scholarly journals Preparation and Performance Optimization of Original Aluminum Ash Coating Based on Plasma Spraying

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 770 ◽  
Author(s):  
Hongjun Ni ◽  
Jiaqiao Zhang ◽  
Shuaishuai Lv ◽  
Xingxing Wang ◽  
Yu Zhu ◽  
...  
Keyword(s):  
Plasma Spraying ◽  
Plasma Spray ◽  
Performance Optimization ◽  
Gas Flow ◽  
Orthogonal Experiment ◽  
Angle Of Repose ◽  
Spray Parameters ◽  
Coating Properties ◽  
Industrial Solid Waste ◽  
And Performance

As an industrial solid waste, the original aluminum ash (OAA) will cause serious pollution to the air and soil. How to reuse the OAA has been a research difficulty. Thus, a method of preparing a plasma spray powder using OAA is proposed. The OAA was hydrolyzed and ball milled, and the flowability of original aluminum ash spray powder (OAASP) was evaluated by the angle of repose. The coating properties were determined via analyzing the microstructure and the phase of the coating, and the effects of plasma spray parameters on the coating properties were investigated by the orthogonal experiment to optimize spray parameters. The results show that the angle of repose of OAASP after granulation was less than 40°, which met the requirements of plasma spraying. When the spraying current was 600 A, the spraying voltage was 60 V, the main gas flow was 33 slpm, and the powder flow rate was 22 g/min, and the prepared original aluminum ash coating (OAAC) had excellent comprehensive performance. After the spraying process parameters were optimized, the microhardness of the coating was 606.54 HV, which is about twice the hardness of the substrate; the abrasion rate was 12.86 × 10−3 g/min; the porosity was 0.16%; and the adhesive strength was 16 MPa. When the amount of Al2O3 added was 50%, the hardness of the coating was increased by 17.61%.

Plasma Spraying of Solid Oxide Fuel Cell Components

1997 ◽  
Author(s):  
G. Schiller ◽  
M. Müller ◽  
R. Ruckdäschel ◽  
R. Henne ◽  
M. Lang
Keyword(s):  
Plasma Spraying ◽  
Plasma Spray ◽  
Solid Oxide ◽  
Rf Plasma ◽  
Spray Parameters ◽  
Oxide Fuel ◽  
Bipolar Plates ◽  
Metallic Bipolar Plates ◽  
Protective Layers ◽  
Near Net Shape

Abstract The central components for solid oxide fuel cells (SOFC) are the electrodes-electrolyte multilayer arrangement (PEN) and the separating bipolar plates. The PEN (Positive electrode- Electrolyte-Negative electrode) assembly consists of a dense gastight yttria-stabilized zirconia (YSZ) electrolyte and porous electrodes for which usually Ni-YSZ cermet anode and Sr-doped LaMnO3 cathode layers are used. The various PEN units are connected in a cell stack by bipolar plates which are either metallic or ceramic ones. Furthermore, a protective layer on the metallic bipolar plates consisting of a chromium alloy is required to prevent chromium evaporation leading to a rapid and strong degradation of the SOFC performance. At the DLR Stuttgart both the DC and the RF vacuum plasma spraying technique have been further developed and adapted to meet the requirements for the manufacture of the different SOFC components. The DCVPS process using specially developed Laval-like nozzles is especially appropriate to the production of thin and dense coatings as required for the electrolyte and the protective layers. However, applying special spray parameters and nozzles it is also possible to deposit porous electrode layers. The production of the entire PEN arrangement in one consecutive DC-VPS process is the objective of the actual development. On the other hand, the RF plasma spray technique is suitable for the near net-shape production of bulk components such as the metallic bipolar plate. The development of the deposition processes for the production of SOFC components using DC and RF plasma spray methods and the results obtained concerning PEN fabrication, deposition of protective layers and the near net-shape production of metallic bipolar plates are presented in the paper.

