Fe-based Composite Coatings Research Articles

Correction: Comparison of Tribological Behavior of Hard Faced Fe-Based Metallic Composite Coatings Sprayed Using HVOF

Correction: Comparison of Tribological Behavior of Hard Faced Fe-Based Metallic Composite Coatings Sprayed Using HVOF

Comparison of Tribological Behavior of Hard Faced Fe-Based Metallic Composite Coatings Sprayed Using HVOF

Comparison of Tribological Behavior of Hard Faced Fe-Based Metallic Composite Coatings Sprayed Using HVOF

Effect of mechanical vibration on microstructure and performance of Fe-based composite coatings fabricated by underwater laser deposition technology

To solve the problem of the uneven composition and poor performance caused by water environment during the underwater laser deposition process, the mechanical vibration assisted underwater laser deposition technology was innovatively proposed, and Fe-based composite layer was successfully prepared. The microstructure, grain type and properties of Fe-based composite layer with and without mechanical vibration were studied and compared. The results showed that the mechanical vibration broke the grain and promoted the formation of more nuclei, which reduced the average grain size by 13.48 %. The solute located in the grain gap was transferred to the liquid molten pool by mechanical vibration, which reduced the Ti content in the intergranular precipitated phase Fe2Ti and made the Fe2Ti from coarse continuous distribution to fine discontinuous distribution. Additionally, the mechanisms of mechanical vibration promoting the performance of the composite were analyzed comprehensively. Compared with the composite without mechanical vibration, the composite with mechanical vibration had good corrosion resistance after 30 days of immersion, and the tribo-corrosion resistance was also improved. With the aid of mechanical vibration, the ultimate tensile strength and elongation of the composite were increased by 11.30 % and 22.08 %, respectively, due to the formation of recrystallized grains, high density high-angle grain boundaries, and fine intergranular precipitate. This study was expected to provide a new way to regulate the microstructure and properties of the underwater laser deposition layer, and promote the application of underwater laser deposition technology in marine engineering equipment.

Microstructure evolution mechanism of WB-doped Fe-based amorphous composite coating under proton beam irradiation

Fe-based amorphous coatings exhibit exceptional irradiation resistance attributed to their distinct topologically disordered structure, rendering them highly attractive for advanced nuclear energy applications. The incorporation of WB secondary phase doping can notably alter the coating to enhance its operational safety. In this investigation, three different Fe-based composite coatings, with varying WB doping levels of 5 %, 10 %, and 15 % were fabricated through the High-Velocity Oxy-Fuel (HVOF) spraying technique. Irradiation tests were conducted at room temperature utilizing a proton beam with an energy of 1.52 MeV to simulate neutron irradiation environment in a nuclear reactor. The microstructure evolution before and after irradiation was systematically investigated with XRD, SEM, and TEM techniques. The results demonstrated that proton irradiation induced free volume, crystallization and H bubbles evolution. The doping of WB diminished the proton implantation dose threshold for segregation in irradiation plateaus while enhancing the growth of precipitates around the damage zone by inducing the production of M23C6 carbides and, at the same time, increasing the probability of H bubble nucleation and growth. These findings provide insights for iterative updates in Fe-based amorphous materials, informing their further development and application.

Fracture toughness and cavitation erosion behavior of Fe-based amorphous composite coatings with Ni-coated Al2O3 addition

