Effect of In-Flight Particle Characteristics on the Properties of Plasma Sprayed Nicraly & NiCoCrALY

1998 ◽  
Author(s):  
L. Pejryd ◽  
J. Wigren ◽  
P. Gougeon ◽  
C. Moreau
Keyword(s):  
Bond Coat ◽  
Dominant Role ◽  
Diagnostic System ◽  
Gas Flows ◽  
Spray Parameters ◽  
Particle Properties ◽  
Spraying Parameters ◽  
On Line ◽  
Coating Microstructure ◽  
Plasma Sprayed

Abstract Plasma sprayed bondcoats of MCrAIY type play a dominant role for the life of thermal barrier coatings. During service an oxide is formed between the bond and top coat, also internally and between the bond coat and the substrate. This oxide growth has to be minimised to improve the coating's life. Apart from the powder chemistry, the coating microstructure is the major factor governing the oxidation in a given environment. It is known that the coating microstructure and the coating strength are strongly related to the plasma spraying parameters. In this work, the effects of the in flight particle properties on the adhesion/cohesion and on the microstructure of a NiCrAIY & NiCoCrAIY bond coat are investigated. The relation between the particle velocity and temperature, as measured with the DPV 2000 particle diagnostic system, and the coating properties are very important. Relatively small changes of spray parameters (arc current, gas flows, ..) lead to significant changes on the sprayed particles and finally also in the coating microstructure. On the other hand, the same particle properties, although sprayed with different guns, produces coatings with similar properties. Through on-line control of the particle states it is expected that the quality of plasma sprayed MCrAIY's coatings can be significantly improved.

Investigation of the Long-Term Stability of Plasma Spraying by Monitoring Characteristics of the Sprayed Particles

1997 ◽  
Author(s):  
L. Leblanc ◽  
P. Gougeon ◽  
C. Moreau
Keyword(s):  
Plasma Spraying ◽  
Particle State ◽  
Electrode Wear ◽  
Spray Parameters ◽  
Long Term Stability ◽  
Long Term Experiment ◽  
On Line ◽  
Coating Microstructure ◽  
Plasma Sprayed

Abstract In plasma spraying temperature and velocity of the sprayed particles are among the most important parameters influencing the microstructure and properties of the deposited coatings. However, the sprayed particle state is influenced by uncontrollable parameters such as the wear state of the electrodes. In order to investigate the influence of the electrode wear state on sprayed particles, a long-term experiment was conducted during which on-line measurements of plasma sprayed yttria-zirconia powder were performed. Results show that even though input parameters were kept constant during the experiment the state of the sprayed particle changed significantly and coatings prepared at different spraying times have different microstructures and can have different properties. However, by changing some input spray parameters it was possible to retrieve the initial sprayed particle state and coating microstructure.

In-Flight Particle Characteristics of Plasma-Sprayed Dense Yttria Stabilized Zirconia

1998 ◽  
Author(s):  
L. Leblanc ◽  
C. Moreau
Keyword(s):  
Monitoring System ◽  
Particle Temperature ◽  
Deposition Efficiency ◽  
The State ◽  
Spray Parameters ◽  
Zirconia Powder ◽  
Integrated Optical ◽  
Coating Characteristics ◽  
Coating Microstructure ◽  
Plasma Sprayed

Abstract The influence of input spray parameters on the state of plasma-sprayed zirconia powder is studied. The particle temperature, velocity and diameter are measured using an integrated optical monitoring system. The monitoring system allows the investigation of the particles behavior in the spray jet. The collected information is correlated to coating characteristics such as deposition efficiency, microstructure and thermal diffusivity. Results show that, by monitoring the state of sprayed particles, a better understanding of the coating microstructure and properties can be achieved.

The Role of Different Atmospheric Plasma Spray Parameters on Microstructure of Abradable AlSi-Polyester Coatings

2017 ◽  
Vol 270 ◽  
pp. 224-229
Author(s):  
David Jech ◽  
Ladislav Čelko ◽  
Pavel Komarov ◽  
Jindřich Ziegelheim ◽  
Zdeněk Česánek ◽  
...  
Keyword(s):  
Deposition Efficiency ◽  
Atmospheric Plasma ◽  
Spray Parameters ◽  
Technological Parameters ◽  
Coating Microstructure ◽  
Two Parameters ◽  
Plasma Sprayed ◽  
Abradable Coatings ◽  
And Control