Process Maps for Plasma Spray Part I: Plasma-Particle Interactions

2000 ◽  
Author(s):  
D.L. Gilmore ◽  
R.A. Neiser ◽  
Y. Wan ◽  
S. Sampath
Keyword(s):  
Plasma Spray ◽  
Gas Flow ◽  
Operating Conditions ◽  
Injection Velocity ◽  
Microstructural Development ◽  
Spray Parameters ◽  
Particle Interactions ◽  
Plasma Particle ◽  
Particle Injection ◽  
Process Maps

Abstract This is the first paper of a two part series based on an integrated study carried out at Sandia National Laboratories and the State University of New York at Stony Brook. The aim of the study is to develop a more fundamental understanding of plasma-particle interactions, droplet-substrate interactions, deposit formation dynamics and microstructural development as well as final deposit properties. The purpose is to create models that can be used to link processing to performance. Process maps have been developed for air plasma spray of molybdenum. Experimental work was done to investigate the importance of such spray parameters as gun current, auxiliary gas flow, and powder carrier gas flow. In-flight particle diameters, temperatures, and velocities were measured in various areas of the spray plume. Samples were produced for analysis of microstructures and properties. An empirical model was developed, relating the input parameters to the in-flight particle characteristics. Multi-dimensional numerical simulations of the plasma gas flow field and in-flight particles under different operating conditions were also performed. In addition to the parameters which were experimentally investigated, the effect of particle injection velocity was also considered. The simulation results were found to be in good general agreement with the experimental data.

scholarly journals Study on Preparation of Aluminum Ash Coating Based on Plasma Spray

2019 ◽  
Vol 9 (23) ◽  
pp. 4980 ◽  
Author(s):  
Lv ◽  
Zhang ◽  
Ni ◽  
Wang ◽  
Zhu ◽  
...  
Keyword(s):  
Plasma Spray ◽  
Orthogonal Experiment ◽  
Raw Material ◽  
Atmospheric Plasma ◽  
Angle Of Repose ◽  
Powder Flow ◽  
Comprehensive Performance ◽  
Abrasion Rate ◽  
Powder Flow Rate ◽  
Water Hydrolysis

Ultimate aluminum ash (UAA) was used as the key raw material to prepare ultimate spray powder (USP) via water hydrolysis and ball milling, after which the coating was prepared by atmospheric plasma spray. The flowability of the USP was evaluated by the angle of repose; the process parameters of the coating were determined by orthogonal experiment, and the microstructure and properties of the coating were characterized. The results show that the ultimate spray powder after granulation has an angle of repose less than 40°, which meets the requirements of plasma spray. When the spray current is 600 A, the spray voltage is 55 V, the powder flow rate is 22 g/min, and the main air flow is 33 lspm, the prepared ultimate coating has the best comprehensive performance. The microhardness of the coating is 512 HV, which is about 1.5 times the hardness of the substrate; the abrasion rate is 18.53 × 10–3 g/min; the porosity is 0.17% and the average adhesive strength is 8.78 Mpa, which confirms the feasibility of using aluminum ash as a spray powder to prepare a coating.

Mix Ratio Design and Performance Optimization of Vitrified Microsphere Insulating Mortar

2012 ◽  
Vol 476-478 ◽  
pp. 1639-1642
Author(s):  
Jin Ping Chen
Keyword(s):  
Performance Optimization ◽  
Raw Materials ◽  
Orthogonal Experiment ◽  
Polypropylene Fiber ◽  
Physical And Mechanical Properties ◽  
Dry Density ◽  
Building Insulation ◽  
Composition Materials ◽  
New Type ◽  
And Performance

Vitrified microsphere insulation mortar is a new type building insulation mortar which developed in recent years, with having the advantages of well workability, high intensity and fire prevention. But because the vitrified microsphere we use of which much exists on the defects of high dry density and bad insulation effect, it analyzed deeply kinds of factors which influence on the physical and mechanical properties of vitrified microsphere insulation mortar, making use of orthogonal experiment to optimize the composition materials of insulation mortar. The orthogonal test results show that the most influential raw materials factors to mortar insulation properties and 28d compressive strength followed by aggregate, polypropylene fiber, fly ash and latex powder.

Effect of Spray Parameters on the Plasma in High Pressure Plasma Spraying Up to 300 kPa

1998 ◽  
Author(s):  
S. Sodeoka ◽  
M. Suzuki ◽  
T. Inoue ◽  
K. Ueno
Keyword(s):  
High Pressure ◽  
Plasma Spraying ◽  
Gas Flow ◽  
High Plasma ◽  
Chamber Pressure ◽  
Spray Parameters ◽  
Electric Voltage ◽  
Flow Rates ◽  
Pressure Plasma ◽  
Spraying Parameters

Abstract To develop the spraying parameters for effective and safe operation of high pressure plasma spraying, the influence of nozzle bore diameter and plasma gas flow on the characteristics of plasma torch have been investigated under the chamber pressure ranging from 5 to 300 kPa. Large bore size allows high plasma gas flow rates without excessive increasing electric voltage, which is apt to damage the cathode. High flow rates (Ar: 1.3x10-3, H2: 1.3x10-4, He: 2.7x10-4 m3/s) is effective in imbuing more power into the plasma without nozzle damage under higher chamber pressures. The relationships among the parameters, such as the effective plasma power, the electric efficiency, the chamber pressure, the plasma gas flow and so on, were expressed qualitatively by a multiple regression analysis.

