Metal Matrix Composite Coatings Research Articles

Numerical and Experimental Investigations of Cold-Sprayed Basalt Fiber-Reinforced Metal Matrix Composite Coating.

The aluminum-basalt fiber composite coating was prepared for the first time with basalt fiber as the spraying material by cold-spraying technology. Hybrid deposition behavior was studied by numerical simulation based on Fluent and ABAQUS. The microstructure of the composite coating was observed on the as-sprayed, cross-sectional, and fracture surfaces by SEM, focusing on the deposited morphology of the reinforcing phase basalt fibers in the coating, the distribution of basalt fibers, and the interaction between basalt fibers and metallic aluminum. The results show that there are four main morphologies of the basalt fiber-reinforced phase, i.e., transverse cracking, brittle fracture, deformation, and bending in the coating. At the same time, there are two modes of contact between aluminum and basalt fibers. Firstly, the thermally softened aluminum envelops the basalt fibers, forming a seamless connection. Secondly, the aluminum that has not undergone the softening effect creates a closed space, with the basalt fibers securely trapped within it. Moreover, the Rockwell hardness test and the friction-wear test were conducted on Al-basalt fiber composite coating, and the results showed that the composite coating has high wear resistance and high hardness.

A review on Ti-based metal matrix composite coatings

Lightweight high-strength Ti-based metal matrix composites (Ti-based MMCs) have a multitude of application applications, e.g., biomedical engineering, aerospace, and automotive, due to their good sustainability, high specific strength/stiffness, high elevated temperature strength, high wear, and corrosion resistance. Although there are metal matrix composite coatings comprised of polymers, composite, and ceramics materials, the paper primarily focuses on titanium-based composite coatings. This review also discusses the different coating techniques including electrodeposition, thermal spray, plasma spray, vapor deposition, and laser cladding to achieve high hardness and roughness, wear resistance and corrosion resistance. Totally, we attempt to bring out Ti based materials scenario for its current applications.

Effect of Thermochemical Boronizing of Alumina Surface on the Borate Crystals Growth and Interaction with Nickel and Nickel Alloy

Wettability at the metal-ceramic interface is highly important for the development of modern composite materials. Poor wettability by metal melts restricts the use of alumina in protective metal matrix composite (MMC) coatings. In the present experimental study, the possibility to modify wetting properties of alumina by thermochemical surface boronizing was investigated. The results of SEM, EDS, XRD and XPS characterisation of surfaces revealed the formation of oxygen containing Al–B compounds identified as aluminium borates (Al18B4O33/Al4B2O9); no signs of non-oxide Al–B compounds were observed. The shape of the single splats deposited on the boronized alumina surface by the thermal spray and re-melted in the furnace revealed that significant wetting improvement by self-fluxing nickel alloy did not occur. However, the improvement of adhesion between the nickel/nickel alloy and Al2O3 surface was obtained due to formation of an intermediate layer consisting of B, O, Al and Si between the metal and ceramic surfaces at the presence of some silicon at the modified surfaces. The presented study demonstrates that the thermochemical boronizing of alumina in amorphous boron medium is a simple method to obtain a thin aluminium borate layer consisting of oriented nano-rod-like crystals, whose growing direction is predetermined by the orientation of the alumina grains’ faces at surface.

Steam and air oxidation behaviour of thermal spray chromium carbide-based composite coatings

Thermal spray chromium carbide-based composites have been widely used industrially because of their superior oxidation resistance at elevated temperatures compared to other metal matrix composite coatings. In this work, the serviceability of HVOF sprayed coatings from an atomized chromium carbide-based feedstock (Cr23C6-40NiCr) was compared with those from a conventional Cr3C2-25NiCr agglomerated and sintered feedstock. Coatings were exposed to 540 °C and 610 °C for 168 h in both air and steam environments. These conditions are indicative of industrial power plant working conditions to assess their real-time performance. Quantitative Rietveld analysis of the Cr23C6-40NiCr coating XRD patterns indicated a comparable concentration of Cr23C6 in both the powder and coating, implying minimal carbide dissolution. However, the Cr3C2 content in the conventional Cr3C2-25NiCr coating was markedly reduced compared to the initial powder composition, indicating that carbide dissolution occurred to a greater extent. Air oxidation led to the formation of coarse surface oxide, due to the initial formation of Ni-based oxides before a continuous Cr2O3 layer could develop underneath. A notably finer and more uniform oxidized surface composed only of Cr2O3 was formed during steam treatment across both coating types. More importantly, the oxide scale was intact and crack-free in Cr23C6-40NiCr compared to Cr3C2-25NiCr. Moreover, despite Cr23C6 being the main carbide phase and the high binder content (40%NiCr), the microhardness of the Cr23C6-40NiCr coating was comparable to that of the conventional Cr3C2-25NiCr coating, both in the as-sprayed and heat exposed states.

