Ni-based Coatings Research Articles

Effect of Coating Thickness on the Bond Strength of Cold-Sprayed Ni-Based cBN Coating on 42CrMo Substrate

Effect of Coating Thickness on the Bond Strength of Cold-Sprayed Ni-Based cBN Coating on 42CrMo Substrate

Microstructures and Properties of NbC-Reinforced Ni-Based Coatings Synthesized In Situ by Ultrasonic Vibration-Assisted Laser Cladding.

This paper aims to explore the mechanism of an ultrasonic applied field on the microstructures and properties of coatings, and clarify the evolution of the molten pool under different ultrasonic frequencies. The Taguchi experimental design method was adopted in this paper. NbC-reinforced Ni-based coatings were in situ synthesized by laser cladding to investigate the effects of ultrasonic vibration process parameters on the microstructure, pore area, microhardness, and wear resistance of the cladding layer. The results show that the pore area decreases first and then increases as ultrasonic power increases from 600 to 900 W and ultrasonic frequency from 23 to 40 kHz. On the contrary, the hardness and wear resistance increase at first and then decrease. The pore area is minimized at 800 W ultrasonic power and 32 kHz ultrasonic frequency, and the hardness is maximized at 600 W ultrasonic power and 40 kHz ultrasonic frequency. Meanwhile, the highest wear resistance can be obtained when ultrasonic power is 700 W and ultrasonic frequency is 32 kHz. Based on the phase structure analysis, the cladding layer mainly consists of FeNi3, NbC, B4C, and CrB2. Ultrasonic vibration will not change the phase composition of the layer. Combined with the varying G/R value and cooling rate, the reasons for the change in grain morphology in different areas were analyzed to reveal the evolution mechanism of the molten pool under the influence of ultrasound.

Solid Particle Erosion Wear Characteristics of WC-Reinforced Ni-Based Coating Deposited by Oxy-Acetylene Flame Welding

Solid Particle Erosion Wear Characteristics of WC-Reinforced Ni-Based Coating Deposited by Oxy-Acetylene Flame Welding

Study on the corrosion behavior and pitting mechanism of Ni-based alloy coatings in chloride ion media

Study on the corrosion behavior and pitting mechanism of Ni-based alloy coatings in chloride ion media

Wear behaviour of different nano particles coating on Al6061 substrate

ABSTRACT The tribological behaviour of Ni-based composite coatings on Al6061 substrate with secondary phase hard oxide particles like ZrO2, TiO2, and Al2O3 at different elevated temperature conditions was compared. The composite coatings with different reinforcement of nano particles were characterized by scanning electron microscopy and X-ray diffraction technique. The higher microhardness value is reported for the Ni coating with TiO2 particles and Al2O3 particles. At higher temperature limits of 120°C and 140°C Ni–ZrO2 coatings have found better specific wear rate. The Ni–Al2O3–TiO2–ZrO2 composite coating fails to achieve better properties due to higher agglomeration of the particles and dendrite growth. The Ni–Al2O3 coating showed steady wear behaviour at different temperature limits. The coefficient of friction values is found nearly similar for all the type coatings at 40°C and 120°C.

Friction and wear behavior of Ni-based alloy coatings with different amount of WC–TiC ceramic particles

Friction and wear behavior of Ni-based alloy coatings with different amount of WC–TiC ceramic particles

Understanding of microstructures and mechanical properties of thermal sprayed Ni-based coatings with Al and Mo addition

Understanding of microstructures and mechanical properties of thermal sprayed Ni-based coatings with Al and Mo addition

Corrosion behavior of Ni-based coating with Ni-coated TiC-reinforced particles by induction cladding in molten brass

In order to improve the wettability of TiC-reinforced particles with Ni-based alloy and decrease electrical resistivity of TiC-reinforced particles, Ni-coated TiC particles were fabricated by electroless plating method. Further, Ni-based coatings with Ni-coated TiC-reinforced particles on the surface of H13 steel were prepared by induction cladding. The microstructure and phase compositions of the coatings were analyzed by optical microscopy, scanning electron microscopy and X-ray diffraction. The microhardness of the coatings was measured by a microhardness tester. The corrosion behaviors of the H13 substrate and Ni-based coatings with and without Ni-coated TiC-reinforced particles in molten brass were investigated. The results showed that the addition of Ni-P layer of approximately 1.2 μm thickness on TiC particles by electroless plating significantly increased cladding temperature of Ni-based coating reinforced by TiC particles, and reduced coating thickness, defects, size of the precipitated phases and microstructure inhomogeneities. The surface microhardness of the Ni-based coating with Ni-coated TiC-reinforced particles is 168% higher than that of the substrate and 17% higher than that of the Ni-based coating. The zinc in the molten brass intruded into the H13 steel and formed mixed oxides of iron, chromium and zinc in the surface layer of the substrate with the intruded oxygen. Then the mixed oxides peeled off in the mixed oxide zoneⅡof Fe and Zn adjacent to corroded surface, while the corrosive mechanism of the Ni-based coatings involves the rapid dissolution of Ni and Si of the received coatings into the molten brass and the oxidation of Si and Zn at the corrosion interface which then peeled off in the mixed oxide zone Ⅰ of Zn and Si adjacent to the coating. The addition of Ni-coated TiC-reinforced particles refined the size of carbide and boride precipitates, preventing the formation of large corrosion pits formed in the matrix phase, and effectively slowed down uneven corrosion of the Ni-based coating.