Microstructure and Abrasive Wear Properties of Plasma Sprayed Nanostructured Al2O3-TiO2-ZrO2-CeO2 Coatings

2011 ◽  
Vol 291-294 ◽  
pp. 117-124
Author(s):  
Wei Qin Wu ◽  
Qiang Li ◽  
Zhen Yi Wei ◽  
Hui Ye
Keyword(s):  
Bond Strength ◽  
Plasma Spraying ◽  
Plasma Spray ◽  
Normal Load ◽  
Liquid Phase Sintering ◽  
Orthogonal Experimental Design ◽  
Spray Parameters ◽  
Wear Properties ◽  
Spalling Fracture ◽  
Plasma Sprayed

Al2O3-TiO2-ZrO2-CeO2 coatings formed via a plasma spray approach. The optimal spray parameters of plasma sprayed nano-structured coating were determined by orthogonal experimental design, based on porosity, bond strength of the coatings and the partly melted(PM) zone percentage. Microstructure of the plasma sprayed nanostructured Al2O3-TiO2-ZrO2-CeO2 coating sprayed on the optimal spray parameters was analyzed. Wear map was established by wear experiments. The results show, nanostructured coating contains fully melted (FM) zone and PM zone, the increasing of the critical plasma spray parameter (CPSP) promote the decreasing of the PM zone percentage and the increasing of the bond strength of the coatings. The composition phases of the powder reacted to each other during the plasma spraying process. FM and PM zone resulted from fully melted droplets and partly melted particles respectively. Nanosized crystals and amorphous particles exist in the PM zone, liquid phase sintering is taken place in the PM zone. The main wear mechanism of plasma spraying coatings are plastic deformation and microplow, microfracture and grain spalling, fracture and delamination at different normal load and sliding speed in dry friction.

scholarly journals Diagnostics for advanced materials processing by plasma spraying

2005 ◽  
Vol 77 (2) ◽  
pp. 443-462 ◽  
Author(s):  
C. Moreau ◽  
J.-F. Bisson ◽  
R. S. Lima ◽  
B. R. Marple
Keyword(s):  
Substrate Temperature ◽  
Plasma Spraying ◽  
Operating Conditions ◽  
Diagnostic Tools ◽  
Spray Parameters ◽  
Production Environment ◽  
Coating Properties ◽  
Industrial Sectors ◽  
Plasma Sprayed ◽  
Jet Characteristics

Advanced coatings deposited by plasma spraying are used in a large variety of industrial applications. The sprayed coatings are employed typically in industry to protect parts from severe operating conditions or to produce surfaces with specific functions. Applications are found in many industrial sectors such as aerospace, automobile, energy generation, and biomedical implants.Coatings are built by the successive deposition of molten or partially molten particles that flatten and solidify upon contact on the substrate, forming lamellae. The coating properties are intimately linked to the properties of these lamellae, which in turn depend on in-flight particle properties as well as substrate temperature during spraying. Consequently, the development of diagnostic tools for monitoring and controlling these spray parameters will help provide the necessary information to study the coating formation process, optimize the coating properties, and, eventually, control the spray process in production.In this paper, a review of some recent developments of optical diagnostic techniques applied to monitor plasma-sprayed particles is presented. In the first part of the paper, two different sensing techniques for in-flight particle measurement are described. First, time-resolved diagnostics on individual particles is described. This technique is used to study the instabilities of the particle characteristics associated with the plasma fluctuations. Secondly, a technique adapted for use in an industrial production environment for measuring the particle jet characteristics as an ensemble is presented. In the second part of the paper, the use of an optical system to study the influence of the substrate temperature on the flattening and solidification of sprayed particles impacting on a flat substrate is described. The last part of this paper describes the optimization of nanostructured coatings based on a tight control of the temperature and velocity of the plasma-sprayed particles.