Fe-based amorphous composite coatings were prepared on 304 stainless steel substrates using atmosphere plasma spraying (APS), aiming to investigate the effect of Ni-coated Al2O3 particles addition on fracture toughness and cavitation erosion behavior of Fe-based composite coatings. The microstructure, phase composition, elastic modulus, microhardness and fracture toughness of the coating were characterized using scanning electron microscopy with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), microhardness tester and nanoindentation. The cavitation erosion behavior of Fe-based coatings was investigated by ultrasonic vibration cavitation method. Fe-based amorphous composite coatings exhibit a characteristic lamellar microstructure and reveal the presence of amorphous phases along with α-(Fe, Cr), NiO, Ni and Al2O3 crystalline phases. When the content of Ni-coated Al2O3 in coating increases from 0 wt% to 3 wt%, there is slight deterioration in porosity from 3.64 % to 4.75 % and fracture toughness from 2.579 MPa·m1/2 to 2.392 MPa·m1/2, yet an increase in microhardness from 925.4 HV0.5 to 1090.3 HV0.5. The composite coating with 3 wt% Ni-coated Al2O3 demonstrates the peak cavitation resistance and its cumulative mass loss is significantly reduced by 36.4 % compared to the pure Fe-based coating. The cavitation erosion failure of Fe-based amorphous composite coatings is predominantly characterized by the brittle fracture mechanism. The fundamental process driving cavitation erosion damage involves the material peeling and coating delamination instigated by intense micro-jet impact and shock wave propagation. The proposed Fe-based amorphous composite coatings can be applied to improve the anti-cavitation performance of components in contact with high-speed fluids, such as ship propellers and centrifugal pump blades.

Effect of microstructure of overlapping regions on the wear/corrosion resistance performance of laser cladded Fe-based amorphous composite coatings

The issue of crystallization during the laser cladding process poses a significant challenge to the application of amorphous coatings. In order to explore the practical application of Fe41.5Co12.2Cr7.4Mo37.3C0.3B0.5Y0.4Al0.4 (at.%) amorphous composite coatings, this study fabricated coatings with different scanning speeds. The aim was to delve into their crystallization processes and assess the consequential effects on the coatings’ properties. The study revealed that crystallization predominantly occurs in the coatings’ overlapping region, which can be divided into two zones: the overlapping transition zone (OTZ) and the overlapping heat affected zone (OHAZ). The crystallization extent within the OHAZ is higher than in the OTZ, attributable to the disparate cooling rates characteristic of each region. With increasing scanning speed, the OHAZ gradually increases and the OTZ decreases. The coating prepared at 2000 mm/min has excellent corrosion resistance (polarization resistance 10,814.2 Ω·cm2) and wear resistance (wear rate (8.88±0.378)×10–6 mm3/N·m).

Effect of N on microstructure, nucleation mechanism and mechanical performance of (Ti, Nb) C particles in Fe-based composite coating via plasma spray welding

Compared with the coating of Ti-Nb-C system, the coating of Ti-Nb-C-N system shows better mechanical properties, especially wear resistance. Therefore, this investigation was focus on the in-situ (Ti, Nb) C reinforced Fe-based composite coatings (D1 composite coatings) and in-situ (Ti, Nb) (C, N) reinforced Fe-based composite coatings (D2 composite coatings) which were created on high strength steel via plasma spray welding (PSW) technology in the environment with nitrogen and without nitrogen, respectively. The two coatings were compared to explore nucleation mechanism of nitrogen on (Ti, Nb) C particles, grain size, particle morphology and the influence on the mechanical performance of coatings. The findings showed that the changes in the typical microstructure morphology and the shape of the reinforced particles of the two coatings were not obvious. However, the heterogeneous nucleation sites of (Ti, Nb) C were provided by introducing nitrogen. In addition, the introduction of nitrogen could refine the grains of D1 composite coatings. As a result, the average grain size of D1 composite coatings decreased by an order of magnitude, and the crystal orientation of the grains in the composite coatings showed better isotropy. The average microhardness of D2 composite coatings was 967.52 HV1, which was 1.5 times of the average microhardness of D1 composite coatings. The wear loss of D2 composite coatings was 0.4 mg, which was only half of that of D1 composite coatings (0.8 mg).