Study of the Tribological Properties of HVOF-Sprayed Ni-Based Coatings on Ti6Al4V Titanium Alloys

In aviation, the relative sliding between titanium alloy components causes varying degrees of wear. This work aimed at reducing abrasion between titanium alloy parts and improving their service life. Three different Ni-based coatings, WC-10Ni, Ni45, and NiCr coatings, are sprayed on the surface of Ti6Al4V alloy by HVOF. Test results of the mechanical and tribological properties of such coatings show that the hardness of the Ni45 and NiCr coatings are 673 HV0.1 and 438 HV0.1, respectively, which are lower than that of the WC-10Ni coating. When subjected to a high load, the Ni45 and NiCr coatings suffer a cracking of flat particle interfaces due to the low hardness, which lowers the fracture toughness more than that of the WC-10Ni coating. The specific wear rates of the coatings gradually decrease with the increase in the coating hardness and fracture toughness. However, the cutting of Ti6Al4V by the WC-10Ni coating and the adhesion of the NiCr coating to Ti6Al4V result in severe wear loss of the Ti6Al4V friction pair. The moderately hard Ni45 coating has a weaker cutting and adhesion effect on Ti6Al4V than the WC-10Ni and NiCr coatings, respectively, and the Ti6Al4V friction pair has the lowest wear loss. This study is a viable scheme for the design of wear-resistant coatings on titanium alloy surfaces and for improving the tribological properties between titanium alloy components.

Preparation of NiCrBSi-WC/Co coatings by stable magnetic field assisted supersonic plasma spraying and its wear resistance mechanism

To enhance the wear resistance resistance of Ni-based coatings, Ni-based coatings were prepared using NiCrBSi (80 wt%) and WC/Co powders (20 wt%) as raw materials with a stable magnetic field assisted supersonic plasma spraying device at four magnetic field strength gradients. The microstructures, grain orientations and sizes of the four coatings were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and electron backscatter diffraction (EBSD) techniques. The mechanical and tribological properties of the four coatings were also investigated. The results show that the average grain size of the coating increases from 0.92 μm decreases to 0.55 μm. The composition distribution of hard phase is more uniform, and the defects such as internal pores are significantly reduced. The maximum wear loss of the coating was reduced by 66.1% after applying a stable magnetic field. The main wear mechanisms are adhesive wear and abrasive wear. This is because the steady magnetic field induces thermoelectric magnetic force (TEMF) and thermoelectric magnetic convection (TEMC) in the deposition process of the coating, resulting in uniform distribution of hard phase and fine grain. And the coating exhibits excellent wear resistance. This process provides new possibilities and methods for processing and molding of materials assisted by a steady magnetic field. • A steady magnetic field assisted supersonic plasma spraying technique was innovatively used to prepare nickel-based coatings. • The effect of magnetic field on coating properties is proved by the improvement of stable magnetic field. • The wear resistance mechanism of NiCrBSi-WC/Co coating assisted by supersonic plasma spraying with steady magnetic field was studied. • The research results not only provide new ideas for improving the defects of coatings prepared by thermal spraying technology, but also provide references for further exploration by colleagues.

Effect of WC particles preparation method on microstructure and properties of laser cladded Ni60-WC coatings

Ni60 and WC composite coatings were prepared on 17-4PH martensitic stainless steel with 30 wt% agglomeration-sintering WC (AS-WC) or 30 wt% sintering-crushing WC (SC-WC) respectively. The results show that in the AS-WC doped coating, the WC particles are more easily melted and dispersed, and a large amount of acicular (Fe, Ni, W)23C6 carbides are dispersed throughout the coating. However, in the SC-WC doped coating, the melting is quite limited and only occurs at the outer edge of the WC particles, and a small amount of (Fe, Ni, W)23C6 precipitated in the coating. Owing to this microstructure difference, the AS-WC doped coating possesses higher hardness, the microhardness reached 622.27 HV0.2 which is 25.5% higher than the normal Ni60 coating without WC, and 10.0% higher than the SC-WC doped coating. Moreover, the wear resistance test results indicate that the AS-WC doped coating has the best wear resistance compared to the SC-WC doped coating and normal Ni60 coating without WC. Those findings help us to obtain better Ni-based high hardness coatings for industrial applications.

