The cascaded-anode plasma torch makes it possible to get a longer and more stable plasma jet with higher specific enthalpy than conventional plasma torches. It is now used widely, but there are still few models of the cascaded-anode plasma torch. This study developed a 3-D time-dependent model that couples the gas phase and electrodes by encompassing the electromagnetic and heat equations both in the

A careful substrate preparation and the physical properties of the coating particles are decisive for the quality and envisaged properties of the deposited layer. Temperature, size, rate and velocity represent the classical quantities, which can be measured in situ using various diagnostics. Nonetheless, another quality-determining parameter is the degree of oxidation which could not be measured in

Sn-based Babbitt coatings are widely used for sliding in hydrodynamic bearings. The Babbitting of bearing surfaces is among others accomplished by casting; however, this implies some disadvantages such as segregations, or susceptibility to shrinkage defects. Thermal spraying represents a promising method to overcome these challenges. To date, no studies on Babbitt coatings deposited by means of low-pressure

The shear fatigue delamination strength of some porous thermal barrier coatings (TBCs) has been evaluated using the torsion pin-test method. The porosities of the tested TBCs were 0-5, 5-10, 15-20 and 25-35%. The shear delamination strength of the TBCs was evaluated and the shear fatigue delamination strength (S–N) curves were obtained under cyclic torsional loading. The Young’s modulus of the TBCs

High-entropy alloys (HEAs) are a new generation of materials that exhibit unique characteristics and properties, and are demonstrating potential in the form of thermal spray coatings for demanding environments. The use of HEAs as feedstock for coating processes has advanced due to reports of their exceptional properties in both bulk and coating forms. Emerging reports of thermal sprayed HEA coatings

Cold-spray additive manufacturing (CSAM) builds strong, dense metal parts from powder feedstock without melting and offers potential advantages over alternatives such as casting, liquid phase sintering, laser or e-beam melting or welding. Considerable effort is required to relieve residual stresses that arise from melt/freeze cycling in these methods. While CSAM does not involve melting, it imposes

Yttria-stabilized zirconia (YSZ) thermal barrier coatings (TBCs) were prepared by atmospheric plasma spraying (APS). SEM–EBSD–Raman spectroscopy evaluated the relationship between the crystallinity, stresses, and cracks in YSZ coatings. Cracks were more likely to form in locations having poor crystallinity, due to the tensile stresses. Analysis between the formation of cracks and stresses shows that

Cold spray has been developed recently to be used as an additive manufacturing technology in order to fabricate bulk components. Residual stresses are known to build up in coatings made by cold spray; therefore, cold spray additive manufacturing (CSAM) is also expected to generate residual stress in bulk parts and components, and that residual stress can lead to shape distortions or component cracking

In cold spray, high gas temperatures and high velocity impact of particles introduce complex thermal and stress histories in the coating layers and the substrate. It is crucial to understand the interplay between temperature evolution and residual stress development as the residual stresses could potentially cause distortion and/or delamination. In this study, a system-level cold-spray deposition model

High-velocity oxygen fuel coatings were produced using gas-atomized Al62.5Cu25Fe12.5 and Al67Cu20Fe5Cr8 powders onto a ferritic stainless-steel substrate, resulting in two similar microstructures, consisting mainly of quasicrystalline phases. The goal of this work was to evaluate the performance of the quasicrystalline coatings under standard wear and corrosion tests. The samples were characterized

Cavitation erosion is a huge problem in engineering structures working under hydrodynamic conditions. The synergistic effect of erosion and corrosion can aggravate the material removal by several orders of magnitude. Surface coatings are widely used to address material degradation by erosion–corrosion. However, non-homogenous microstructure and presence of defects leads to premature coating failure

Abstract Ternary energetic structural material (ESM) Ni–Al–CuO was prepared by cold spraying, and its mechanical properties studied under quasi-static-state and dynamic compression conditions. Energy release characteristics including the ignition temperature, energy release, and combustion wave velocity were characterized in both the thermal explosion and self-propagating combustion modes. The results

Suspension plasma spray (SPS) is going through a transition phase from research and development to daily use on production lines. Improving repeatability and reproducibility of coating elements and parameters makes SPS a replacement of former well-developed processes. This transition can be achieved by using in-flight particles diagnostic systems to monitor and control key parameters that influence

