indenter-induced cracking method using a Berkovich indenter was recommended.

Microstructure and properties of Ni20Cr–MoS2 composite coating by subsonic flame spraying

In this study, a Ni20Cr–MoS2 composite coating was fabricated using subsonic flame-spraying technology, and the effects of adding MoS2 on the microstructure, mechanical properties, and tribological properties of the coating were studied. The microstructure analysis of the coatings revealed that the Ni20Cr and Ni20Cr-MoS2 coatings prepared by subsonic flame spraying had fewer microscopic defects and significant particle flattening. After the addition of MoS2, the porosity of the coating decreased, whereas its microhardness increased. The cohesive strength of the coating was measured using the scratch method, and it was found to be enhanced after the addition of MoS2. Moreover, in the dry friction state, compared with the Ni20Cr coating, the Ni20Cr–MoS2 coating performs better. At a load of 20 N, the friction and wear performances of the Ni20Cr–MoS2 coating were the best, and the friction coefficient decreased by 11.63 %. Based on this, the relationships between the cohesive strength and tribological properties and between the wear mechanism and scratch mechanism of the coating are discussed.

Impact Wear Behavior of the Valve Cone Surface after Plasma Alloying Treatment

Valves are prone to wear under harsh environments, such as high temperatures and reciprocating impacts, which has become one of the most severe factors reducing the service life of engines. As a lightweight ceramic, CrN is considered an excellent protective material with high-temperature strength and resistance to wear. In this study, a CrN coating was applied onto the valve cone surface via double-layer glow plasma surface metallurgy technology. The formation process, microstructure, phase composition, hardness, and adhesion strength were analyzed in detail. Impact wear tests were conducted on the valve using a bench test device. The SEM and EDS results showed that the CrN coating evolved from an island-like form to a dense, cell-shaped surface structure. The thickness of the coating was approximately 46 μm and could be divided into a deposition layer and a diffusion layer, from the outer to the inner sections. The presence of element gradients within the diffusion layer proved that the coating and substrate were metallurgically bonded. The adhesion strength of the CrN coating measured via scratch method was as high as 72 N. The average Vickers hardness of the valve cone surface increased from 377.1 HV0.5 to 903.1 HV0.5 following the plasma alloying treatment. After 2 million impacts at 12,000 N and 650 °C, adhesive wear emerged as the primary wear mode of the CrN coating, with an average wear depth of 42.93 μm and a wear amount of 23.49 mg. Meanwhile, the valve substrate exhibited a mixed wear mode of adhesive wear and abrasive wear, with an average wear depth of 118.23 μm and a wear amount of 92.66 mg, being 63.7% and 74.6% higher than those of the coating. Thus, the CrN coating showed excellent impact wear resistance, which contributed to the enhancement of the service life of the valve in harsh environments.

Retracted: Micromechanical properties characterization of 4H–SiC single crystal by indentation and scratch methods

Growth and micromachining of single crystal silicon carbide (SiC) have drawn extensive attention in wide bandgap semiconductors and remained challenging. The micromechanical properties (i.e., hardness, elastic modulus, fracture toughness), which are the key to machinability and machining quality (and therefore the yield of the grown SiC), of 4H–SiC were assessed by nanoindentation, microhardness, and microscratch tests. Consistent values of true indentation hardness of 4H–SiC can be obtained by different approaches without the need for the area function of the indenter. Accurate determination of elastic modulus (i.e., 583.5 GPa) and indentation hardness (i.e., 38 GPa) of 4H–SiC by the instrumented indentation technique requires low loads with slight indentation-induced damage. Consistent values of fracture toughness Kc of 4H–SiC were obtained by different methods such as the Vickers/Berkovich indenter-induced cracking method (2.1 MPa·m1/2), energy-based nanoindentation approaches (the critical void volume fraction of 0.062 should be used for 4H–SiC when the deterioration of indentation hardness is used), and linear elastic fracture mechanics (LEFM)-based scratch approach with a spherical indenter (2.6 MPa·m1/2). This work provides the guidance for the mechanical machining of 4H–SiC wafers and the paradigm of micromechanical characterization of brittle solids by indentation and scratch technologies.