One of the approaches to increase the thermic efficiency of aerospace engines is the application of abradable coatings enabling minimization and control of the clearance between the stator and the rotating blades tips. The main purpose of this contribution is to define the role of different technological parameters utilized for atmospheric plasma spraying of AlSi-polyester coating on its resulting microstructure. Deposition of abradable coatings on the real engine parts is mostly dependent on spraying stand-off distance and on spraying angle. These two parameters influence not only the coating microstructure but also the deposition efficiency itself, which is directly connected with economical aspects of the coating production. The set of experimental samples with atmospheric plasma sprayed Ni-based bond coat and two in chemical composition same initial powders delivered from different powder manufacturers were used to spray thick AlSi-polymer top coats with different spraying stand-off distances and angles. Subsequently some of the samples were also heat treated to burn-out the polymer phase from the coating microstructure. The Rockwell HR15Y hardness was measured on all samples and the microstructure and coating thickness were evaluated by means of light microscopy and image analysis methods.

scholarly journals An Investigation of Particle Trajectories and Melting in an Air Plasma Sprayed Zirconia

1996 ◽  
Author(s):  
R.A. Neiser ◽  
T.J. Roemer
Keyword(s):  
Particle Surface ◽  
Spatial Separation ◽  
Air Plasma ◽  
Particle Size Distributions ◽  
Particle Properties ◽  
Density Distributions ◽  
Wide Range ◽  
Coating Microstructure ◽  
Plasma Sprayed ◽  
Zirconia Powders

Abstract The partially stabilized zirconia powders used to plasma spray thermal barrier coatings typically exhibit broad particle-size distributions. There are conflicting reports in the literature about the extent of injection-induced particle-sizing effects in air plasma-sprayed materials. If significant spatial separation of finer and coarser particles in the jet occurs, then one would expect it to play an important role in determining the microstructure and properties of deposits made from powders containing a wide range of particle sizes. This paper presents the results of a study in which a commercially available zirconia powder was fractionated into fine, medium, and coarse cuts and sprayed at the same torch conditions used for the ensemble powder. Diagnostic measurements of particle surface temperature, velocity, and number-density distributions in the plume for each size-cut and for the ensemble powder are reported. Deposits produced by traversing the torch back and forth to produce a raised bead were examined metallographically to study their shape and location with respect to the torch centerline and to look at their internal microstructure. The results show that, for the torch conditions used in this study, the fine, medium, and coarse size-cuts all followed the same mean trajectory. No measurable particle segregation effects were observed. Considerable differences in coating microstructure were observed. These differences can be explained by the different particle properties measured in the plume.

scholarly journals LOCAL MECHANICAL PROPERTIES OF ATMOSPHERIC SPRAYED MOLYBDENUM COATINGS DEPOSITED WITH CASCADED PLASMA TORCH

2020 ◽  
Vol 27 ◽  
pp. 32-36
Author(s):  
Jakub Antoš ◽  
Petra Šulcová ◽  
Kateřina Lencová ◽  
Šárka Houdková ◽  
Josef Duliškovic ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plasma Torch ◽  
Thermal Spraying ◽  
Atmospheric Plasma ◽  
Gas Flows ◽  
Mechanical And Tribological Properties ◽  
Spraying Parameters ◽  
Wide Range ◽  
Stable Plasma ◽  
Plasma Sprayed

Increasing interest for industrial use of thermally sprayed coatings leads to development in most thermal spraying technologies, including atmospheric plasma spraying (APS). The latest cascaded torch SinplexPro from Oerlikon Metco incorporates the efficiency advantages of cascaded arc technology into a single-cathode spray gun. It leads to more stable plasma arc across a wide range of gas flows, mixtures and pressures and also highly increases powder throughput. Thermal sprayed molybdenum coatings are widely used for improving wear resistance and sliding properties in many mechanical applications. Results of pure molybdenum coatings sprayed with cascaded plasma torch are not yet fully investigated. In this paper, mechanical properties of atmospheric plasma sprayed molybdenum coatings on steel (S235) substrate are evaluated. Optimization of spraying parameters for spherical Mo powder sprayed by cascaded plasma torch SinplexPro is carried out and the influence on final microstructure, mechanical and tribological properties of molybdenum coatings is analysed.

scholarly journals THE INFLUENCE OF THERMAL SPRAY PROCESS TECHNOLOGICAL PARAMETERS ON THE PROPERTIES OF COATINGS / TERMINIO PURŠKIMO TECHNOLOGINIŲ PARAMETRŲ POVEIKIS DANGŲ SAVYBĖMS

2017 ◽  
Vol 8 (6) ◽  
pp. 592-595
Author(s):  
Aleksandr Lebedev ◽  
Olegas Černašėjus ◽  
Jelena Škamat
Keyword(s):  
Aluminum Alloy ◽  
Influence Of Spray Parameters ◽  
Spray Parameters ◽  
Technological Parameters ◽  
Properties Of Coatings ◽  
Thermal Spray Process ◽  
Spray Process ◽  
Coating Microstructure ◽  
Pre Treatment ◽  
Plasma Sprayed

