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.

Evaluation of Residual Stresses Within Plasma-Sprayed Zirconia (ZrO2-Y2O3 8%wt) Coatings

1998 ◽  
Author(s):  
N. Baradel ◽  
L. Bianchi ◽  
F. Blein ◽  
A. Freslon ◽  
M. Jeandin ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Thermal Spraying ◽  
Thermomechanical Properties ◽  
Hole Drilling ◽  
Stabilized Zirconia ◽  
Incremental Hole Drilling ◽  
Complementary Techniques ◽  
Plasma Sprayed ◽  
Steel Substrates

Abstract Thermal spraying induces stresses, which strongly influence thermomechanical properties of the deposits. To study both generation and influence of these stresses, various techniques could be used separately and/or concurrently. "In-situ" curvature, neutron diffraction and incremental hole drilling methods are often presented as complementary techniques. In this study, partially stabilized zirconia coatings, performed onto steel substrates at various spraying temperatures, have allowed to compare these three different methods.

Residual Stress Measurement of Plasma Sprayed Coating Layers in ZrO2

2007 ◽  
Vol 544-545 ◽  
pp. 451-454
Author(s):  
Soo Wohn Lee ◽  
Jia Zhang ◽  
Huang Chen ◽  
J. S. Song ◽  
Jae Kyo Seo ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Measurement ◽  
Diffraction Method ◽  
Spray Coating ◽  
X Ray Diffraction ◽  
Plasma Sprayed Coatings ◽  
Coating Layers ◽  
Sprayed Coating ◽  
Plasma Sprayed ◽  
Sprayed Coatings

Plasma sprayed coatings have been widely applied in modifying surface properties of metal components. It is also useful to prevent various types of wear, corrosion, erosion and thermal. But the residual stress is still an important problem which can effect the properties of sprayed coating. So it’s necessary to find out the reason of residual stress and the relationship between plasma sprayed condition and residual stress. Plasma spray coating layers with conventional ZrO2 powder was examined to calculate residual stress by X-ray diffraction method with various coating thickness.

Effect of Heat Treatment to Twin-Wire Arc Spraying Ni-5wt.%Al Coating on 6061-T6 Aluminum Alloy Diffusion

2013 ◽  
Vol 631-632 ◽  
pp. 424-428
Author(s):  
J.X. Wang ◽  
J.F. Sun ◽  
Z.P. Wang
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloy ◽  
Interface Reaction ◽  
Alloy Coating ◽  
Arc Spraying ◽  
Twin Wire Arc Spraying ◽  
Wire Arc Spraying ◽  
Al Coating ◽  
And Diffusion ◽  
Original Coating

In this study, Ni-5wt.%Al coating was fabricated on the 6061-T6 aluminum alloy substrate by twin-wire arc spraying technology. Through different heat treatment process, effect of microstructure and phase structure was studied with different temperature and time. Interface reaction mechanism of alloy coating/substrate and diffusion behavior of elements was discussed. Heat treatment was carried out at 400°C，480°C，550°C and respective for 4h, 24h, 48h. The XRD , SEM and EDS results showed that main phases of Ni-5wt.%Al original coating were composed of Ni solid solution, in addition to a small amount of Al2O3, NiO and Al4Ni3. Phase composition has basically not changed, interface of the coating/substrate occurred diffusion, which was controlled by the diffusion of Al atoms. Intermetallic compounds of NiAl3 and Ni2Al3 were formed in interface of coating/substrate, and interface diffusion area gradually was thickened.

scholarly journals Arc Spraying 3Cr13 Molten Drop Impact Stress Numerical Analysis

2013 ◽  
Vol 7 (1) ◽  
pp. 1-7
Author(s):  
C.H. Li ◽  
S. Wang ◽  
T.T. Zhao ◽  
Y.C. Ding
Keyword(s):  
Residual Stress ◽  
Theoretical Model ◽  
Thermal Spraying ◽  
Drop Impact ◽  
Arc Spraying ◽  
Coating Materials ◽  
Impact Stress ◽  
The Matrix ◽  
Change Temperature ◽  
Pressure Stress

In the thermal spraying process, the process for the molten metal particles to hit against matrix to form coating experiences great change temperature. Since the coating materials has different thermal physical properties with the matrix materials, the residual stress is surely left in the coating. Much bigger residual stress not only restricts coating thickness but also primarily affects coating binding strength. Having analyzed reason for residual stress in the thermal spraying coating and matrix, the theoretical model of arc spraying 3Cr13 molten drop impact stress is built and numerical simulation is done for this theoretical model. The result indicates that: the faster the molten drop speed is, the greater the pressure that matrix produces. When the molten drop's collision speed is 100m/s, it is not obvious for the matrix's pressure stress and when the collision speed is increased to 200m/s, the pressure stress produced in the matrix can maximize 5500Mpa; the faster the molten drop's collision speed is, the higher extent the molten drop's flattening is, which is more beneficial to increase coating’s bonding strength. The radius for the molten drop in the radius of 35μm becomes 80~110μm after collision and the flat ratio of the molten drop particle is about 3. The theoretical analysis is consistent with the experiment result.

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.

CFD Study of Particle and Compressible Flow Interaction for a Twin Wire Arc Spraying System

2019 ◽  
Author(s):  
Raymond Faull ◽  
Nicole Wagner ◽  
Kevin Anderson
Keyword(s):  
Plasma Spraying ◽  
Gas Flow ◽  
Particle Trajectory ◽  
Flow Direction ◽  
Phase Changes ◽  
Particle Flow ◽  
Spray Angle ◽  
Arc Spraying ◽  
Twin Wire Arc Spraying ◽  
Wire Arc Spraying

Abstract Plasma spraying is used in various industries for additive manufacturing applications to apply materials onto a workpiece. Such applications could be for the purpose of repair, protection against corrosion, wear-resistance, or enhancing surface properties. One plasma spraying method is the twin wire arc spraying (TWAS) process that utilizes two electrically conductive wires, across which an electric arc is generated at their meeting point. The molten droplets that are created are propelled by an atomizing gas towards a substrate on which the coating is deposited. The TWAS process offers low workpiece heating and high deposition rates at a lower cost compared to other plasma spraying techniques. As the spray angle for this technique is relatively large (15 degree half angle), particles are lost in the process, lowering the yield of deposited material. The motivation of this project was to constrict the particle flow and reduce the loss of particles that are ejected by the spraying torch. Torch nozzles were designed to help the particle trajectory match the axial flow direction of the atomizing gas flow. Simulations using ANSYS FLUENT Computational Fluid Dynamics (CFD) software was utilized to model both the atomizing gas flow and particle flow for a TWAS system. Various nozzle configurations with arc jet angles between 30–75 degrees showed only small effects on gas flow velocity and shape, with no significant variations in particle flow. These results indicate that nozzle configurations are only one factor in determining particle trajectory, and that phase changes and heat transfer need to be considered as well.

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