Thermal Spraying of Silicon Nitride - Based Powders

1996 ◽  
Author(s):  
S. Thiel ◽  
R.B. Heimann ◽  
M. Herrmann ◽  
L.-M. Berger ◽  
M. Nebelung ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Phase Transformations ◽  
Plasma Spraying ◽  
Plasma Spray ◽  
Thermal Spraying ◽  
Spray Parameters ◽  
Cohesion Strength ◽  
Statistical Variation ◽  
Low Pressure Plasma ◽  
Low Pressure Plasma Spraying

Abstract Thermal spraying of silicon nitride has been considered impossible because the high temperatures involved lead inevitably to decomposition/oxidation of the material. To address these issues, improved silicon nitride-based powders were developed, two of which have been tested as reported in this paper. The powders were applied using low pressure plasma spraying (LPPS) and the resulting coatings characterized based on microhardness, adhesion, and cohesion strength. Phase transformations of the powders during spraying were also investigated and preliminary optimization strategies by statistical variation of plasma spray parameters were tested.

Reactive Plasma Spraying of 80:20 Ni/Cr and Mcraly Powders with Hydrocarbon Reactive Gases

1998 ◽  
Author(s):  
O. Al-Sabouni ◽  
D.J. Stephenson ◽  
J.R. Nicholls ◽  
G. Creffield
Keyword(s):  
Plasma Spraying ◽  
Oxygen Content ◽  
Graphite Tube ◽  
Spray Parameters ◽  
Plasma Flame ◽  
Reactive Plasma Spraying ◽  
Reactive Plasma ◽  
Order Of Magnitude ◽  
Hydrocarbon Gas ◽  
And Performance

Abstract Reactive Plasma Spraying (RPS) with a hydrocarbon gas has been studied as a method to improve the mechanical properties of a commercially available 80:20 Ni/Cr alloy and subsequently as a method to reduce the oxygen content of MCrA1Y coatings. A conventional d.c. plasma torch has been modified by attaching a conical graphite tube (reactor) onto the end of the gun. The powder is then sprayed through the reactor with injected reactive hydrocarbon gas. The reactor shrouds the plasma flame from the external atmosphere and contains the desirable inner atmosphere necessary for RPS. When using a reactor and reactive gas the plasma environment is changed significantly, making it necessary to alter the spraying parameters from those recommended by the manufacturer for a particular powder. Work has been carried out to establish the effect various spray parameters have on the final coating such that new parameters can be selected which maximise the coatings quality and performance. Significant improvements have been achieved in terms of both objectives with hardnesses being doubled for the 80/20 Ni/Cr alloy and an order of magnitude reduction in the oxygen content for the MCrA1Y alloy.

Optimization of the Atmospheric Plasma Spray Parameters using Design of Experiments for Coatings on AISI 410 Stainless Steel

2016 ◽  
Vol 1812 ◽  
pp. 53-64
Author(s):  
E. Bautista Pérez ◽  
C.E. Cruz ◽  
Juan M. Salgado Lopez ◽  
J.A. Toscano
Keyword(s):  
Design Of Experiments ◽  
Factorial Design ◽  
Plasma Spray ◽  
Gas Flow ◽  
Empirical Relationship ◽  
Atmospheric Plasma Spray ◽  
Atmospheric Plasma ◽  
Spray Parameters ◽  
Process Variables ◽  
Wear Protection

ABSTRACTIn this work, the effect of three principal and independent parameters of Atmospheric Plasma Spray on the properties of coatings deposited using mixtures of commercial powders of titanium dioxide (TiO2) and chromium oxide (Cr2O3) was studied. The results of this work are used for special applications on turbomachinery components such as wear protection in sliding seals and in steam valves for turbines, chemical protection for centrifugal compressor members, and special seal applications.The design of experiments (DoE) technique has proved to be very useful to study the influence factors and optimization. Pierlot et al. [1] demonstrated that the application of the Hadamard and two factorial design techniques are useful for the optimization of thermal spray processes. An example of the application of the DoE is the one mentioned by Murugan et al. [2]. In their work, a factorial design was used to study the interactions between gas flow, oxygen flow, powder rate and spray distance on the percentage of porosity and hardness of TiO2 - Cr2O3 composite coatings generated by High Velocity Oxy-Fuel.The ½ fractional two-level factorial DoE technique was used to analyze and optimize the Atmospheric Plasma Spray process parameters. In the current research, experiments were conducted varying the deposition velocity, gas flow and stand-off distance. The effect of these process variables were evaluated by thickness, hardness and microstructure analysis. In this study, an empirical relationship between process variables and response parameters was developed. The entire relationship was made using the results of the DoE.

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