scholarly journals Electroless Ni–P Plating on Mullite Powders and Study of the Mechanical Properties of Its Plasma-Sprayed Coating

Coatings ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 18
Author(s):  
Kaiwang Chen ◽  
Penglin Zhang ◽  
Pengfei Sun ◽  
Xianming Niu ◽  
Chunlian Hu
Keyword(s):  
Amorphous Layer ◽  
Cell Structures ◽  
Mullite Coating ◽  
Lower Porosity ◽  
Mullite Coatings ◽  
Sprayed Coating ◽  
Plasma Sprayed ◽  
Steel Substrates ◽  
Mullite Powder ◽  
Original Coating

To effectively improve the properties of a mullite coating and its interfacial bonding with the substrate, a Ni–P layer is deposited on the surface of mullite powders by electroless plating. The original mullite powders and coated mullite powders are then deposited onto stainless-steel substrates by plasma spraying. The growth mechanism of the Ni–P layer during the plating, the microstructures of the coated powders and mullite coating and the properties of the mullite coatings are characterized and analyzed. The results indicate that the Ni–P layer on the surface of the mullite powder has cell structures with a dense uniform distribution and grows in layers on the surface of the mullite powder. The crystallization behavior of Ni-P amorphous layer is induced by heat treatment. Compared to the original mullite coating, the coating prepared by the coated mullite powders has better manufacturability, stronger adhesion to the substrate, lower porosity (7.40%, 65% of that of the original coating), higher hardness (500.1 HV, 1.2 times that of the original coating), and better thermal cycle resistance (two times that of the original coating). The method of preparation of high-temperature thermal barrier coatings with coated mullite powders has a high application value.

New Set-Up to Measure Residual Stresses during Plasma Sprayed Coating Formation and Cooling

1996 ◽  
Author(s):  
A.C. Leger ◽  
A. Grimaud ◽  
P. Fauchais ◽  
C. Catteau
Keyword(s):  
Displacement Sensor ◽  
Alumina Coatings ◽  
Quenching Temperature ◽  
New Instrument ◽  
Coating Formation ◽  
Set Up ◽  
Sprayed Coating ◽  
Plasma Sprayed ◽  
Steel Substrates

Abstract A new instrument has been developed for measuring stresses due to particle quenching, temperature gradients during spraying, temperature fluctuations during coating formation and expansion mismatch between coating and substrate upon cooling. It records in situ and continuously the curvature of a substrate during spraying and upon cooling after spraying with a contacting displacement sensor. The substrate is fixed onto a pair of knife edges by springs. The knife edges are disposed on a water-cooled rotating cylindrical substrate holder and the substrate (2*15*100 mm3) is parallel to the holder axis. The torch is moved back and forth parallel to the holder axis and the substrate temperature is recorded by a thermocouple spot welded to it. Examples of results with alumina coatings on steel substrates are presented.

scholarly journals Porosity Analysis of Plasma Sprayed Coating by Application of Soft Computing

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Ajit Behera ◽  
S. C. Mishra ◽  
Asit Behera ◽  
J. P. Dhal
Keyword(s):  
Industrial Wastes ◽  
Low Grade ◽  
Ann Model ◽  
Generalization Capability ◽  
Wide Range ◽  
Artificial Neural Network Ann ◽  
Sprayed Coating ◽  
Porosity Analysis ◽  
Plasma Sprayed ◽  
Steel Substrates

The present piece of work describes the industrial wastes and low grade ores (fly ash + quartz + ilmenite, as the coating material), deposited on mild steel substrates. In many cases it is found that porosity is an important factor on the coating surface. Knowledge about the extent of these porosity imperfections is critical since they influence a wide range of spray coated properties and behaviors. To decrease the porosity by optimizing necessary operating parameters, artificial neural network (ANN) technique is used. The aim of this investigation is to find out appropriate input vectors in ANN model. ANN experimental results indicate that the projection network has good generalization capability to optimize the porosity.

scholarly journals Corrosion and Wear Resistance of Fe-Based Amorphous Coatings

Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 73 ◽  
Author(s):  
Guang Li ◽  
Youyi Gan ◽  
Chenheng Liu ◽  
Yu Shi ◽  
Yanchun Zhao ◽  
...  
Keyword(s):  
Plasma Spraying ◽  
Laser Cladding ◽  
Wear Behavior ◽  
Corrosion And Wear ◽  
Uniform Corrosion ◽  
Supersonic Plasma ◽  
Lower Porosity ◽  
Plasma Sprayed ◽  
Steel Substrates ◽  
Amorphous Coatings

Fe-based amorphous coatings were prepared on the surface of 45 steel substrates via supersonic plasma spraying and laser cladding. The corrosion and wear behavior of the two different coatings were investigated. Compared with supersonic plasma spraying, laser cladding resulted in coatings with a relatively denser structure, lower porosity, less cracks, and a good metallurgical bond with the substrate. Thanks to these properties, coatings produced by laser cladding exhibit a higher ability to resist uniform corrosion and better friction and wear performance than plasma-sprayed coatings.

