scholarly journals Monitoring and Optimisation of Ag Nanoparticle Spray-Coating on Textiles

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3165
Author(s):  
Sara Trabucco ◽  
Simona Ortelli ◽  
Benedetta Del Secco ◽  
Ilaria Zanoni ◽  
Franco Belosi ◽  
...  
Keyword(s):  
Spray Coating ◽  
Background Level ◽  
Deposition Efficiency ◽  
Far Field ◽  
Silver Deposition ◽  
Experimental Conditions ◽  
Dual Purpose ◽  
Spray Process ◽  
Worker Exposure ◽  
Spray System

An automatic lab-scaled spray-coating machine was used to deposit Ag nanoparticles (AgNPs) on textile to create antibacterial fabric. The spray process was monitored for the dual purpose of (1) optimizing the process by maximizing silver deposition and minimizing fluid waste, thereby reducing suspension consumption and (2) assessing AgNPs release. Monitoring measurements were carried out at two locations: inside and outside the spray chamber (far field). We calculated the deposition efficiency (E), finding it to be enhanced by increasing the spray pressure from 1 to 1.5 bar, but to be lowered when the number of operating sprays was increased, demonstrating the multiple spray system to be less efficient than a single spray. Far-field AgNPs emission showed a particle concentration increase of less than 10% as compared to the background level. This finding suggests that under our experimental conditions, our spray-coating process is not a critical source of worker exposure.

Dense Particulate Flow in a Cold Gas Dynamic Spray System

2007 ◽  
Author(s):  
B. Samareh ◽  
A. Dolatabadi
Keyword(s):  
Volume Fraction ◽  
Deposition Efficiency ◽  
Stagnation Pressure ◽  
Particulate Flow ◽  
Normal Velocity ◽  
Particle Interactions ◽  
Spray Process ◽  
Expansion Waves ◽  
Spray System ◽  
Compression And Expansion

The effect of particle-gas and particle-particle interactions in a cold spray process is studied when the particle loading is high. To examine the effect of the presence of a dense particulate flow on the supersonic gas, an Eulerian-Eulerian approach is used. It is found that when the volume fraction of the injected particles is increased, the turbulence of the gas phase will be augmented by the motion of particles and consequently, the shape, strength and location of the compression and expansion waves will be altered. Shock-particle interactions are demonstrated for various volume fractions. Another important parameter which will affect the spraying deposition efficiency is the substrate stand-off distance. It is found that the stagnation pressure alternates for different stand-off distances because of the formation of compression and expansion waves outside the nozzle exit. Particle normal velocity upon impact is a strong function of the stagnation pressure on the substrate as particles must pierce through the bow shock formed on that region. The substrate stand-off distance can be optimized to provide minimal pressure build-up on the substrate. This will result in a higher normal velocity upon impact and thus a higher deposition efficiency.

scholarly journals MATHEMATICAL MODELING OF PARTICLE IMPACT AND SOLIDIFICATION IN A THERMAL SPRAY PROCESS: PARTICLE ‐ SUBSTRATE INTERACTION

2000 ◽  
Vol 5 (1) ◽  
pp. 67-75
Author(s):  
G. Gromyko ◽  
G. Zayats ◽  
A. Sherbaf
Keyword(s):  
Stokes Equations ◽  
Droplet Diameter ◽  
Spray Coating ◽  
Processing Parameters ◽  
Heat Transfer Process ◽  
Navier Stokes ◽  
Liquid Particle ◽  
Navier Stokes Equations ◽  
Thermal Spray Process ◽  
Spray Process

In the present paper a mathematical model of creation plasma spray coating with the given properties is developed. The flattening and simultaneous solidification of a liquid particle upon its impingement onto a solid surface has been mathematically described and numerically simulated. Numerical simulation has been accomplished on the basis of the full Navier‐Stokes equations in cylindrical co‐ordinates. Heat transfer process in particle and substrate has been simulated by 2‐D problem heat conduction taking into account hydrodynamic processes into molten particle and forces of pressure. Particle solidification has been described by means of one‐dimensional Stefan problem. It was investigated the effects of some important processing parameters such as impact velocity, droplet diameter, pressure and temperature of plasma on the flattening and solidification of a single liquid particle. Calculations computational algorithm on the basis of finite‐difference method were created and a complex of applied programs was developed.