The structure and properties of laser-cladded Inconel 625/TiC composite coatings

Abstract The article presents the research in the field of production of metal–matrix composite coatings using laser cladding technology. The general purpose of producing composite coatings is the improvement of wear resistance of the material surface. In this research, Inconel 625 was used as a matrix material. Nickel-based superalloys are used in several industries for unique applications because they possess a number of beneficial properties including high tensile and fatigue strengths and resistance to high-temperature corrosion in aggressive environments. However, for some applications, this alloy shows insufficient wear resistance of the surface; therefore, for the tests, Inconel 625-based composite coatings were produced with the addition of 10 vol.%, 20 vol.%, and 40 vol.% of titanium carbide (TiC) particles as reinforcement. In general, the addition of TiC particles had a positive effect on the erosion resistance of the surface. The aim of the current research was to test the influence of TiC particle reinforcement of Inconel 625 laser-cladded coatings on corrosion resistance of the surface. For the tests, the laser-cladded composite coatings with uniform phase distribution were produced. The proceeded tests included penetrant tests, macrostructure and microstructure analysis, X-ray diffraction (XRD), and microhardness and corrosion resistance tests. The results showed that using laser cladding, TiC-reinforced Inconel 625 uniform composite coatings may be produced. The addition of TiC particles caused microstructure changes in the Inconel 625 matrix and an increase in hardness. The addition of TiC particles had a negative influence on Inconel 625 corrosion resistance, but with the increased composite coating homogeneity, the corrosion resistance improved.

Comparative study on the wear resistance and corrosion resistance of NiW and NiCoW composite coatings with micro- and nano-SiC particles

Wear resistance and corrosion resistance are important properties to evaluate the quality of metal matrix composite coatings. In this paper, micro-SiC (mSiC), and nano-SiC (nSiC) particles enhanced NiW and NiCoW composite coatings are direct current electrodeposited from sulfate-citrate electrolytes with SiC concentration from 0 to 80 g/L. This work provides a comparative study on the surface morphology, microhardness, wear resistance and corrosion resistance of NiW/mSiC, NiCoW/nSiC and NiCoW/mSiC composite coatings. Results show that mSiC and nSiC have a little effect on the microhardness of NiW and NiCoW coatings, which are all around 600 HV 0.05 . While high content of the incorporated mSiC particles can reduce the oxidative wear and peeling effect, then greatly decrease the wear rate of NiCoW composites from 15×10 -6 to 3×10 -6 mm 3 ∙m -1 ∙N -1 . In addition, the corrosion resistance of NiW and NiCoW can also be improved by mSiC and reaches the best properties at the SiC concentration of 10 g/L. In contrast, nSiC do not contribute to obvious enhancement of wear resistance and corrosion resistance due to the lower content of nSiC particles. It is notable that the corroded NiCoW/SiC and NiW/SiC coatings exhibit a novel network-like morphology. And the size of meshes of the network-like structure is related to the anti-corrosion property. • Micro-SiC and nano-SiC enhanced NiW and NiCoW coatings were electrodeposited • Micro-SiC are better for improvement of wear and corrosion resistance than nano-SiC • Micro-SiC can highly decrease oxidative wear and peeling of NiW and NiCoW coatings • A network-like nanostructure appears on the corroded NiW and NiCoW composite coatings

Oscillating Laser Post-Processing of NiCrCoFeCBSi/WC Thermally Sprayed Coatings.

In the present experimental study, the transverse oscillating laser beam technique was applied for the post-melting of metal matrix composite coatings, thermally sprayed with nickel-based self-fluxing NiCrCoFeCBSi alloy and 40 wt.% WC, to improve their hardness and wear resistance. The study was conducted using the single module optical fiber laser at 300 W power, >9554 W/cm2 power density, 250-1000 mm/min laser speed, 1 mm and 2 mm transverse oscillation amplitude. Scanning electron microscopy, energy dispersive spectroscopy, Knop hardness measurements, and "Ball-on-disc" dry sliding tests were conducted to study the effect of the processing parameters on the molten pool geometry and microstructure, hardness, and tribology of the processed layers. Oscillating laser processing with an amplitude of 1 mm, 250-750 mm/min laser operating speed, and sample preheating to 400 °C gave a satisfactory result: wide and shallow molten pools of ~200-350 μm in depth, hardness between ~1100 and 1200 HV0.2 and minimum cracks obtained. The coatings obtained with laser beam oscillation and preheating, and ~1150 HV0.2 hardness showed an improvement in the wear resistance and friction coefficient (~0.33) of ~2.9 times and ~20%, respectively, compared with the respective values of the coatings remelted in furnace.