Characterization of hydrogen embrittlement sensitivity of 18CrNiMo7-6 alloy steel surface-modified layer based on scratch method

PurposeThe purpose of this paper is to assess the hydrogen embrittlement sensitivity of carbon gradient heterostructure materials and to verify the reliability of the scratch method.Design/methodology/approachThe surface-modified layer of 18CrNiMo7-6 alloy steel was delaminated to study its hydrogen embrittlement characteristics via hydrogen permeation, electrochemical hydrogen charging and scratch experiments.FindingsThe results showed that the diffusion coefficients of hydrogen in the surface and matrix layers are 3.28 × 10−7 and 16.67 × 10−7 cm2/s, respectively. The diffusible-hydrogen concentration of the material increases with increasing hydrogen-charging current density. For a given hydrogen-charging current density, the diffusible-hydrogen concentration gradually decreases with increasing depth in the surface-modified layer. Fracture toughness decreases with increasing diffusible-hydrogen concentration, so the susceptibility to hydrogen embrittlement decreases with increasing depth in the surface-modified layer.Originality/valueThe reliability of the scratch method in evaluating the fracture toughness of the surface-modified layer material is verified. An empirical formula is given for fracture toughness as a function of diffused-hydrogen concentration.

Fracture toughness testing of metallic materials based on scratch tests

As a crucial parameter for determining a material's resistance to crack propagation, the convenient characterization of fracture toughness has attracted much attention. The scratch test is an alternate method for determining fracture toughness because it does not require notches or pre-existing cracks and only requires a minimal sample volume. In this study, the product of strength and elongation of materials is incorporated into a modified model based on the energy size effect law to calculate the fracture toughness of metallic materials using scratch tests. To validate the proposed model, scratch tests of DP800, 18CrNiMo7-6, 4140, and 4340 are performed to characterize their fracture toughness. The fracture toughness of these four metallic materials determined from scratch tests utilizing the proposed model, Akono's linear elastic fracture mechanics (LEFM) model, Akono's microscopic energetic size effect law (MESEL) model, Hubler's MESEL model, and Liu's MESEL model are compared with the results from a compact tensile test or single edge notched beam test. Our results indicate that our modified approach is applicable to metallic materials. The proposed model could be reduced to the linear elastic fracture mechanics model. This study offers an efficient way of characterizing the fracture toughness of materials using the scratch method.

Micromechanical characterization of zirconia and silicon nitride ceramics using indentation and scratch methods

Micromechanical characterization of brittle ceramics remains challenging due to the difficulty in sample preparation required by conventional tests. The micromechanical properties (e.g., elastic modulus EIT, indentation hardness HIT, and fracture toughness KIC) of ZrO2 and Si3N4 were investigated by indentation and scratch tests with different indenters (e.g., Vickers, Knoop, and Berkovich indenters) under various loads. The ratio of the true hardness by the Vickers indenter over that by the Knoop indenter is approximately a constant of 1.13 and independent of material. Elastic recovery of residual imprint by the Knoop indenter was also used to assess elastic modulus of ZrO2 and Si3N4, and modified equations were proposed. The length of Vickers indenter-induced cracking was found to be proportional to the applied load under large loads, and a modified formula for calculating fracture toughness was proposed for ZrO2 and Si3N4, which have relatively large fracture toughness of about 9 MPa⋅m1/2. The critical void volume fraction f* in the nanoindentation energy-based methods was found to linearly decrease with the exponent mf of the power-law equation used for curve fitting of the degradation of HIT or EIT with hmax. The determination of fracture toughness by scratch methodology was found to be affected by mechanical properties of material, indenter geometry, and data range.