Thermal Spray for Corrosion Control: A Competitive Edge for Commercial Shipbuilding

1995 ◽  
Vol 11 (01) ◽  
pp. 53-55
Author(s):  
Frank S. Rogers
Keyword(s):  
Thermal Spray ◽  
Marine Environment ◽  
Thermal Spraying ◽  
Spray Coating ◽  
Cost Effective ◽  
Thermal Spray Coating ◽  
Coating System ◽  
Protection Mechanism ◽  
Arc Spray ◽  
Spray System

Thermal spraying of steel with aluminum to protect it from corrosion is a technology that has been proven to work in the marine environment. The thermal spray coating system includes a paint sealer that is applied over the thermally sprayed aluminum; this extends the service life of the coating, and provides color to the end product. The thermal spray system protects steel both through the principle of isolation (as in painting) and galvanization (as in galvanizing). With this dual protection mechanism, steel is protected from corrosion even when the coating is damaged. The thermal sprayed aluminum coating system has proven to be the most cost-effective corrosion protection system for the marine environment. Until recently, however, the initial cost of application has limited its use for general application. Today a new arc spray technology has reduced the application cost of thermal spraying aluminum to below that of painting. Commercial shipbuilders could use this technology to enhance their market position in the marine industry.

Investigation on Residual Stress Development During Multiple Impacts in Cold Spray Process

2019 ◽  
Author(s):  
Sagil James ◽  
Karan Shah
Keyword(s):  
Cold Spray ◽  
Particle Deposition ◽  
Md Simulation ◽  
Substrate Surface ◽  
Spray Coating ◽  
Layer By Layer ◽  
Original Material ◽  
Cold Spray Process ◽  
Spray Process ◽  
The Impact

Abstract The Cold Spray Process (CS) is a solid-state particle deposition process. Unlike thermal spray coating methods, the CS process does not involve melting of the particles and thus retains the desired original material properties along with oxide-free deposition. As the technology is of dynamic nature with high-velocity particle impacts, the bonding mechanism involved is hugely complicated to understand. Even though the CS process offers great benefits, its potential applications are restrained by a lack of knowledge of the complex operations involved. Preliminary research which used molecular dynamics (MD) simulation of the CS process revealed that factors including the angle of impact, size of particle and impact velocity significantly affect the material deposition. However, the preliminary study only considered a single particle impact during the coating process. The CS process involves the impact of multiple particles on the substrate surface depositing layer-by-layer. This research focuses on investigating the residual stresses distribution caused by the impact of multiple nanoparticles on the substrate surface during the CS process using MD simulation technique. The results obtained by this study are instrumental in further advancing the applications of the CS processes.

Microstructure and Wear Resistance of Laser Cladding of Ni-Based Alloy on Copper Substrate

2010 ◽  
Vol 663-665 ◽  
pp. 1061-1064 ◽  
Author(s):  
Yun Shan Wang ◽  
Neng Wen Liu ◽  
Fu Dong Zhu
Keyword(s):  
Wear Resistance ◽  
Laser Cladding ◽  
Copper Substrate ◽  
Spray Coating ◽  
Hardness Test ◽  
Spray Process ◽  
Plasma Spray Process ◽  
Coating Microstructure ◽  
Laser Remelt ◽  
Wear Tests

In order to improve the service life of copper crystallizer, a layer of Ni-based alloy on thick copperplate surface was performed by plasma spray process, and then YAG pulsed laser was used to remelt spray coating. Microstructure analysis, hardness test, and the wear resistance comparison experiments were taken to the specimen. The result shown that the Ni-based alloy cladding, metallurgy bonding with the copperplate, can be performed by taking the method of the YAG laser remelt technology; the structure of the cladding is compact, without defects such as pores and cracks. The micro hardness of cladding zone is between 450-490HV, which is much higher than that of the copper substrate (about 90 HV). The wear tests showed the laser cladding layer performed 14 times higher wear resistance compared to copper substrate.

An Alternative Thermal Spray Process to Plasma Spray in the Aircraft and Stationary Gas Turbine Industry

1994 ◽  
Author(s):  
Menno P. Zwetsloot ◽  
Elliott R. Sampson
Keyword(s):  
Thermal Spray ◽  
Plasma Spray ◽  
Nickel Aluminum ◽  
Thermal Spray Process ◽  
Spray Process ◽  
Arc Spray ◽  
Spray System ◽  
Technological Advances ◽  
Attachment Device ◽  
Plasma Sprayed

Technological advances in arc spray have produced an arc spray system that competes very favorably with other thermal spray processes. In the past arc spray was thought of as a process for very large parts that need thick buildups. However, an attachment device has been developed which focuses the pattern and accelerates the particles and is known as the Arc Jet system. The advantages of this device were discussed by Zwetloot, Sampson and Thorpe (1993), Reference 4. This attachment device coupled with the introduction of metal cored wires that provide the same chemistries as plasma sprayed powders, provides application engineers with a viable economic alternative to existing spray methods. A comparative evaluation of a standard production plasma spray system was conducted with the arc spray process utilizing the device mentioned above. This evaluation was conducted by an airline company on four major parts coated with nickel aluminum and results show that, for those applications, the arc spray process demonstrated significant benefit. It is expected that other applications may benefit from the use of the arc spray process as well.