Investigation of Structure Formation and Tribotechnical Properties of Steel Plasma Coatings After Chemical-Heat Treatment and Liquid-Phase Impregnation

Abstract The paper is focused on the studies of the microstructure development and physical and mechanical properties of metal-matrix composite coatings based on steel 11Cr18MoWCu deposited using plasma and galvanoplasma methods. The expediency of combining gas-thermal spraying processes of plasma coatings with open porosity up to 16%–18%, with their subsequent thermodiffusion saturation (chromium plating) or liquid-phase impregnation with eutectic alloys of previously applied Ni–B galvanic layer, is shown. The study of the tribotechnical properties of the proposed coatings showed a significant improvement in their performance under conditions of various types of intensive wear, as well as in corrosive environments.

A review on wear characterization of electrodeposited nickel matrix composites

Corrosion resistance across a wide temperature range, increased physical, mechanical, and tribological capabilities, variable surface hydrophobicity, and an attractive appearance are all advantages of electrodeposited metal matrix composite coatings (MMCs). As a result, several studies have been conducted to evaluate the various physical, mechanical, biochemical, electrochemistry, and thermodynamics characteristics of nanocrystalline composite material, generated on a variety of substrates with numerous electrodeposition settings. In this review paper, the current literatures on wear rate of electrode-posited Ni-based coatings made of composite materials are being reviewed. More specifically, the research papers on weight management, wear resistance, coefficient of friction, surface roughness, hardness and associated deterioration methods has been identified and reviewed. The observations showed that nano-composite films offer substantially superior wear resistance than magnesium alloys and pure nickel coatings due to the diffraction stiffening and grain refining effects. Also, abrasion is the main wear process for nano-composite coatings, whereas adhesion wear is the primary wear arrangement for magnesium alloys and major wear mechanism for pure nickel coatings is exfoliation wear.

Effect of Particle Size on Ceramic Particle Content in Cold Sprayed Al-Based Metal Matrix Composite Coating

Effect of Particle Size on Ceramic Particle Content in Cold Sprayed Al-Based Metal Matrix Composite Coating

Electrochemical corrosion performance of friction stir processed cold spray metal matrix composite coatings on AZ31B magnesium alloy under sodium chloride environment

The main objective of this investigation is to study the effect of friction stir processing (FSP) on the surface integrity and corrosion resistance of low-pressure cold sprayed (LPCS) aluminium alloy/aluminium oxide metal matrix composite (Al-Al2O3 MMC) coating deposited on AZ31B magnesium alloy for aerospace and automobile applications. The Al-Al2O3 MMC coating was developed on AZ31B magnesium alloy using a LPCS system. FSP was performed on the MMC coating using a stirring tool made of H13 tool steel. The structural integrity of the coating was analyzed using scanning electron microscopy (SEM). The phase analysis of coating was studied using x-ray diffraction (XRD). The potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests were performed to study the corrosion resistance of cold sprayed and FSPed samples. Results showed that FSP improved the structural integrity of MMC coating. Both the EIS and potentiodynamic polarisation test results reveal that FSP treated samples provide superior corrosion resistance than cold sprayed samples. This is due to the increase in interfacial bonding between matrix and reinforcement phase. The degree of separation and dispersal of alumina in the Al alloy matrix is increased through the shear force generated by the FSP tool on the coating surface.

Effect of Hard Particles on Magnetic Barkhausen Noise in Metal Matrix Composite Coatings: Modeling and Application in Hardness Evaluation