Processing Effects on Residual Stress in Ni+5%AI Coatings–Comparison of Different Spraying Methods

2000 ◽  
Author(s):  
J. Matejicek ◽  
S. Sampath ◽  
T. Gnaeupel-Herold ◽  
H.J. Prask
Keyword(s):  
Residual Stress ◽  
Thermal Spraying ◽  
Stress Generation ◽  
Arc Spraying ◽  
Twin Wire Arc Spraying ◽  
Wire Arc Spraying ◽  
Generation Mechanisms ◽  
Sprayed Coating ◽  
Plasma Sprayed ◽  
Steel Substrates

Abstract Properties of thermally sprayed coatings, including residual stress, are controlled by various parameters of the spraying process. This study is focused on three thermal spraying techniques with significantly different particle temperatures and velocities. These are plasma spraying, twin wire arc spraying and high velocity oxy-fuel spraying. For each method, in-flight particle diagnostics was performed. Through-thickness residual stress profiles in Ni+5%A1 coatings on steel substrates were determined nondestructively by neutron diffraction. The stresses range from high tensile in the plasma sprayed coating to compressive in the HVOF one. Various stress generation mechanisms, including splat quenching, peening, and thermal mismatch, are discussed with respect to process parameters and material properties.

Effect of Oxidation on Sliding Wear Behavior of NiCrSiB-TiB2 Plasma Sprayed Coatings

2014 ◽  
Vol 604 ◽  
pp. 16-19 ◽  
Author(s):  
Oleksandr Umanskyi ◽  
Irina Hussainova ◽  
Maryna Storozhenko ◽  
Oleksandr Terentyev ◽  
Maksim Antonov
Keyword(s):  
Electron Spectroscopy ◽  
Auger Electron ◽  
Sliding Wear ◽  
Wear Behavior ◽  
Dry Sliding Wear ◽  
Plasma Sprayed Coatings ◽  
Sprayed Coating ◽  
Plasma Sprayed ◽  
Steel Substrates ◽  
Sprayed Coatings

The main goal of this work is to study dry sliding wear behavior of NiCrSiB-TiB2plasma sprayed coating against NiCrSiB coating. NiCrSiB-based powders with 10, 20, 40 wt.% TiB2particles content were deposited on steel substrates by plasma spraying. The structure of NiCrSiB-TiB2coatings consists of Ni-based matrix and TiB2and CrB grains. Among the coatings studied, the NiCrSiB-20wt.%TiB2shows excellent wear-resistance. The worn surfaces were observed using scanning electron microscopy and Auger electron spectroscopy to determine the wear mechanisms.

Laser Sintering of Nano-Al2O3 Powders on Plasma Sprayed Ceramic Based Coatings

2007 ◽  
Author(s):  
Lida Shen ◽  
Yinhui Huang ◽  
Zongjun Tian ◽  
Guoran Hua
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Plasma Spraying ◽  
Bond Coat ◽  
Continuous Wave ◽  
Ceramic Coatings ◽  
Laser Sintering ◽  
Al2o3 Ceramic ◽  
Plasma Sprayed ◽  
Steel Substrates

This paper describes an investigation of nano-Al2O3 powders reinforced ceramic coatings, which has included NiCrAl and Al2O3+13%wt.TiO2 coats pre-produced by atmosphere plasma spraying, implemented by laser sintering. Commercial NiCrAl powders were plasma sprayed onto 45 Steel substrates to give a bond coat with thickness of ∼100μm. The 600μm thick Al2O3+13%wt.TiO2 based coating was also plasma sprayed on top of the NiCrAl bond coat. With 2.5kw continuous wave CO2 laser, nano-Al2O3 ceramic powders were laser sintered on the based Coatings. The micro structure and chemical composition of the modified Al2O3+13%wt.TiO2 coatings were analyzed by such detection devices as scanning electronic microscope (SEM) and x-ray diffraction (XRD). Microhardness, wear resistance and corrosion resistance of the modified coatings were also tested and compared with that of the unmodified. The results show that the crystal grain size of Al2O3 had no obvious growth. In addition, due to the nanostructured Al2O3 ceramic phases, the coatings exhibited higher microhardness, better wear resistance and corrosion resistance than those unmodified counterparts. The complex process of plasma spraying with laser sintering as a potential effective way of the application of ceramic nano materials was also simply discussed and summarized in the end.

Investigations of the Fracture of Composites Matrix-Coating Under Tension

1998 ◽  
Author(s):  
V.E. Panin ◽  
V.A. Klimenov ◽  
S.V. Panin
Keyword(s):  
Steel Matrix ◽  
Matrix Composites ◽  
Coating Quality ◽  
Deformation Stages ◽  
The Matrix ◽  
Sprayed Coating ◽  
Plasma Sprayed

Abstract Deformation stages and specific features were studied by mesomechanical methods under tension of plasma sprayed coating-steel matrix composites. The effect of coating quality on the deformation of the matrix at the mesolevel was revealed. The results obtained make it possible to predict reliability and durability of this kind of coating and of the entire composite.