Screening of Haliclona sp. symbiont bacteria that have the potential as MDR (Multidrug-Resistant) antibacterial from Tanjung Tiram Beach

Sponge Haliclona sp. is a type of sponge living in marine waters and is found in many areas of coral reef ecosystems. This study aimed to determine the potential for sponge Haliclona sp. obtained from Tanjung Tiram waters, Konawe, as a source of bioactive compounds of MDR (Multidrug-Resistant) antibacterial. The isolation method of Haliclona sp. symbiont was carried out by pouring and purification of Haliclona sp. symbiont using the scratch method. The purification results obtained 12 isolates of symbiont bacteria that were successfully isolated. Then the bacterial isolate was tested for its antibacterial ability against MRSA and ESBL Escherichia coli bacteria qualitatively using the agar diffusion method. Bacteria that have strong inhibitory activity are identified by morphological and biochemical tests. The results of the qualitative screening test produced four bacterial isolates that have inhibitory activity against MRSA (Methicilin Resistant Staphylococcus aureus) pathogenic bacteria with the isolate codes H3 and H8 belonging to the strong category while H4 and H10 belonging to the medium categoy. Additionally, two bacterial isolates that have inhibitory activity against ESBL Escherichia coli pathogenic bacteria with the isolate codes H3 and H8 belonging to the strong category. Based on morphological observations and biochemical tests, the H3 bacterial isolate was identified as the genus Corynebacterium spp. and the H8 bacterial isolate was identified as the genus Micrococcus spp. In conclusion, Haliclona sp. sponge exhibits promising potential as a source of microorganism producing antibacterial compounds, particulary againts MDR (Multidrug-Resistant) strains.

Senescence on Dental Pulp Cells: Effects on Morphology, Migration, Proliferation, and Immune Response

IntroductionEvidence indicates that senescence can affect essential dental pulp functions, such as defense capacity and repair, consequently affecting the successes of conservative endodontic treatments. This study aims to evaluate the effects of senescence on the morphology, migration, proliferation, and immune response of human dental pulp cells. MethodsCells were treated with doxorubicin to induce senescence, confirmed by β-galactosidase staining. Morphological changes, cellular proliferation, and migration were evaluated by scanning electron microscopy, trypan blue cells, and the scratch method, respectively. Modifications in the immune response were evaluated by measuring the genes for pro-inflammatory cytokines tumor necrosis factor alpha and interleukin (IL)-6 and anti-inflammatory cytokines transforming growth factor beta 1 and IL-10 using the real time polymerase chain reaction assay. ResultsAn increase in cell size and a decrease in the number of extensions were observed in senescent cells. A reduction in the proliferative and migratory capacity was also found in senescent cells. In addition, there was an increase in the gene expression of inflammatory cytokines tumor necrosis factor alpha and IL-6 and a decrease in the gene expression of IL-10 and transforming growth factor beta-1, suggesting an exacerbated inflammatory situation associated with immunosuppression. ConclusionsCellular senescence is possibly a condition that affects prognoses of conservative endodontic treatments, as it affects primordial cellular functions related to this treatment.

Synergistic effects of electroacupuncture and bone marrow mesenchymal stem cell transplantation on rat intrauterine adhesion： an observation.

