Electrolytic Co-Deposition Mechanisms, Texture Layers, and Residual Stresses in Nanocomposite Coatings Processes: A Review

The composite coating has gained wider attention due to its property to protect materials used in energy, bridges, offshore platforms, underground pipelines, and the aviation industry from corrosion and deterioration. In this work, a literature review was conducted about the processes of nanocomposite coating, the mechanisms of electrolytic co-deposition, the texture of layers, and the residual stresses. An important aspect, residual stress, was emphasized, which represents the persistent stress after removing the external force affecting a metal in the plastic region. Because it cannot be measured directly and may be determined by measuring strain and indirect methods, the sources and methods for measuring residual stresses (XRD, SEM, TEM, EDS) were described in the last section to provide a comprehensive overview. Based on the thorough analysis of the published literature, it was concluded that nanoparticles could be electrodeposited with Ni on an Al substrate using a direct current and Ni sulfamate as an electrolytic solution, and Nickel will not reside on the oxide layer covering Al, so chemical changes are needed to prepare the Al surface. In addition, texture changes with the thickness of the coated layer must be investigated.

Spray pyrolysis feasibility of tungsten substitution for cobalt in nickel-rich cathode materials

Cobalt(Co)serves as a stabilizer in the lattice structure of high-capacity nickel(Ni)-rich cathode materials.However,its high cost and toxicity still limit its development.In general,it is possible to perform transition metal substitution to reduce the Co content.However,the traditional coprecipitation method cannot satisfy the requirements of multielement coprecipitation and uniform distribution of elements due to the differences between element concentration and deposition rate.In this work,spray pyrolysis was used to prepare LiNi_(0.9)Co_(0.1-x)W_(x)O_(2)(LNCW).In this regard,the pyrolysis behavior of ammonium metatungstate was analyzed,together with the substitu-tion of W for Co.With the possibility of spray pyrolysis,the Ni-Co-W-containing oxide precursor presents a homogeneous distribution of metal elements,which is beneficial for the uniform substitution of W in the final materials.It was observed that with W substitution,the size of primary particles decreased from 338.06 to 71.76 nm,and cation disordering was as low as 3.34%.As a consequence,the pre-pared LNCW exhibited significantly improved electrochemical performance.Under optimal conditions,the lithium-ion battery assembled with LiNi_(0.9)Co_(0.0925)W_(0.0075)O_(2)(LNCW-0.75mol%)had an improved capacity retention of 82.7%after 200 cycles,which provides insight in-to the development of Ni-rich low-Co materials.This work presents that W can compensate for the loss caused by Co deficiency to a cer-tain extent.

HVOF-sprayed HAp/S53P4 BG composite coatings on an AZ31 alloy for potential applications in temporary implants

Bioactive thermal spray coatings produced via high-velocity oxygen fuel spray(HVOF)from hydroxyapatite(HAp)and bioactive glasses(BG)have the potential to be employed on temporary implants due to the ability of both HAp and BG to dissolve and promote osseointegration,considering that both phases have different reaction and dissolution rates under in-vitro conditions.In the present work,75%wt.HAp-25%wt.S53P4 bioactive glass powders were HVOF-sprayed to obtain HAp/S53P4 BG composite coatings on a bioresorbable AZ31 alloy.The study is focused on exploring the effect of the stand-off distance and fuel/oxygen ratio variation as HVOF parameters to obtain stable structural coatings and to establish their effect on the phases and microstructure produced in those coatings.Different characterization techniques,such as scanning electron microscopy,X-ray diffraction,and Fourier transform infrared spectroscopy,were employed to characterize relevant structural and microstructural properties of the composite coatings.The results showed that thermal gradients during coating deposition must be managed to avoid delamination due to the high temperature achieved(max 550℃)and the differences in coefficients of thermal expansion.It was also found that both spraying distance and oxygen/fuel ratio allowed to keep the hydroxyapatite as the main phase in the coatings.In addition,in-vitro electrochemical studies were performed on the obtained HAp/S53P4 BG composite coatings and compared against the uncoated AZ31 alloy.The results showed a significant decrease in hydrogen evolution(at least 98%)when the bioactive coating was applied on the Mg alloy during evaluation in simulated body fluid(SBF).