Effects of Cr and Mo content on the microstructure and properties of Fe-based amorphous composite coatings by laser cladding

In this study, we successfully produced Fe-based amorphous composite coatings on the surface of 45 steel using laser cladding technology, and the impact of the relative content of Cr and Mo elements on the microstructure, hardness, and wear resistance of composite coatings has been investigated. The results show that the microstructure of the coating changes from dendrite to amorphous nanocrystalline when the content of Cr and Mo is 20 and 15 wt. %, respectively. However, when the Mo element continues to be added, elemental segregation will be caused, resulting in a large number of brittle Fe–Cr–Mo intermetallic compounds and MoSi2 ceramic phases in the coating. Therefore, the appropriate element ratio can not only increase the amorphous phase content in the coating but also prevent elemental segregation. Among the three types of amorphous composite coatings studied, the Fe45Cr20Mo15B10Si10 (wt. %) composite coating exhibited the most favorable performance, primarily due to its highest amorphous content (43.33%). Through the interaction of the amorphous phase, α-Fe, Fe–Cr solid solution, and a small proportion of intermetallic compounds, this coating achieved a hardness of 1282.8 HV0.2, approximately five times that of the 45 steel substrate, and demonstrated superior wear resistance.

Microstructure, Mechanical Properties, and Tribological Properties of Fe-Based Composite Coatings Reinforced with WC-Co and Cr3C2

Microstructure, Mechanical Properties, and Tribological Properties of Fe-Based Composite Coatings Reinforced with WC-Co and Cr3C2

Improving wear and corrosion resistance of HVAF sprayed 316L stainless steel coating by adding TiB2 ceramic particles and CeO2

316L stainless steel is used in a wide variety of corrosion-prone locations. However, its low hardness and poor tribological properties limit its application under heavy wear conditions. In this study, 316L Fe-based composite coatings co-doped with TB2 hard phases and rare-earth CeO2 exhibited excellent wear and corrosion resistance. Firstly, 316L-TiB2 cermet powder and (316L-TiB2)/CeO2 composite powder with high sphericity and density were prepared by high energy ball milling (HEBM), spraying drying granulation (SD), plasma spheroidization (PS) process. Then, 316L coatings, 316L-TiB2 and (316L-TiB2)/CeO2 cermet coatings were deposited by high velocity air fuel (HVAF) spraying. Finally, the effects of TiB2 and CeO2 additions on the microstructure, wear and corrosion behavior of the coatings were investigated. The results showed that TiB2 hard particles and CeO2 were uniformly distributed in the HVAF sprayed 316L-TiB2 and (316L-TiB2)/CeO2 coatings. The wear resistance of the coating prepared by 316L Fe-based composite powder with TiB2 and CeO2 is significantly improved. The hardness of the (316L-TiB2)/CeO2 composite coating was increased from 269 Hv0.3 to 826 Hv0.3 for the pure 316L coating, while the volumetric wear rate was only 3.6 % of that of the pure 316L coating (110 × 10−5 down to 4 × 10−5 mm3/N). Electrochemical tests show that the corrosion resistance of the coating decreases with the addition of TiB2 alone, but it can be improved by doping CeO2. The 316L Fe-based coating prepared by adding TiB2 and CeO2 can significantly improve the wear resistance of the coating, while the corrosion resistance decreases only slightly.

Microstructure evolution, wear and corrosion behaviour of (Nb, V)C-reinforced Fe-based composite coatings by laser cladding

Five Fe-based composite coatings with different weight ratios of Nb were prepared by laser cladding on 0Cr13Ni5Mo substrate. As the Nb content imposes, the NbC content gradually increases; the microstructure was refined; and the NbC morphology changed from quadrangle carbides to petaloid and papilionaceous carbides. Meanwhile, the microhardness and wear resistance of the composite coating gradually improve. The S3 coating exhibited a high microhardness of approximately 610 ± 12.2 HV and an excellent wear resistance. The S3 coating showed the highest corrosion resistance in 3.5 wt-% NaCl solution with Ecorr and Icorr of −179.3 mV and 9.258 × 10−8 A/cm2, respectively. The improvement in the corrosion resistance could be attributed to the fact that the forming NbC would consume amounts of C in the matrix; thus, the Cr atoms were released from its carbide state, and then dissolved in the matrix.