The hard particles in metal matrix composite (MMC) coatings can greatly improve the hardness of materials and further affect the mechanical properties. How to accurately evaluate the hardness of MMC coatings using a nondestructive method is always a challenge. The magnetic Barkhausen noise (MBN) has been proven to be very sensitive to the variations of microstructure. Thus, a theoretical model is established in this article to describe the effect of hard particle content on the magnetic Barkhausen activity, based on which the hardness can be evaluated by the MBN method. In this model, the key magnetic parameters of Jiles–Atherton (J-A) theory, the pinning parameter <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$k$ </tex-math></inline-formula> and reversibility factor <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$c$ </tex-math></inline-formula> , are dependent on the number and the interparticle distance of hard particles. A stochastic process of Barkhausen activity combined with J-A theory is then described to deduce the variations of hysteresis loop and MBN signals with hard particle contents in MMC coatings. The results show that the peak value of root mean square (rms) of MBN signals decreases, while the full-width at half-maximum (FWHM) increases with the increase in weight percentage of hard particles. Based on the leave-one-out cross-validation (LOO-CV) method, the variation trends of MBN characteristics can be described well by the second-order polynomial fitting. Also, the prediction error between experiment and theory is 15.28% and 17.40% for normalized rms peak value and FWHM, respectively. The variation mechanism of MBN signals is attributed to the anisotropic hypereutectic structure with flower stripe consisting of solid solution and secondary strengthening phase near hard particles, which promotes the pinning sites and hinders the domain wall movement. When the hard particle content is high, especially above 30%, the double peak distortion characteristics of MBN signals are easily induced by the different response of matrix alloy to the applied magnetic field in comparison to the magnetically hard phases in a hypereutectic structure. Finally, the complicated relationship between MBN characteristic values and hardness is deduced by using the hard particle content as an intermediate variable. The results show that our proposed theoretical model and evaluation method in this article can characterize the hardness of MMC coatings well.

Microstructure evolution and mechanical properties of thermally sprayed coating modified by laser remelting and injection with tungsten carbide

The forming quality of thermally sprayed coatings is often severely impacted by inherent defects, including porosity, microcracks, and mechanical bonding. The poor adhesive strength hinders the utilization of thermal spray technology when fabricating ceramic-reinforced metal matrix composite coatings (MMCCs). Thus, in this study, a negative defocus laser remelting and injection method (LRI) is introduced to modify a thermally sprayed coating with WC ceramics. The microstructure and mechanical property (microhardness, elastic modulus, and wear resistance) evolution of a LRI-modified WC reinforced composite coating is systematically characterized and compared with that for an as-sprayed coating. The LRI method is proven to improve the inherent defects of the initial coating and avoid severe reactions and dissolution of reinforced particles at high temperatures, and can be used to form a high-quality composite coating with a maximum strengthening effect of the ceramic particles. Compared with the initial coating, the elastic modulus and microhardness of the LRI coating are increased by 57.22% and 111.06%, respectively, whereas the abrasion rate is decreased by 54.33%.

Process optimization, microstructure and microhardness of coaxial laser cladding TiC reinforced Ni-based composite coatings

Since the precursors for coaxial laser cladding (LC) can be easily customized, less waste, and flexibly applied to the surface of complex parts, LC is a practical and promising approach to fabricate metal matrix composite (MMC) coatings for surface modification or repair compared with selective laser melting, preset powder cladding, gas tungsten arc welding. The precursors for LC MMC coatings are composed of an optimized single alloy powder, hard particles or related elements. However, the process for LC MMC coatings is the same as that for single alloy powder. Since the added materials usually affect the quality of the laser beam, the flow characteristics and the solidification process of the melt pool, the process parameters for LC MMC coatings are often not optimal. Therefore, the coarse TiC particles were firstly added to the commercial Ni45 powder, and the Taguchi method and empirical statistical model are employed to optimize process parameters for LC MMC coatings. A reliable processing map for customized precursors was obtained. Finally, the single-layer multi-track TiC-reinforced MMC coatings were fabricated to verify the correctness of mathematical models. The suitable process parameters combination for LC Ni-based MMC coatings are laser powder of 380 W, scanning speed of 5 mm/s, and powder feed rate of 243.7 mg/s. Moreover, the microhardness of the optimized MMC coating is about 520 HV0.3, which is about 2.5 times that of the substrate.

Electrodeposition and Characterization of Ni-Cu Alloy and Submicron-Sized CeO2 Reinforced Ni-Cu Metal Matrix Composite Coatings

Electrodeposition and Characterization of Ni-Cu Alloy and Submicron-Sized CeO2 Reinforced Ni-Cu Metal Matrix Composite Coatings

A Review on the Enhancement of Mechanical and Tribological Properties of MCrAlY Coatings Reinforced by Dispersed Micro and Nanoparticles

The application of metal-matrix composite coatings for protecting and improving the service life of sliding components has demonstrated to have the potential of meeting the requirements of a diverse range of engineering industries. Recently, a significant body of research has been devoted to studying the mechanical and tribological performance of dispersion-strengthened MCrAlY coatings. These coatings belong to a class of emerging wear-resistant materials, offering improved properties and being considered as promising candidates for the protection of engineering structural materials exposed to tribological damage, especially at elevated temperature regimes. This paper attempts to comprehensively review the different reinforcements used in the processing of MCrAlY-based alloys and how they influence the mechanical and tribological properties of the corresponding coatings. Furthermore, the major fabrication techniques together with their benefits and challenges are also reviewed. Discussion on the failure mechanisms of these coatings as well as the main determining factors are also included. In addition, a comprehensive survey of studies and investigations in recent times are summarized and elaborated to further substantiate the review.