The Study on High Temperature Stability Test of Ni/Cr Cold Spray Coating

2020 ◽  
Vol 901 ◽  
pp. 43-48
Author(s):  
Jirasak Tharajak ◽  
Noppakun Sanpo
Keyword(s):  
High Temperature ◽  
Cold Spray ◽  
Temperature Stability ◽  
Spray Coating ◽  
Deposition Efficiency ◽  
High Temperature Stability ◽  
Excellent Thermal Stability ◽  
Spray Coatings ◽  
Stability Performance ◽  
Cold Spray Coating

Recently cold spray coating technology was used for many applications in petrochemical business especially for high temperature required section. For this reason, the applied coating must be able to withstand at least 800 °C. The developed Ni/Cr cold spray coating was studied mainly on high temperature resistant property. Ni/Cr with the ratio of 80/20 feedstock powders revealed the highest deposition efficiency and it was selected to use as optimum feedstock powder compositions for the less of experimental study. Finally, it was found that Ni/Cr cold spray coatings reveal excellent thermal stability performance after completed both corrosion and thermal shock tests.

Tantalum Based High-Pressure Cold Spray Coatings on Stainless Steel Substrate

2019 ◽  
Vol 813 ◽  
pp. 429-434
Author(s):  
Jagannadh V.S.N. Sripada ◽  
Megil F. Gallant ◽  
Gobinda C. Saha ◽  
Reeti Singh ◽  
Jan Kondas
Keyword(s):  
High Pressure ◽  
Stainless Steel ◽  
Cold Spray ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
Transition Element ◽  
Spray Coating ◽  
Deposition Efficiency ◽  
High Heat ◽  
Inlet Temperature

Tantalum as a transition element possesses good corrosion resistant properties, along with ductility and hardness. It is also one of the best heat-resistant material (melting point 2996°C) and is known for its high heat and electrical conductivity. In this research, Tantalum is deposited on stainless steel substrate using high-pressure cold spray (HPCS) method. Cold spray coating technology enables the deposition of powder feedstock without melting. Feedstock particles are propelled through a nozzle at supersonic velocities and they deform plastically on impact, resulting in good bonding strength to the substrate. The low temperature and solid-state deposition associated with cold spray allows refractory materials such as Ta, Mo, and W to be deposited without high temperature requirements. The objective of this work is to achieve a dense and nonporous coating microstructure with a high deposition efficiency. The hardness of as-received tantalum particles is found to be 279 HV0.3 and the microstructure is very dense. Tensile testing carried on the sample coated at a stagnation gas pressure of 50 bar and gas inlet temperature of 900°C exhibited an ultimate tensile strength of 442 MPa and adhesion strength of 77 MPa. Further mechanical properties of the coating in terms of hardness is carried out by nanoindentation. These results will be correlated with microstructural imaging and elemental analysis including morphology and composition using scanning electron microscopy and X-ray diffraction techniques.

Cold Spray Processing of Titanium Powder

2000 ◽  
Author(s):  
J. Karthikeyan ◽  
C.M. Kay ◽  
J. Lindeman ◽  
R.S. Lima ◽  
C.C. Berndt
Keyword(s):  
Cold Spray ◽  
High Hardness ◽  
Deposition Efficiency ◽  
Hard Coatings ◽  
Nozzle Geometry ◽  
Maximum Effect ◽  
Vacuum Plasma Spray ◽  
Spray Process ◽  
Titanium Oxidation ◽  
Titanium Coatings

Abstract Oxygen-free titanium coatings are at present produced using vacuum plasma spray systems. The cold spray process can produce titanium coatings in atmospheric air at reduced cost. Variations of the deposition efficiency as well as the coating characteristics with various process parameters were studied. Results show that the deposition efficiency drops drastically below a critical temperature. The parameters which affect the jet velocity; viz., the type of gas and the nozzle geometry have maximum effect on the process deposition efficiency. Sprayed coatings were porous and exhibited a low modulus and high hardness. Post processing of the coating by machining produced dense, strong and hard coatings. Key words: Cold-Spray, Titanium, Oxidation.

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