Nucleation mechanism, particle shape and strengthening behavior of (Ti, Nb) (C, N) particles in Fe-based composite coatings by plasma spray welding

This study aimed to determine the nucleation mechanism, particle shape, and strengthening behavior of (Ti, Nb) (C, N) particles in Fe-based composite coatings. In this study, an in-situ technique combined with a plasma spray welding process was proposed to obtain a coating with in-situ (Ti, Nb) (C, N) particles. Composite coatings were successfully prepared on low-alloy steel by plasma spray welding using a mixture of Fe-based, Ti and Nb powders. N gas was used to provide the N atoms. The microstructural analysis results indicated that the reinforced particles transformed from irregular dendritic into massive and spherical particles, and then into spherical and lath particles, as the atomic ratio of Ti/Nb decreased. During solidification, TiN nucleated preferentially and Ti (C, N) particles were formed sequentially. Subsequently, NbC nucleated and grew with Ti (C, N) as its core, and (Ti, Nb) (C, N) particles were formed at the end. The microhardness values of these composite coatings were 680–970 HV, whereas that of low-alloy steel was 174 HV. The wear resistance of the composite coatings increased as the Ti/Nb atomic ratio decreased. The composite coating had the highest average microhardness and the best wear resistance when Ti/Nb = 1:3. Its average microhardness was five times more than that of the low-alloy steel. In addition, the mass loss of the composite coating was 0.4 mg, which is only one-sixth that of the low-alloy steel (2.4 mg). The main reason for this was the in-situ formation of (Ti, Nb) (C, N) particles, which were evenly distributed in the composite coatings.

Effect of temperature on wear and friction performance of WC-Co and Cr3C2 reinforced with 17-4PH Fe-based composite coatings

Effect of temperature on wear and friction performance of WC-Co and Cr3C2 reinforced with 17-4PH Fe-based composite coatings

Tribological properties of laser-cladded Fe-based amorphous composite coatings under dry and lubricated sliding

Fe-based amorphous composite coatings are promising surface coating materials, because of their low cost, high hardness, and superior wear resistance. In the present study, Fe-based composite coatings with various amorphous contents (35.9–59.3%) were deposited onto 1045 steel via laser cladding, and the influence of laser-cladding parameters on the amorphous content was analysed. The cross sections of the coating layer and ground coating surface were then characterised in terms of the microstructure, phase composition, amorphous content, grain size, and microhardness. Importantly, the tribological properties of coatings with various amorphous contents under both dry and lubricated sliding conditions with light and heavy loads were systematically investigated. The microstructure of the crystalline/amorphous mixture was found to be a function of the temperature gradient, cooling rate, and chemical composition. The high microhardness was related to the amorphous content and grain size. The tribological properties were found to be insensitive to the amorphous content under both dry and lubricated conditions under light and heavy loads. The manifold morphologies of the wear tracks and the transition of the wear mechanism were the result of the combined effects of the amorphous content, phase composition, and size and distribution of the crystalline phase.

Design, fabrication, microstructure and properties of in-situ synthesized TiC reinforced stainless steel matrix composite coating by laser cladding

TiC particle reinforced Fe-based composite coatings have excellent properties, which are broadly considered as promising high-performance coatings/components. In this study, we designed and fabricated in-situ synthesized TiC reinforced stainless steel matrix composite (SMC) coatings through adding Cr3C2 and Ti powders and subsequently carried out by laser cladding technique. Experimental results show that TiC particles are uniformly distributed within the dendrites. Based on the microstructure observation, thermodynamics calculations and dynamics assumption, the feasibility of in-situ synthesized TiC particles are confirmed. As the content of in-situ synthesized TiC particles increases, the hardness and wear resistance of the coatings are improved. In addition, the replacement of Cr in the in-situ reaction is considered to be beneficial for the corrosion resistance of the coating and reduces the sensitivity of intergranular corrosion. Two types of distinct corrosion mechanisms have been proposed.