WC-Fe metal-matrix composite coatings fabricated by laser wire cladding

Tungsten carbide reinforced iron-based metal-matrix (WC-Fe) composite coatings, for the first time, have been fabricated on carbon steel substrate by the laser wire cladding with a novel type of Fe-based tubular cored wire. The processing characteristics have been systematically investigated by cladding of single tracks at varying operating parameters. In order to guide the actual production and predict the influence of different parameters on the typical processing characteristics in terms of wire stubbing transfer, wire plunging transfer, and liquid spreading transfer mode, a process window has been established. The experimental results show that the unmelted defects can be found in the coatings produced in the stubbing transfer mode, while most of the coatings obtained in the liquid spreading transfer mode have a high dilution degree (>13 %) and a low content of retained particles (<15 %). Only the coatings fabricated in the wire plunging transfer mode possess a low dilution ratio (<13 %) and a high volume fraction of retained particles (15–26 %). The microstructural evolution in these coatings have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). The ex-situ tungsten carbide particles are partially dissolved and interact with the matrix in the molten pool, resulting in the M6C (Fe3W3C) reaction layer around the retained particles. The faceted M6C carbides and the herringbone eutectic M6C carbides are found to be the primary precipitations in the coatings, combined with the presence of retained particles, the wear resistance of the WC-Fe coatings is significantly improved.

Investigation of Ti/TiB2 System Composite Coatings Sprayed by Microplasma Method

The present work studies Ti/TiB2 system of metal matrix composite powders and coatings obtained on their basis by microplasma spraying. Ti/TiB2 is the system of potentially perspective materials being operated in aggressive environments. Morphology of the micro-grinding of the composite powder and coating was investigated by a scanning electron microscope, with the distribution assessment of the reinforcing component. The phase composition and its evolution in the composite powder and coating were also studied.

Effect of Electromagnetic Field on Wear Resistance of Fe901/Al2O3 Metal Matrix Composite Coating Prepared by Laser Cladding.

Fe901/Al2O3 metal matrix composite (MMC) coatings were deposited on the surface of 45 steel via electromagnetic field (EF)-assisted laser cladding technology. The influences of EF on the microstructure, phase composition, microhardness, and wear resistance of the Fe901/Al2O3 MMC coating were investigated. The generated Lorentz force (FL) and Joule heating due to the application of EF had a positive effect on wear resistance. The results showed that FL broke up the columnar dendrites. Joule heating produced more nuclei, resulting in the formation of fine columnar dendrites, equiaxed dendrites, and cells. The EF affected the content of hard phase in the coatings while it did not change the phase composition of the coating, because the coatings with and without EF assistance contained (Fe, Cr), (Fe, Cr)7C3, Fe3Al, and (Al, Fe)4Cr phases. The microhardness under 20 mT increased by 84.5 HV0.2 compared to the coating without EF due to the refinement of grains and the increased content of hard phase. Additionally, the main wear mechanism switched from adhesive wear to abrasive wear.

Enhancing the Corrosion Resistance of Low Pressure Cold Sprayed Metal Matrix Composite Coatings on AZ31B Mg Alloy through Friction Stir Processing

To improve the corrosion resistance of Mg alloy, Al alloy/alumina metal matrix composite (MMC) coatings were formed by low pressure cold spraying (LPCS) technology followed by post friction stir processing. The phase structure, microstructure, and corrosion properties of the cold-sprayed metal matrix composite coatings before and after friction stir processing were investigated. The effect of the friction stir process (FSP) on the corrosion characteristics of MMC coatings at 3.5 weight percent of NaCl solution was explored using a Tafel polarisation plot. Microstructural studies were examined to investigate the electrochemical behaviour of the cold spray (CS) and FSPed MMC coatings. The results demonstrated that an enhancement in corrosion protection of the MMC deposits occurred at the 1st and 2nd runs of FSP, with superior corrosion performance observed at the 2nd run of FSP. The enhanced surface state is the primary enhancement mechanism of the electrochemical properties of the FSPed MMC coatings. For the higher run of FSP (3rd run), the electrochemical performance of the specimens was lower owing to the amalgamate action of the enhanced surface state with the aggravated interface of interior deposits.