Gas turbine efficiency can be improved by increasing the operating temperature and by reducing the need for cooling air, both of which are enabled by higher temperature materials. Silicon carbide based ceramic matrix composites (CMCs) have shown promise for achieving higher temperatures. However, to survive in the high-temperature high-humidity combustion environment, environmental barrier coatings

Both tensile and shear adhesion strength tests were performed to evaluate interfacial strength between hydroxyapatite coatings on titanium alloy substrates subjected to anodization and heat treatment prior to deposition as well as post-deposition heat treatment. Results of the tensile adhesion strength tests were influenced by the size of the blasting media and the processing of pre- and post-heat

Thermal spray processes have been developing toward lower particle temperature and higher velocity. Latest generation high-velocity oxygen-fuel (HVOF) and high-velocity air-fuel (HVAF) can produce very dense coating structures due to the higher kinetic energy typical for these thermal spray processes. Thermally sprayed coatings usually contain residual stresses, which are formed by a superposition

High-velocity impact coatings are produced by techniques such as HVOF, HVAF, cold spraying, warm spraying, and supersonic plasma spraying. All these processes have in common the impact of particles at high velocities that produce peening of the surface and induce compressive residual stresses in the radial and axial orientations of the impact. If the process involves a significant heat input to the

In this study, the bonding formation of the cast iron splat deposited on a preheated aluminum substrate by atmospheric plasma spraying was investigated using a finite element method based on a heat transfer model built in a cylindrical coordinate system. To enhance the accuracy of calculations, thermal contact resistance (Rth) of the contact interface was incorporated into the calculation. A precise

In this study, Ti-6Al-4V (TC4) coating was prepared using an in situ shot peening-assisted cold spraying technology in which large shot peening particles were mixed with TC4 spraying powders to prepare the deposit. To improve its strength and toughness, the coating was heat-treated at 600-1000 °C in vacuum. The results demonstrated that the microstructure of the as-sprayed coating exhibited a special

In this work, TiC coating was fabricated by atmospheric plasma spray (APS) technique and its tribological performances sliding against stainless steel, Si3N4 and WC-Co were evaluated using ball-on-disk tests under 50 N load. The results indicated that the TiC coating exhibited diverse tribological behaviors. The TiC/Si3N4 tribopair showed the lowest friction coefficient with a significant fluctuation

Al2O3–ZrO2–Y2O3 composite coatings were prepared by plasma spraying Al2O3–ZrO2 composite powder with varying amounts of Y2O3. The effects of Y2O3 on the microstructure and properties of the plasma-sprayed Al2O3–ZrO2 composite coatings were investigated, and the results showed that the composition of the composite powder had a significant influence on the microstructure and properties of the Al2O3–ZrO2–Y2O3

Fe45Cr16Mo16C18B5 amorphous coatings were deposited on the mild steel substrate (0.45 wt.% C) by plasma spraying, and their corrosion resistance in 3.5 wt.% NaCl solution was compared with those of the substrate and 316 stainless steel. Potentiodynamic tests revealed that the as-prepared coatings had higher resistance to local corrosion than 316 stainless steel due to their wide passivation range.

Plasma spraying is now a standard coating process to deposit ceramic coatings for applications in automotive, aviation, medical and health care and others. This study deals with a hybrid thermal spray technique to deposit ceramic coatings. This technique named “hybrid-LVOF” (low-velocity oxyfuel) makes it possible to deposit uniform thin or thick ceramic coatings on metallic or ceramic substrates.

Fatigue behavior is strongly correlated with the residual stress state within thermal spray coatings, with neutral or compressive residual stresses being favorable for fatigue-sensitive applications. However, determination of the coating’s residual stress state is predominately made prior to subjection of the coating to cyclic loading and does not give insight into possible changes to the residual

Thermal barrier coatings (TBCs) are used to protect the hot sections of gas turbine and jet engines. A TBC system comprises of a substrate, bond coat (BC), and TBC top coat (TC). The residual stress development mechanism by high temperature exposure in TBC is important in designing a high-performance TBC. However, quantitative studies of the stress change and its modeling are few because of its difficulty