To investigate the effects of electroacupuncture(EA) combined with bone marrow mesen-chymal stem cells(BMSCs) transplantation on the endometrium of rats with intrauterine adhesions(IUA), so as to explore the possible mechanisms underlying their combined therapeutic effects. Forty adult female SD rats were randomly divided into control, model, cell, and combined groups. The IUA rat model was established using a dual injury method of mechanical scratching and lipopolysaccharide infection. After successful modeling, on days 1, 3, and 7, rats in the model group received tail vein injection of phosphate buffered solution, while rats in the cell group received tail vein injection of BMSCs suspension for BMSCs transplantation；and rats in the combined group received BMSCs transplantation combined with EA treatment (2 Hz/15 Hz, 1-2 mA), targeting the "Guanyuan"(CV4), bilateral "Zusanli"(ST36) and "Sanyinjiao"(SP6) for 20 min daily for 3 consecutive estrous cycles. After intervention, uterine tissue was collected from 5 rats in each group. Histological analysis was performed using hematoxylin and eosin staining to evaluate endometrial thickness and glandular number. Masson staining was used to assess endometrial fibrosis area. Immunohistochemistry was performed to detect the positive expressions of vascular endothelial growth factor(VEGF), proliferating cell nuclear antigen(PCNA), and estrogen receptor(ER). Western blot analysis was conducted to determine the protein expressions of homeobox A10(HoxA10) and leukemia inhibitory factor(LIF), both key regulators of endometrial receptivity. The remaining 5 rats in each group were co-housed with male rats, and the uterine function recovery was evaluated by assessing the number of embryo implantations. Compared with the control group, the model group showed thinning endometrium(P<0.001), decreased glandular number(P<0.001), increased endometrial fibrosis area(P<0.001), reduced positive expressions of VEGF, PCNA, ER, expressions of HoxA10 and LIF, and decreased embryo implantation number (P<0.001) on the injured side of the uterus. Compared with the model group, the combined group showed a reversal of the aforementioned indicators(P<0.001, P<0.01)；the cell group exhibited thicker endometrium(P<0.001) and reduced endometrial fibrosis area(P<0.001). Compared with the cell group, the combined group showed increased endometrial thickness(P<0.01), elevated glandular number(P<0.05), significantly decreased endometrial fibrosis area(P<0.05), enhanced positive expressions of VEGF, PCNA and ER, expressions of HoxA10 and LIF in the endometrium, and a significant increase in embryo implantation number (P<0.001, P<0.05, P<0.01) on the injured side of the uterus, indicating better results than the cell group. The combination of EA and BMSCs synergistically promotes the repair of damaged endometrium, improves endometrial morphology, reduces fibrosis levels, enhances vascular regeneration and matrix cell proliferation, improves endometrial receptivity, which ultimately facilitates embryo implantation.

Advancements in Polymer Friction and Wear: A Scratch-Modeling Approach

Due to its many applications, including assessing strength, fracture toughness, and so on, the scratch method has attracted much attention in the research community. Finding the tribological characteristics of polymers, such as friction and wear, proved difficult for scratch approaches. This study tested a constant loading scratch method with a Rockwell indenter on the polymeric surface to develop an accessible wear and friction calculation model. Scratch load, speed, and passes, three primary factors, are considered to observe the polymers' response, particularly in terms of width, penetration depth, residual depth, and percentage of recovery. Considering all these scratch parameters, the experiments were conducted on five polymers: polytetrafluoroethylene (PTFE), polyether ether ketone (PEEK), polypropylene (PP), high-density polyethylene (HDPE), and polymethylmethacrylate (PMMA). The scratch characteristics are considered to calculate the friction coefficient and wear throughout the scratching process. Increased groove width, penetration depth, and residual depth and a decrease in recovery percentage are the effects of the number of scratch passes. The strain hardening caused by the multiple movements of the indenter on the same grooves causes a behavior change. With an increase in the scratch pass, the coefficient of friction decreases and stabilizes, and the volumetric wear increases, suggesting that more scratch passes will cause more material loss. This study derived two distinct models by applying the least-square curve fitting technique to evaluate friction and material wear characteristics. This model demonstrates a high degree of compatibility with the specific characteristics of polymeric materials and exhibits a significantly low margin of error.

Thermal-Mechanical Effect and Removal Mechanism of Ti-6Al-4V During Laser-Assisted Grinding

The low density and high corrosion resistance of titanium alloy make it a material with various applications in the aerospace industry. However, because of its high specific strength and poor thermal conductivity, there are problems such as high cutting force, poor surface integrity, and high cutting temperature during conventional machining. As an advanced processing method with high efficiency and low damage, laser-assisted machining can improve the machinability of titanium alloy. In this study, a picosecond pulse laser-assisted scratching (PPLAS) method considering both the temperature-dependent material properties and ultrashort pulse laser’s characteristics is first proposed. Then, the effects of laser power, scratching depth, and scratching speed on the distribution of stress and temperature field are investigated by simulation. Next, PPLAS experiments are conducted to verify the correctness of the simulation and reveal the removal behavior at various combinations of laser power and scratching depths. Finally, combined with simulated and experimental results, the removal mechanism under the two machining methods is illustrated. Compared with conventional scratching (CS), the tangential grinding force is reduced by more than 60% and the material removal degree is up to 0.948 during PPLAS, while the material removal is still primarily in the form of plastic removal. Grinding debris in CS takes the form of stacked flakes with a “fish scale” surface, whereas it takes the form of broken serrations in PPLAS. This research can provide important guidance for titanium alloy grinding with high surface quality and low surface damage.