Microstructures and Characterization of Zirconia Coatings Formed by Laser Combined Plasma Spraying

1998 ◽  
Author(s):  
Z. Zhou ◽  
N. Eguchi ◽  
H. Shirasawa ◽  
A. Ohmori
Keyword(s):  
Laser Irradiation ◽  
Plasma Spraying ◽  
Barrier Properties ◽  
Thermal Barrier ◽  
Irradiation Treatment ◽  
Hybrid Plasma ◽  
Sprayed Coating ◽  
Steel Substrates ◽  
High Temperature Erosion

Abstract Hybrid plasma spraying combined with YAG laser irradiation was studied in order to obtain the optimum zirconia coatings for thermal barrier use. Zirconia coatings of approximately 150 ;Um in thickness were formed on the NiCrAlY under coated steel substrates both by means of conventional plasma spraying and hybrid plasma spraying under a variety of conditions. Post-laser irradiation was also conducted on the plasma as-sprayed coating for comparison. The microstructure of each coating was studied in detail and, for some representative coatings, thermal barrier properties were evaluated by hot erosion and a hot oxidation test. With hybrid spraying, performed under optimum conditions, it was found that a microstructure with appropriate partial densification and without connected porosities was formed and that cracks, which are generally produced in the post-laser irradiation treatment, were completely inhibited. In addition, hybrid spraying formed a smooth coating surface. These microstructural changes resulted in improved coating properties with regard to hardness, high temperature erosion resistance and oxidation resistance.

Sealing Treatment of Plasma Sprayed Cr3C2-NiCr/Al2O3-TiO2 Coating by Aluminum Phosphate Sealant Containing Al2O3 Nanoparticles

2021 ◽  
Author(s):  
Tuan Nguyen Van ◽  
Tuan Anh Nguyen ◽  
Ha Pham Thi ◽  
Ly Pham Thi ◽  
Phuong Nguyen ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Aluminum Phosphate ◽  
Al2o3 Nanoparticles ◽  
Treatment Efficiency ◽  
Typical Structure ◽  
Sprayed Coating ◽  
Plasma Sprayed ◽  
Sealing Treatment ◽  
Sprayed Coatings

Abstract A typical structure of thermal spray coatings consisted of molten particles, semi-molten particles, oxides, pores and cracks. These factors caused the porosity of sprayed coatings, leading to a great influence on the coating properties, especially their wear-corrosion resistance. In this study, a post-spray sealing treatment of Cr3C2-NiCr/Al2O3-TiO2 plasma sprayed coatings was carried out, then their corrosion properties were evaluated, before and after the treatment. For sealing process, aluminum phosphate (APP) containing aluminum oxide (Al2O3) nanoparticles (~10 nm) was used. The permeability of APP into the sprayed coating was analyzed by scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). The treatment efficiency for porosity and corrosion resistance of sprayed coatings were evaluated by electrochemical measurements, such as the potentiodynamic polarization and electrochemical impedance spectroscopy. In addition, the wear-corrosion resistance of the sealed coating was examined in 3.5 wt.% NaCl circulation solution containing 0.25 wt.% SiO2 particles. The obtained results showed that APP penetrated deeply through the sprayed coating. The incorporation of Al2O3 nanoparticles into APP sealant enhanced the treatment efficiency of porosity for sprayed coating. The effect of the post-treatment on corrosion protection of the sprayed coating has been discussed.

scholarly journals Comparison of Physical-chemical and Mechanical Properties of Chlorapatite and Hydroxyapatite Plasma Sprayed Coatings

2015 ◽  
Vol 9 (1) ◽  
pp. 42-55 ◽  
Author(s):  
Imane Demnati ◽  
David Grossin ◽  
Olivier Marsan ◽  
Ghislaine Bertrand ◽  
Gérard Collonges ◽  
...  
Keyword(s):  
Side Reaction ◽  
Processing Parameters ◽  
X Ray Diffraction ◽  
Unexpected Formation ◽  
Monoclinic Form ◽  
Ion Exchange Reaction ◽  
Physical Chemical ◽  
Distribution Mapping ◽  
Sprayed Coating ◽  
Plasma Sprayed

Chlorapatite can be considered a potential biomaterial for orthopaedic applications. Its use as plasma-sprayed coating could be of interest considering its thermal properties and particularly its ability to melt without decomposition unlike hydroxyapatite. Chlorapatite (ClA) was synthesized by a high-temperature ion exchange reaction starting from commercial stoichiometric hydroxyapatites (HA). The ClA powder showed similar characteristics as the original industrial HA powder, and was obtained in the monoclinic form. The HA and ClA powders were plasma-sprayed using a low-energy plasma spraying system with identical processing parameters. The coatings were characterized by physical-chemical methods, i.e. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy, including distribution mapping of the main phases detected such as amorphous calcium phosphate (ACP), oxyapatite (OA), and HA or ClA. The unexpected formation of oxyapatite in ClA coatings was assigned to a side reaction with contaminating oxygenated species (O2, H2O). ClA coatings exhibited characteristics different from HA, showing a lower content of oxyapatite and amorphous phase. Although their adhesion strength was found to be lower than that of HA coatings, their application could be an interesting alternative, offering, in particular, a larger range of spraying conditions without formation of massive impurities.

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