The article deals with the plasma sprayed Ni-based coating on aluminum alloy substrates. Before spraying, the surfaces of substrates were modified employing sandblasting and its combination with preheating. The coatings were sprayed under variation of spray process parameters. The study involves coating microstructure, porosity and adhesion tests. The influence of spray parameters and substrate pre-treatment on the properties of coating were evaluated. Straipsnyje nagrinėjamos plazminio purškimo būdu ant aliuminio lydinio substrato užpurkštos Ni pagrindo dangos. Substrato paviršius prieš purškimą buvo apdorotas smėliavimo būdu, taip pat ir pakaitinant substratą iki 150 °C temperatūros. Naudojant skirtingus plazminio purškimo proceso parametrus, buvo užpurkštos nikelio-aliuminio dangos. Darbe ištirta gautų dangų mikrostruktūra, akytumas ir adhezijos stipris. Įvertintas plazminio purškimo parametrų ir substrato paruošimo poveikis gautų dangų savybėms.

scholarly journals Determining Interface Fracture Toughness in Multi Layered Environmental Barrier Coatings with Laser Textured Silicon Bond Coat

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 55
Author(s):  
Markus Wolf ◽  
Hideki Kakisawa ◽  
Fabia Süß ◽  
Daniel Emil Mack ◽  
Robert Vaßen
Keyword(s):  
Bond Coat ◽  
Ceramic Matrix Composites ◽  
Interface Fracture ◽  
Matrix Composites ◽  
Air Plasma ◽  
Cohesive Failure ◽  
Corrosive Media ◽  
Environmental Barrier ◽  
Interface Toughness ◽  
Plasma Sprayed

In the high temperature combustion atmosphere inside of aircraft turbines, the currently used ceramic matrix composites require a protective environmental barrier coating (EBC) to mitigate corrosion of the turbine parts. Besides thermomechanical and thermochemical properties like matching thermal expansion coefficient (CTE) and a high resistance against corrosive media, mechanical properties like a high adhesion strength are also necessary for a long lifetime of the EBC. In the present work, the adhesion between an air plasma sprayed silicon bond coat and a vacuum plasma sprayed ytterbium disilicate topcoat was aimed to be enhanced by a laser surface structuring of the Si bond coat. An increase in interface toughness was assumed, since the introduction of structures would lead to an increased mechanical interlocking at the rougher bond coat interface. The interface toughness was measured by a new testing method, which allows the testing of specific interfaces. The results demonstrate a clear increase of the toughness from an original bond coat/topcoat interface (8.6 J/m2) compared to a laser structured interface (14.7 J/m2). Observations in the crack propagation indicates that the laser structuring may have led to a strengthening of the upper bond coat area by sintering. Furthermore, in addition to cohesive failure components, adhesive components can also be observed, which could have influenced the determined toughness.

scholarly journals Influence of Different Annealing Atmospheres on the Mechanical Properties of Freestanding MCrAlY Bond Coats Investigated by Micro-Tensile Creep Tests

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 692 ◽  
Author(s):  
Sven Giese ◽  
Steffen Neumeier ◽  
Jan Bergholz ◽  
Dmitry Naumenko ◽  
Willem J. Quadakkers ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Creep Strength ◽  
Bond Coat ◽  
Oxide Dispersion Strengthened ◽  
Tensile Creep ◽  
Creep Tests ◽  
Bond Coats ◽  
Nial Phase ◽  
Lower Strain ◽  
Plasma Sprayed

The mechanical properties of low-pressure plasma sprayed (LPPS) MCrAlY (M = Ni, Co) bond coats, Amdry 386, Amdry 9954 and oxide dispersion strengthened (ODS) Amdry 9954 (named Amdry 9954 + ODS) were investigated after annealing in three atmospheres: Ar–O2, Ar–H2O, and Ar–H2–H2O. Freestanding bond coats were investigated to avoid any influence from the substrate. Miniaturized cylindrical tensile specimens were produced by a special grinding process and then tested in a thermomechanical analyzer (TMA) within a temperature range of 900–950 °C. Grain size and phase fraction of all bond coats were investigated by EBSD before testing and no difference in microstructure was revealed due to annealing in various atmospheres. The influence of annealing in different atmospheres on the creep strength was not very pronounced for the Co-based bond coats Amdry 9954 and Amdry 9954 + ODS in the tested conditions. The ODS bond coats revealed significantly higher creep strength but a lower strain to failure than the ODS-free Amdry 9954. The Ni-based bond coat Amdry 386 showed higher creep strength than Amdry 9954 due to the higher fraction of the β-NiAl phase. Additionally, its creep properties at 900 °C were much more affected by annealing in different atmospheres. The bond coat Amdry 386 annealed in an Ar–H2O atmosphere showed a significantly lower creep rate than the bond coat annealed in Ar–O2 and Ar–H2–H2O atmospheres.

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