Experimental investigation on effective aerosol scavenging using different spray configurations with pre-injection of water mist for Fukushima Daiichi decommissioning

During the decommissioning of the Fukushima Daiichi nuclear power plant,it is important to consider the retrieval of resolidified debris both in air and underwater configurations.For the subsequent retrieval of debris from the reactor building,the resolidified debris must be cut into smaller pieces using various cutting methods.During the cutting process,aerosol particles are expected to be generated at the submicron scale.It has been noted that such aerosols sizing within the Greenfield gap(0.1-1μm)are difficult to remove effectively using traditional spraying methods.Therefore,to improve the aerosol removal efficiency of the spray system,a new aerosol agglomeration method was recently proposed,which involves injecting water mist to enlarge the sizes of the aerosol particles before removing them using water sprays.In this study,a series of experiments were performed to clarify the proper spray configurations for effective aerosol scavenging and to improve the performance of the water mist.The experimental results showed that the spray flow rate and droplet characteristics are important factors for the aerosol-scavenging efficiency and performance of the water mist.The results obtained from this study will be helpful for the optimization of the spray system design for effective aerosol scavenging during the decommissioning of the Fukushima Daiichi plant.

Simulation Study on the Heat Transfer Characteristics of a Spray-Cooled Single-Pipe Cooling Tower

The current study focuses on spray cooling applied to the heat exchange components of a cooling tower.An optimization of such processes is attempted by assessing different spray flow rates and droplet sizes.For simplicity,the heat exchanger of the cooling tower is modeled as a horizontal round tube and a cooling tower spray cooling model is developed accordingly using a computational fluid dynamics(CFD)software.The study examines the influence of varying spray flow rates and droplet sizes on the heat flow intensity between the liquid layer on the surface of the cylindrical tube and the surrounding air,taking into account the number of nozzles.It is observed that on increasing the spray flow strength,the heat flow intensity and extent of the liquid film in the system are enhanced accordingly.Moreover,the magnitude of droplet size significantly impacts heat transfer.A larger droplet size decreases evaporation in the air and enhances the deposition of droplets on the round tube.This facilitates the creation of the liquid film and enhances the passage of heat between the liquid film and air.Increasing the number of nozzles,while maintaining a constant spray flow rate,results in a decrease in the flow rate of each individual nozzle.This decrease is not favorable in terms of heat transfer.

Investigation of the Film Formation in Dynamic Air Spray Painting

To accurately predict the film thickness distribution during dynamic spraying performed with air guns and support accordingly the development of intelligent spray painting,the spray problem was analyzed numerically.In particular,the Eulerian-Eulerian approach was employed to calculate the paint atomization and film deposition process.Different spray heights,spray angles,spray gun movement speeds,spray trajectory curvature radii,and air pressure values were considered.Numerical simulation results indicate that the angle of spray painting significantly affects the velocity of droplets near the spray surface.With an increase in the spraying angle,spraying height and spray gun movement speed,the maximum film thickness decreases to varying degrees,and the uniformity of the film thickness also continuously worsens.When the spray gun moves along an arc trajectory,at smaller arc radii,the film thickness on the inside of the arc is slightly greater than that on the outside,but the impact on the maximum film thickness is minimal.Increasing air pressure expands the coating coverage area,results in finer atomization of paint droplets,and leads to a thinner and a more uniform paint film.However,if the pressure is too high,it can cause paint splattering.Using the orthogonal experimental method,multiple sets of simulation calculations were conducted,and the combined effects of spraying height,spray angle,and spray gun movement speed on the film thickness distribution were comprehensively analyzed to determine optimal configurations.Finally,the reliability of the numerical simulations was validated through dynamic spray painting experiments.

Effects of plasma spraying process on microstructure and mechanical properties of Cr_(2)AlC/410 composite coatings

To investigate the influences of Cr_(2)AlC mass fraction and supersonic plasma spraying process on the microstructure and mechanical properties of Cr_(2)AlC reinforced 410 stainless steel composite coatings,the coatings containing different mass fractions of Cr_(2)AlC were prepared and investigated.The composite coating exhibited low porosity and high adhesion strength.The addition of Cr_(2)AlC significantly enhanced the hardness of the composite coatings through particle strengthening.However,when the mass fraction of Cr_(2)AlC was 20%,the aggregation of Cr_(2)AlC resulted in a strong decrease in the coating preparation efficiency,as well as a decline in adhesion strength.In the supersonic plasma spraying process,the Ar flow rate mainly influenced the flight velocity of the particles,while the H_(2) flow rate and the current mainly affected the temperature of the plasma torch.Consequently,all of them influenced the melting degree of particles and the quality of the coating.The lowest porosity and the highest hardness and adhesion strength could be obtained when the Ar flow rate is 125 L/min,the H_(2) flow rate is 25 L/min,and the current is 385 A.