In-situ TiC-reinforced Ni-based composite coatings fabricated by ultrasonic-assisted electrospark powder deposition

ABSTRACT In this study, a (Ti + graphite)-Ni composite powder serving as a coating material was deposited on H13 steel to fabricate an in-situ TiC-reinforced Ni-based composite coating by a new type of ESD process, which was named ultrasonic-assisted electrospark powder deposition (UEPD). The composite coating has an average thickness of approximately 45.5 μm and metallurgically bonds with the substrate. The ultrasonic vibration exerted on the UEPD electrode can effectively improve the forming quality of the composite coating, which produces better compactness and thickness uniformity as well as few defects. The microstructure mainly consisted of submicron dendrites due to the rapid solidification of the molten pool. TiC particles as reinforcements were successfully synthesized in the coating via an in-situ reaction due to their low Gibbs free energy and high melting point. The formation of refined grains and in-situ reinforcements prompts the average hardness of the coating to reach 1400.5 HV0.05, which is approximately 2.5 times that of the substrate. The tribological properties of the composite coating are greatly improved in comparison with those of the substrate. The wear rate and friction coefficient of the composite coating decrease by two orders of magnitude and 46.2%, respectively.

An in-situ synthesised TiC/Ni60A composite coating on copper by plasma cladding

ABSTRACT The in-situ synthesis of TiC reinforced Ni-based coatings were prepared on copper substrates by using precursor materials (TiFe and Cr3C2) by plasma cladding. The coating consisted mainly of γ-(Cu, Fe, Ni), TiC, CrB and Cr23C6. The generated TiC particles tend to float up to the upper part of the coating to aggregate and grow, so the TiC concentration in the upper part is larger. The hardness of the TiC composite coating is distributed in a gradient, and the average hardness is 700 HV, which is 13.0 times that of the copper matrix. The wear mechanism of TiC composite coating is abrasive wear, and the wear resistance is 13.0 times that of the copper substrate.

Microstructure and Mechanical Properties of Ni-Based Alloy Composite Coating on Cr12MoV by Laser Cladding

Cr12MoV has been widely used in the manufacture of stamping and drawing dies. In the present study, an attempt was made to improve the mechanical properties of Cr12MoV by laser cladding Ni60 alloy reinforced by WC. X-ray diffraction (XRD), scanning electron microscopy (SEM), a microhardness tester, and a friction and wear test prototype were used to analyze the macroscopic morphology, microstructure, and mechanical properties of the coating. The results showed that the coating mainly was composed of Cr-Fe-Ni, γ-(Fe, Ni), Cr23C6, Cr7C3, and W2C phases. The cladding layer presented the dendritic eutectic structure enriched Cr, Fe, and Ni. Zigzag-shaped dendrites with thicknesses of 50~80 μm of the bonding zone ensured the strong metallurgical bonding. Due to solid solution strengthening, dispersion hardening, and grain refinement, the hardness of the coating reached 745 HV, which was 3.5 times that of the substrate. The wear volume of the coating was 14 × 10−3 mm3, which was 48% lower than that of the substrate (27 × 10−3 mm3). The coating had the abrasive wear; however, the substrate had the adhesive wear besides the abrasive wear.

Investigation on Sliding Tribological Properties of Laser Cladding Alloy Coating for Subway Wheels

The wheel pair is a key component of the subway. Routes of subway conditions are more complex, while frequent starting and braking are more likely to cause wheel damage. To improve the sliding tribological properties of subway wheels, this article focused on laser-cladding technology to repair the wheel. Ni-based and Fe-based alloy coatings were prepared. The microstructure of the coatings was studied by SEM, EDS, XRD, and 3D optical morphology. The mechanical properties of the coating were studied by the Vickers microhardness tester and MFT-EC4000 reciprocating electrochemical friction and wear tester. There are mainly γ(Ni, Fe), Cr7C3, Cr23C6, and other phases in the Ni-based coating, and there are mainly γ-Fe, (Fe, Ni), (Fe-Cr-Ni) solid solution and other phases in the Fe-based coating. The hardness of the Ni-based coating is 250 HV0.7, which is essentially the same as the hardness of the substrate. The hardness of the Fe-based coating reaches a maximum of 715HV0.7. The hardness of the Fe-based coating is 2.86 times higher than the hardness of the substrate. The Fe-based coating is strengthened by the solid solution due to the existence of the solid-solution phase. The Ni-based coating in high-temperature performance is general. Its hardness and friction performance were also ordinary. The results of the study can provide theoretical and technical guidance for the application of laser-cladding technology on subway wheels.