Effect of Annealing on the Cavitation Erosion Resistance of HVOF-Sprayed Fe-Based Amorphous Composite Coatings

Effect of Annealing on the Cavitation Erosion Resistance of HVOF-Sprayed Fe-Based Amorphous Composite Coatings

Microstructure regulation and reinforcement mechanisms of ultrafine TiC/Fe55 composite coatings via laser melting deposition

The interfacial strength of phases are the main challenges that limit the service performance of metal matrix composites. In this paper, the influence mechanism of the ultrafine TiC particles introduced through both in-situ and external methods on the microstructure evolution, interfacial structure, phases distribution and wear resistance of Fe-based composite coatings by laser melting deposition were comprehensively investigated. It was found that the TiC particle in all prepared coatings was ultrafine scale with a pure interface. Particularly, the TiC particle added by the external method was presented as a composite structure in which the ex-situ TiC was wrapped with the in-situ TiC. For the in-situ method, as the (Ti + C) content increased (5–15 wt.%), the TiC particle changed from blocky to petal shape, and the wear volume was decreased and then increased. Compared with the adding of 10 wt.% nano-TiC externally, the coating with adding 10 wt.% (Ti + C) presented with greater wear resistant for its higher TiC content. The blocky TiC particles was beneficial to deflecting cracks and serving as wear-resistant skeletons due to the great interfacial bonding strength. This study provides a guidance for the preparation of high-performance Fe-based wear-resistant coatings for both newborn and remanufactured equipment parts.

Effects of heat treatment on microstructure and properties of Fe-based amorphous composite coatings

It is found that heat treatment can improve the microstructure and properties of the coating. In this paper, the Fe-Cr-Mo-B-C amorphous composite coatings fabricated by laser cladding technology were heat treated at different temperatures. The effects of heat treatment temperature on the crystallisation, porosity, microhardness, and corrosion resistance of coatings were investigated. The experimental results show that the amorphous content and porosity after heat treatment, the comprehensive properties are improved, and the coating defects are solved. Both the amorphous content and the porosity affect the corrosion resistance of the coatings. The smaller the porosity, the higher the amorphous content, and the stronger the corrosion resistance of the coating. When the difference in amorphous content is small, the porosity of the coating becomes the dominant factor affecting the corrosion resistance of the coating. The experimental results shows that the best optimum heat treatment temperature for the coatings is 200°C.

Microstructure and Corrosion Behavior of Fe-Based Austenite-Containing Composite Coatings Using Supersonic Plasma Spraying

The Fe-based austenite-containing composite coatings with various contents (3 vol.%, 6 vol.%, 9 vol.%, 12 vol.%) of austenite powder additions were created by supersonic plasma spraying on 45 steel substrates. The microstructure, phase composition, microhardness, and porosity of the composite coatings were examed. Moreover, special attention was paid to the effect of austenite powder on the corrosion resistance of the austenite-containing composite coatings. The results found that the addition of austenite powders could significantly improve the corrosion resistance of Fe-based coatings, which is mainly due to three correlated phenomena caused by the austenite particles. First, austenite particles significantly reduce the porosity of the austenite-containing composite coatings and form a denser coating structure due to their low melting point and good chemical compatibility with the Fe-based alloy. Further, austenite particles help to refine the grains and increase the grain boundary density. Last but not least, austenite particles help to generate more diffusely distributed second phases in the coating, improving the chemical homogeneity and hardness of the coating.

Tribological Properties of Laser-Cladded Fe-Based Amorphous Composite Coatings Under Dry and Lubricated Sliding

Tribological Properties of Laser-Cladded Fe-Based Amorphous Composite Coatings Under Dry and Lubricated Sliding