Effect of cold rolling deformation on microstructure evolution and mechanical properties of spray formed Al−Zn−Mg−Cu−Cr alloys

The impact of cold rolling deformation,which was introduced after solid solution and before aging treatment,on microstructure evolution and mechanical properties of the as-extruded spray formed Al−9.8Zn−2.3Mg−1.73Cu−0.13Cr(wt.%)alloy,was investigated.SEM,TEM,and EBSD were used to analyze the microstructures,and tensile tests were conducted to assess mechanical properties.The results indicate that the D1-T6 sample,subjected to 25%cold rolling deformation,exhibits finer grains(3.35μm)compared to the D0-T6 sample(grain size of 4.23μm)without cold rolling.Cold rolling refines the grains that grow in solution treatment.Due to the combined effects of finer and more dispersed precipitates,higher dislocation density and smaller grains,the yield strength and ultimate tensile strength of the D1-T6 sample can reach 663 and 737 MPa,respectively.In comparison to the as-extruded and D0-T6 samples,the yield strength of the D1-T6 sample increases by 415 and 92 MPa,respectively.

Preparation and Properties of Spray Polyurea Elastomer for Aquaculture Foam Floating Balls

[Objectives] This study was conducted to develop a polyurea elastomer which can be sprayed on the surface of expanded polystyrene (EPS) floating balls, so as to improve the surface strength and service life of the floating balls. [Methods] The effects of the types and amounts of isocyanate, chain extenders and polyether polyols on the gelation rate, adhesion and wear resistance of polyurea elastomer were investigated, and it was finally determined the preparation process of polyurea elastomer using liquid isophorone diisocyanate (IPDI) and amino-terminated polyether (D2000) as the main raw materials, dimethylthiotoluene diamine (E300) as the chain extender and silica as the wear resistance modifier through two-step solution polymerization of prepolymerization and chain extension. [Results] The physical properties and chemical resistance tests of spray polyurea elastomer showed that it had good physical properties and acid and alkali resistance, and could meet the requirements of spraying and protection of EPS floating ball surface in marine environment. [Conclusions] Polyurea elastomer coating can improve the aging resistance, wear resistance and acid and alkali resistance of EPS floating balls, and prevent them from being fragile and floating randomly to form marine floating garbage which results in "white pollution".

Effect of Spray Rails on Takeoff Performance of Amphibian Aircraft

Amphibian aircraft have seen a rise in popularity in the recreational and utility sectors due to their ability to take off and land on both land and water, thus serving a myriad of purposes, such as aerobatics, surveillance, and firefighting. Such seaplanes must be aerodynamically and hydrodynamically efficient, particularly during the takeoff phase. Naval architects have long employed innovative techniques to optimize the performance of marine vessels, including incorporating spray rails on hulls. This research paper is dedicated to a comprehensive investigation into the potential utilization of spray rails to enhance the takeoff performance of amphibian aircraft. Several spray rail configurations obtained from naval research were simulated on a bare Seamax M22 amphibian hull to observe an approximate 10% - 25% decrease in water resistance at high speeds alongside a 3% reduction in the takeoff time. This study serves as a motivation to improve the design of the reference airplane hull and a platform for detailed investigations in the future to improve modern amphibian design.

Designing an Experimental Device for Swinging Excitation Spray Cooling

In this paper,we introduce the design principle of the oscillating excited spray cooling experimental device.We then designed an oscillating excited spray cooling experimental device.By using the device,the swaying motion can be realized through the control system,and the motion of the droplet under different vibration frequencies can be observed.By measuring the liquid flow rate and pressure,the changes in liquid flow rate,pressure,and temperature with time under different vibration frequencies were studied.The trajectory of the droplet and the temperature distribution of the droplet under different vibration frequencies could be observed.The device has a simple structure,is easy to control,and can achieve continuous observation of the spray cooling process.