In the present study, microstructural analysis was carried out to investigate the effect of substrate surface chemistry on splat formation. Ni powder was sprayed onto stainless steel substrates exhibiting two different surface conditions (polished and oxidized) by high-velocity oxy-fuel (HVOF) thermal spray. X-ray photoelectron spectroscopy (XPS) was employed to investigate the chemical state of the

As a typical additive manufacturing technique, direct energy deposition is restricted from further application due to the presence of residual stress and the structural deformation. Thus, minimizing the residual stress plays a crucial role in additive manufacturing. In this work, a transverse static magnetic field is introduced in the laser remelting of Inconel 718 superalloy to investigate the effects

In cold spray additive manufacturing (CSAM), the severe plastic deformation of the input powder particles leads to an accumulation of residual stresses, the magnitude of which is affected by process conditions. In the current study, the effects of traverse speed and powder feed rate on the residual stress state were investigated in commercially pure titanium cylinders produced by CSAM. Residual stress

High demands for higher turbine efficiency bring attention to newer and more advanced insulating materials for the high temperature components in the turbine. Yttrium aluminum garnet (YAG) has shown good insulating properties in the previous published research, such as higher temperature limitation and better resistance to calcium–magnesium–alumina–silicate environmental contaminant penetration than

In-flight particle diagnostics have enhanced our understanding of thermal spraying and improved coating reproducibility. However, no methodology to verify the measured in-flight particle properties has been proposed in the literature yet. This methodology requires describing the entire free jet from accurate measured values. This study deals with a novel method to verify the measured in-flight particle

Eight-millimeter-thick high-strength AA2219 aluminum alloy plates were successfully welded by variable polarity tungsten inert gas welding, and the effect of cold spraying (CS) process on the residual stress, microstructure and mechanical properties of the welded joints were investigated. The CS experiment was performed under different driving gas temperatures and pressures and with different powder

The prevention of delamination of soft and ductile materials from hard substrates is a challenge when using the cold spray process. As a potential solution to this issue, a tunable hybrid additive manufacturing process was developed by coupling induction heating and cold spray processes. Pure aluminum was used as the soft feedstock powder, while Ti-6Al-4V was used for the hard substrate. The effects

Abstract The aim of this research was to establish whether the shell of green-lipped mussels and Pacific oysters could be plasma sprayed to promote and accelerate the establishment of filter feeder colonies. While CaCO3 degrades before melting under equilibrium conditions, the hypothesis considered in this work was that the high-temperature, highly nonequilibrium conditions experienced by powders during

Abstract Cavitation erosion is a major damage phenomenon in hydraulic turbine components that is caused by the bubble collapse. Protective coatings are widely applied as a form of surface modification to resist cavitation erosion. In this work, the WC and Cr3C2 cermet coatings were prepared by using HVOF, and their resistances to cavitation erosion in deionized water and 3.5 wt.% NaCl solution were

Abstract Amorphous alloys possess excellent mechanical properties such as high hardness and high wear resistance. CoCrFeNiBSi high-entropy alloys with amorphous phase have been prepared on the surface of H13 steel by utilizing various laser line energies. The microstructure, phase, hardness, and wear resistance of the cladding coatings were studied. The glass-forming ability of different cladding coatings

Abstract Cold spray is a promising process to coat polymers and carbon fiber-reinforced polymer (CFRP). The choice of the metal–polymer couple of materials, however, has a strong influence on coating buildup and properties. In the present work, we show that spraying mixtures of copper and polymer particles lead to composite coating. We observe that the polymer promotes coating buildup onto CFRP to

Abstract In plasma spraying, the particle velocity at the injector outlet has significant influence on the particles’ penetration into the plasma jet. The geometry of the injector and the flow rate of the carrier gas determine the particle velocities. Based on numerical simulations, it is evident that higher particle velocities and thus, a deeper penetration of the particles into the plasma jet, can

Abstract As the automotive industry shifts toward hybrid and alternative drive concepts like electromobility, it remains vital to continuously improve internal combustion technology. Internal combustion applications represent the largest portion of transportation technologies. Continuous development and improvement of passenger car engines focus on reducing emission by weight reduction and enhanced