In situ TiBX/TiXNiY/TiC reinforced Ni60 composites by laser cladding and its effect on the tribological properties

Ni-based composite coatings reinforced by TiBX/TiXNiY/TiC with different Ti6Al4V contents were precipitated on a 35CrMoV substrate via laser cladding. The phase composition, elemental distribution, and precipitated phases of the coatings were characterised using X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, and transmission electron microscopy. The mechanical and tribological properties of the cladding layer were also characterised. The results showed that the coating contained TiB2, TiC, TiB, Ni3Ti, and NiTi2 phases with uniform elemental distribution and grain refinement. A schematic of the growth model and precipitation sequence of the reinforced phases was generated. The microstructure, elemental segregation, hardness, and friction behaviour of the cladding layer were significantly influenced by the addition of Ti6Al4V. The optimal microstructure and best mechanical properties were obtained by the addition of 4 wt% Ti6Al4V, with that coating possessing a hardness, average friction coefficient, and wear volume of 770.8 HV1, 0.180 and 6132 um3, respectively.

Preparation and Properties of Pulsed Composite Coatings of Supercritical Graphene Quantum Dots

Using graphene quantum dots with unique properties as the second phase additive and utilizing the high diffusion and transfer properties of supercritical fluids, Ni-based nanocomposite coatings were prepared by pulsed electrodeposition technology. The effects of the pulse duty cycle on the microstructure, mechanical properties, and corrosion resistance of composite coatings were investigated. The results showed that the graphene quantum dots are successfully embedded in the coatings, and under supercritical conditions, a suitable pulse duty cycle can improve the surface density and sphericity of the coatings. Raman spectroscopy and carbon-sulfur analyzer test indicated that supercritical conditions can improve the quality and content of graphene quantum dots in the coatings. The graphene quantum dots composite coating prepared when the pulse duty cycle is 0.3 has more excellent mechanical properties. Its microhardness is higher, and it has a smaller friction coefficient and wear scar cross-sectional area. Tafel polarization experiments indicated that under supercritical conditions, the corrosion current density of graphene quantum dots composite coating prepared when the pulse duty cycle is 0.3 is small, which is 1.286 × 10−5 A·cm−2. The 120 h immersion corrosion study showed that no obvious corrosion occurs on the surface. Therefore, its corrosion resistance is more excellent.

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 laser spot overlap on the mechanical properties and corrosion resistance of laser-assisted electrodeposited Ni-based coatings

In this study, a laser-assisted electrodeposition method is used to prepare Ni–Co–W and amorphous Ni–P coatings for different laser scanning rates. The laser scanning rate is an important parameter as it can be used to adjust the laser spot overlap (ε) and energy distribution of the laser pulse, thereby affecting the properties and performance of the coatings. The effect of ε on the various properties of the Ni–Co–W and Ni–P coatings is explored. The experimental results show that a change in ε influences the surface morphology, mechanical properties, and corrosion resistance of the coatings. For ε = 85%, the Ni–Co–W and Ni–P coatings exhibit the best surface morphology. The Ni content of both the Ni–Co–W and Ni–P coatings is found to decrease with an increasing ε, whereas the Co and P contents are found to increase with ε. However, the residual tensile stress of the Ni–P coating fails to improve with an increasing ε. The wear and corrosion resistances of the Ni–Co–W coating increase with ε. Moreover, a change in ε affects the intensities of the (111) and (220) diffraction peaks of Ni–Co–W. For ε = 85%, both the Ni–Co–W and Ni–P coatings exhibit good wear and corrosion resistances.

Wear behavior of laser cladded WC-reinforced Ni-based coatings under low temperature

In this paper, three groups of spherical WC-reinforced Ni-based coatings were fabricated by laser cladding on EH40 steel. The microstructure, microhardness and wear mechanism of Ni-WC composite coatings at low temperatures (20 °C, 0 °C and −20 °C) were studied systematically. The effect of temperature change on friction properties of Ni-WC coatings was analyzed. The results showed that the microstructure of the coating is mainly composed of M23C6 hard phase, Cr2Ni3 compound and γ-Ni solid solution. The coating's hardness gradually increased as the WC content increased. It turns out that Ni+ 15%WC shows excellent wear resistance at −20 °C, having the minimum wear volume and lowest wear rate, which are 0.0159 mm3 and 6.36 × 10−5 mm3/N.m−1, respectively. The existence of WC and hard phase reduces the plastic deformation caused by the friction ball and the coating surface, and adhesive wear dominates the wear mechanism. As the temperature dropped from room temperature to low temperature, the wear mechanism transforms from adhesive wear to abrasive wear. Compared to those at 20 ℃ room temperature, the coefficients of friction, wear volume and wear rate all increase at low temperatures.