Microstructure and high temperature oxidation resistance of Si-Y co-deposition coatings prepared on TiAl alloy by pack cementation process

In order to improve the high temperature oxidation resistance of TiAl alloy, Y modified silicide coatings were prepared by pack cementation process at 1030, 1080 and 1130 °C, respectively, for 5 h. The microstructures, phase constitutions and oxidation behavior of these coatings were studied. The results show that the coating prepared by co-depositing Si?Y at 1080 °C for 5 h has a multiple layer structure: a superficial zone consisting of Al-rich (Ti,Nb)5Si4 and (Ti,Nb)5Si3, an out layer consisting of (Ti,Nb)Si2, a middle layer consisting of (Ti,Nb)5Si4 and (Ti,Nb)5Si3, and aγ-TiAl inner layer. Co-deposition temperature imposes strong influences on the coating structure. The coating prepared by Si?Y co-depositing at 1080 °C for 5 h shows relatively good oxidation resistance at 1000 °C in air, and the oxidation rate constant of the coating is about two orders of magnitude lower than that of the bare TiAl alloy.

Experimental study on the microstructural and anti-corrosion behaviour of Co-deposition Ni-Co-SiO_2 composite coating on mild steel

Mild steel is commonly used in the construction of Pipeline. The major problem of this Pipeline is corrosion. Effort is make my researchers to combat this problem. In this work Co-deposition of Ni-CoSiO_2 composite coating on mild steel was reported with the view to reduce this problem. The SiO_2 was varies from 5 to 25 wt% in the deposition. The microstructure, hardness values and potentiodynamic polarization in simulated sea water were determined. The results show that XRD pattern of the Ni Co deposited mild steel revealed the presence hard phases of NiO, Co_5Ni, Co_2Ni_3, Ni Co5 while that of Ni-CoSiO_2 deposited mild steel revealed the presence harder phases of NiOSiO_2, CoNi_7Si_2, Co_5Ni_2Si_3. The NiCo-25 SiO_2 deposited sample has smaller particle size than Ni-10 Co coating. Coating thickness of 110.7 mm was obtained for Ni-10 Co coating, while coating thickness of 135.7, 157.7, 165.0 mm were obtained at Ni-10 Co-x SiO_2(x=10, 15, 25 wt%). 99.90% corrosion resistance was achieved at Ni-Co-25 SiO_2. This improvement in corrosion resistance after composites coating could be attributed to the hard and fine structure obtained after coating.

Si-Al-Y Co-deposition Coatings Prepared on Ti-Al Alloy for Enhanced High Temperature Oxidation Resistance

Si-Al-Y co-deposition coatings were prepared on Ti-Al alloy by pack cementation processes at 1 050 ℃ for 4 h with different halide activators in the packs for enhancing the high temperature oxidation resistance of Ti-Al alloy. The structure, constituent phases, formation process and oxidation behavior of the coatings were investigated. The experimental results showed that the coatings prepared respectively with NaF and NH_4Cl as activators were composed of a（Ti, X）_5Si_4,（Ti, X）_5Si_3（X represents Nb and Cr）, and TiSi_2 outer layer, a TiAl_2 inner layer and an Al-rich interdiffusion zone. However, the constituent phases changed into TiSi_2 in the outer layer and（Ti, X）_5Si_4 and（Ti, X）_5Si_3 phases were observed in the middle layer of the coating prepared with AlCl_3·6H_2O activator. Among the halide activators studied, the coating prepared with AlCl_3·6H_2O was thicker and denser, which is the only suitable activator for pack Si-Al-Y co-deposition coatings on a Ti-Al alloy. The oxidation results show that the coating can protect the Ti-Al alloy from oxidation at 1000 ℃ in air for at least 80 h. The excellent oxidation resistance of the coating is attributed to the formation of a dense scale mainly consisted of TiO_2, SiO_2 and Al_2O_3.

Effects of submicron diamonds on the growth of copper in Cu-diamond co-deposition

Submicron diamonds were co-deposited on aluminum substrates with copper from the acid copper sulfate electrolyte by electro- lyte-suspension co-deposition. After submicron diamonds were added to the electrolyte, the shape of copper grains transformed from oval or round to polyhedron, the growth mode of copper grains transformed from columnar growth to gradual change in size, and the preferred ori- entation of copper grains transformed from （220） to （200）. Analyzing the variation of cathodic overpotential, it was found that the cathodic overpotential tended to remain tmchanged when copper plane （220） grew in the process of electrodepositing pure copper, while it tended to decrease with time when copper plane （200） grew in the process of co-deposition. It was inferred that copper plane （200） was propitious to the deposition of submicron diamonds.