Abstract In order to examine the effect of sliding speeds on the elevated temperature tribological performance of atmospheric plasma-sprayed Ni-Al-Ag-MoS2 (NAMB), Ni-Al-Ag-MoS2-5 wt.% hBN (NAMB5) and Ni-Al-Ag-MoS2-10 wt.% hBN (NAMB10) composite coatings, friction and wear tests were conducted against alumina ball as a counter face using ‘a rotary ball on disk configuration’ at a constant load of 5 N

Abstract Cu-Ni-Fe-coated and bare aluminum bronze materials are evaluated as O2-evolving anodes for Al production in low-temperature (700 °C) potassium-based cryolite. The Cu-Ni-Fe coating (~ 0.8 mm thick) is obtained by cold spraying of mechanically alloyed Cu65Ni20Fe15 (wt.%) powder and presents a biphase Cu-rich/Ni-Fe-rich structure. The composition and morphology of the scale formed on both anodes

Abstract Thermal cycling is able to cause interface undulation and interface delamination in the MCrAlY coating system. A generalized plane strain finite element model was built in this work to analyze interface undulation and interface delamination. Increasing thermally grown oxide (TGO) thickness facilitates interface undulation. The possible reason for this is that increase in TGO thickness causes

Abstract The cold spray (CS) process is unique due to its high strain rate deformation and particle deposition in solid state. In situ investigation of this process is challenging. Therefore, numerical methods have been used to simulate this process and provide a better ground for furthering the understanding of the process physics. Metallurgical bonding occurs during the deformation process at the

Abstract The good capacity of gray cast iron for the manufacture of complex geometry components is widely recognized, but its low resistance to corrosion and low weldability complicate the use of this material for some industrial applications. The corrosion resistance can be improved by metallic surface layers using welding processes with low percentages of dilution between the filler and base material

Abstract The present study aims to develop composite (amorphous + nanocrystalline) coating using blast furnace (BF) pig iron composition with the help of atmospheric plasma spray process for the first time. The usage of cheap and lean chemical composition of pig iron for the development of economical composite coating on mild steel substrate has led to the improvement in its hardness as well as corrosion

Abstract NiTi shape-memory alloy coatings were deposited by atmospheric plasma spray (APS) on mild-steel substrates and their mechanical properties such as hardness (Vickers’s microhardness), adhesion strength (ASTM C-633), and wear resistance (solid particle erosion) analyzed. The physical characteristics of the surface and interface of the as-deposited coating were investigated using scanning electron

Abstract In order to provide a basis for future optimization and control of the cold spray process, we experimentally studied the impact of various factors on the ductility (% elongation) of copper coatings. For the current application, cold-sprayed copper is employed as a corrosion barrier on carbon steel, while in addition to this, sufficient ductility is required for mechanical integrity. Results

Abstract The degradation of pump components by corrosion and complex, simultaneous damage mechanisms, e.g., erosion–corrosion and cavitation–corrosion leads to high costs through replacement and maintenance of parts. To increase the lifetime of cost-efficient components with superior casting properties, surface welding of duplex stainless steel on gray cast iron parts was performed using inert shielding

Abstract Ni-based alloys are resistant against wear and corrosion, and are widely applied in surface engineering. In this study, different amounts of graphite (0, 5 and 10 wt.%) are added to NiCrBSi powder as a solid lubricant. The pure and composite powders are deposited on 420 stainless steel through the high-velocity oxygen fuel process. The microstructure and properties of the coatings are examined

Abstract The hot corrosion resistance of air plasma-sprayed 8YSZ-Al2O3-multiwall carbon nanotubes (MWCNTs) has been analyzed and compared to that of 8YSZ coating. The feedstock constituents were blended to produce 8YSZ-20% alumina-0%MWCNT (type II), 8YSZ-19% alumina-1%MWCNT (type III), and 8YSZ-17% alumina-3%MWCNT (type IV) feedstock. After the cyclic hot corrosion (cHC) test in Na2SO4-60%V2O5 molten

Abstract Cold spray is a green additive manufacturing method that accelerates micron-size particles to supersonic speeds. At these high speeds, the particles deposit upon impact with a desired surface. High-density polyethylene, polyurethane, polyamide-12, polystyrene, and ultra-high molecular weight polyethylene particles were cold-sprayed onto a low-density polyethylene substrate under different