Precise quantification of the adhesion between metallic thin films and silicon wafer

The performance and reliability of integrated circuits depend on the mechanical and electrical properties of the interfaces between thin films and the silicon wafer. One of the essential properties of the interface is its adhesion energy. However, conventional adhesion characterization methods could be further improved, especially in providing repeatable and reliable measurements. In this paper, we measured the adhesive strength of the interface between tungsten thin films and silicon wafers in micro-sized specimens using a direct push-to-pull device built into a nano-indenter. A scratch method with a transparent theoretical model was applied to quantify the same interfaces' adhesive strength, adhesion energy, and fracture resistance. Microscopic and mechanical analysis clarified the physical origin of thin film delamination. The current method precisely quantified the interfaces' adhesive strength and fracture resistance. This method is promising for sub-micron thin film designs in the semiconductor industry with its superior repeatability, reliability, and ease of operation.

Research on Nano-Titanium Modified Phenolic Resin Coating and Corrosion Resistance

Nano-titanium can be used in the field of anticorrosive coatings due to its excellent corrosion resistance. In this paper, phenolic resin was modified by nano-titanium using a physicochemical method. The nano-titanium-modified phenolic resin was used as a matrix to prepare the anticorrosive coating. The microstructures of the coatings were analyzed by Scanning Electron Microscope (SEM), X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR). Raman and UV spectrum adhesion of the coating was tested by a scratching method. The corrosion behavior was studied by electrochemical workstation and salt spray test. The results showed that the corrosion resistance of pure phenolic resin coating was significantly improved by the nano-titanium-modified phenolic resin. The coating containing 4% titanium nanoparticles exhibited the best corrosion resistance, with the highest impedance and the smallest corrosion current. The coating remained intact after 480 h of salt spray, showing the best salt spray resistance performance.

Analyzing Microstructural Features, Surface Topography, and Scratch Resistance of Innovative Nano-Composites Coated with High Velocity Air-Fuel Technology

New developments in thermal spraying processes may offer higher-quality alternatives to hard chrome plating and possibilities for hard chrome plating in a range of coating applications. These include spraying with high-velocity air fuel (HVAF) and new spray consumables. The low operating temperatures and accelerated particle velocity of the HVAF process enable investigation and development of a wide range of novel coating materials and applications. The High-velocity Air Fuel Process' quality and efficiency are primarily due to the broad combustion chamber and axial injection of the feedstock through it, as well as the relatively low combustion temperature of an air-fuel mixture and the low gas velocity that provides enough time for the mild heating of the powder particles. The current work discusses the inventive thermal spray procedure used for SAE 1008 carbon steel, a cost-effective substrate material. All of the compositions that were treated have undergone microstructure investigations. A scratch test is conducted in accordance with ASTM guidelines. Assessment of surface morphology clearly demonstrates the relationship between the evaluated parameters. According to the occurrence, scratch methods such as delamination, cracking, plastic deformation, and elastic deformation are highlighted. However, the findings of the scratch test showed that the samples' scratch resistance increased as the coating thickness rose. In comparison to samples with thinner coating, those with thicker coating demonstrated a stronger resistance to scratching. This is explained by the fact that coatings with a higher thickness and density can support the subsurface more effectively and stop cracks from scattering. This can retain the coating's integrity and stop more damage from occurring, improving scratch resistance. Better scratch resistance was displayed by the samples with denser microstructures and smoother surface morphologies. The outcome is greater scratch resistance because a higher density covering can withstand deformation and fracture better than a lower density layer. This is due to the mechanism of deformation and fracture in the coating material. This improvement in scratch resistance can be due to the composites' increased HVAF coating's hardness and adherence. The findings imply that using an HVAF coating to increase the scratch resistance of new nanocomposites may constitute a successful strategy.