Ti+C+N FILM PREPARATION AND ITS PROPERTIES BY LOW ENERGY CO-DEPOSITION ON STEEL

The Ti+C+N film was co-deposited on H13 steel by Filtered Vacuum Arc PlasmaDeposition (FVAPD) operated with a modified cathode. The co-deposited layer was effective for theimprovement of surface hardness and corrosion resistance. The nano-hardness value of theco-deposited film is 1.3 times more than that of undeposited sample. The corrosion behaviormeasurement shows that the corrosion resistance for acid corrosion and pitting corrosion wasimproved greatly. It is owing to the formation of the new ternary ceramic phase TiC_(0.7) N_(0.3) inthe co-deposited layer. The mechanism of property improvement is discussed.

Ferronickel preparation using Ni-Fe co-deposition process

Nucleation mechanism and technological process for Ni-Fe co-deposition with a relatively high Fe^(2+)concentration surrounded were described,and the effects of Fe^(2+) concentration,solution pH,temperature,and sodium dodecyl sulfonate concentration were investigated.Electrochemical experiments demonstrate that iron's electrodeposition plays a leading role in the Ni-Fe co-deposition process,and the co-deposition nucleation mechanism accords with a progressive nucleation.Temperature increase does favor in increasing nickel content in the ferronickel(Ni-Fe co-deposition products),while Fe^(2+) concentration increase does not.When solution pH is higher than 3.5,nickel content in the ferronickel decreases with pH because of the hydrolysis of Fe^(2+).With the current density of 180 A/m^2,Na_2SO_4 concentration of 100 g/L and Ni^(2+) concentration of 60 g/L,a smooth ferronickel deposit containing 96.21% Ni can be obtained under the conditions of temperature of 60 °C,Fe^(2+) concentration of 0.3 g/L,solution pH of 3 and sodium dodecyl sulfonate concentration of 40 mg/L.

Influence of Spray Gun Position and Orientation on Liquid Film Development along a Cylindrical Surface

A method combining computationalfluid dynamics(CFD)and an analytical approach is proposed to develop a prediction model for the variable thickness of the spray-induced liquidfilm along the surface of a cylindrical workpiece.The numerical method relies on an Eulerian-Eulerian technique.Different cylinder diameters and positions and inclinations of the spray gun are considered and useful correlations for the thickness of the liquidfilm and its distribution are determined using various datafitting algorithms.Finally,the reliability of the pro-posed method is verified by means of experimental tests where the robot posture is changed.The provided cor-relation are intended to support the optimization of spray-based coating applications.

Growth behaviors and emission properties of Co-deposited MAPbI_(3) ultrathin films on MoS_(2)

Hybrid organic–inorganic perovskite thin films have attracted much attention in optoelectronic and information fields because of their intriguing properties. Due to quantum confinement effects, ultrathin films in nm scale usually show special properties. Here, we report on the growth of methylammonium lead iodide(MAPbI_(3)) ultrathin films via co-deposition of PbI_2 and CH_3NH_3I(MAI) on chemical-vapor-deposition-grown monolayer MoS_(2) as well as the corresponding photoluminescence(PL) properties at different growing stages. Atomic force microscopy and scanning electron microscopy measurements reveal the MoS_(2) tuned growth of MAPbI_(3) in a Stranski–Krastanov mode. PL and Kelvin probe force microscopy results confirm that MAPbI_(3) /MoS_(2) heterostructures have a type-Ⅱ energy level alignment at the interface. Temperaturedependent PL measurements on layered MAPbI_(3) (at the initial stage) and on MAPbI_(3) crystals in averaged size of 500 nm(at the later stage) show rather different temperature dependence as well as the phase transitions from tetragonal to orthorhombic at 120 and 150 K, respectively. Our findings are useful in fabricating MAPbI_(3) /transition-metal dichalcogenide based innovative devices for wider optoelectronic applications.

The Influence of Sea Sprays on Drag Coefficient at High Wind Speed

Field and laboratory observations indicate that the variation of drag coefficient with wind speed at high winds is different from that under low-to-moderate winds.By taking the effects of wave development and sea spray into account,a new parameterization of drag coefficient applicable from low to extreme winds is proposed.It is shown that,under low-to-moderate wind conditions so that the sea spray effects could be neglected,the nondimensional aerodynamic roughness first increases and then decreases with the increasing wave age;whereas under high wind conditions,the drag coefficient decreases with the increasing wind speed due to the modification of the logarithmic wind profile by the effect of sea spray droplets produced by bursting bubbles or wind tearing breaking wave crests.The drag coefficients and sea surface aerodynamic roughnesses reach their maximum values vary under different wave developments.Correspondingly,the reduction of drag coefficient under high winds reduces the increasing rate of friction velocity with increasing wind speed.