Microstructural and Mechanical Characterization of Mechanically-Activated Plasma-Sprayed Nanostructured Al2O3-TiO2 and Al2O3-ZrO2 Coatings

2006 ◽  
Vol 45 ◽  
pp. 1224-1229
Author(s):  
Sandrine Coste ◽  
Ghislaine Bertrand ◽  
Christian Coddet ◽  
Eric Gaffet ◽  
Horst Hahn ◽  
...  
Keyword(s):  
Plasma Spraying ◽  
Gas Flow ◽  
Structural Changes ◽  
Mechanical Characterization ◽  
Raw Materials ◽  
Phase Changes ◽  
Atmospheric Plasma ◽  
Plasma Sprayed ◽  
Zirconia Powders

Granulated nanostructured alumina/titania and alumina/zirconia powders were used to achieve coatings by atmospheric plasma spraying. Raw materials and mechanically activated ceramic mixtures (alumina with 13wt% and 44wt% of titania or 40wt% and 80wt% of zirconia) have been considered to produce the sprayable powders. Effects of various plasma spray conditions (primary Ar and secondary H2 gas flow rates, arc intensity) on the microstructure, phase content and microhardness of the coatings have been evaluated. It has been shown by SEM observations that the coatings exhibit a lamellar structure consisting in fully melted and partially melted areas including porosity, ranging from 10 to 30vol.%. The phase changes (from αAl2O3 to γAl2O3, from anatase to rutile for TiO2, Al2TiO5) or structural changes that occur during the plasma spraying of the nanostructured powders were investigated by XRD and related to the processing conditions and in turn to the amount of unmelted powder.

scholarly journals Microstructure and Wear Behaviors of Plasma-Sprayed MoAlB Ceramic Coating

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 474
Author(s):  
Fuzhu Li ◽  
Shengnan Sun ◽  
Yong Xu ◽  
Lihui Tian ◽  
Yun Wang ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Plasma Spraying ◽  
Ceramic Coating ◽  
Adhesive Wear ◽  
Ceramic Coatings ◽  
Atmospheric Plasma ◽  
Wear Rates ◽  
Arc Power ◽  
Plasma Sprayed

MoAlB ceramic coatings were prepared on a 316 steel surface by atmospheric plasma spraying with different arc power levels. The phase composition, microstructure and wear resistance of coatings against GCr15 and Si3N4 counterparts were studied. The MoAlB ceramic decomposed and was oxidized to form MoB and Al2O3 during plasma spraying. With the increase of the arc power, MoAlB experienced more decomposition, but the coatings became denser. When the arc power increased from 30 to 36 kW, the wear rates of coatings against GCr15 and Si3N4 balls reduced by 91% and 78%, respectively. The characterization of wear tracks shows that when against GCr15 counterparts, the main wear mechanisms are abrasive and adhesive wear, and when against Si3N4 counterparts, fatigue and abrasive wear are dominant. The refinement of wear resistance by increasing arc power can be attributed to the improvement of density and adhesive strength among splats.

scholarly journals Wear Behavior Analysis of Al2O3 Coatings Manufactured by APS and HVOF Spraying Processes Using Powder and Suspension Feedstocks

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 879
Author(s):  
Monika Michalak ◽  
Paweł Sokołowski ◽  
Mirosław Szala ◽  
Mariusz Walczak ◽  
Leszek Łatka ◽  
...  
Keyword(s):  
Plasma Spraying ◽  
Wear Behavior ◽  
Ceramic Coatings ◽  
Suspension Plasma Spraying ◽  
Atmospheric Plasma ◽  
Hvof Spraying ◽  
The Coefficient Of Friction ◽  
Wear Mode ◽  
Α Al2o3 ◽  
Plasma Sprayed

Thermally sprayed ceramic coatings are applied for the protection of surfaces that are exposed mainly to wear, high temperatures, and corrosion. In recent years, great interest has been garnered by spray processes with submicrometric and nanometric feedstock materials, due to the refinement of the structure and improved coating properties. This paper compares the microstructure and tribological properties of alumina coatings sprayed using conventional atmospheric plasma spraying (APS), and various methods that use finely grained suspension feedstocks, namely, suspension plasma spraying (SPS) and suspension high-velocity oxy-fuel spraying (S-HVOF). Furthermore, the suspension plasma-sprayed Al2O3 coatings have been deposited with radial (SPS) and axial (A-SPS) feedstock injection. The results showed that all suspension-based coatings demonstrated much better wear resistance than the powder-sprayed ones. S-HVOF and axial suspension plasma spraying (A-SPS) allowed for the deposition of the most dense and homogeneous coatings. Dense-structured coatings with low porosity (4 vol.%) and good cohesion to the metallic substrate, containing a high content of α–Al2O3 phase (56 vol.%) and a very low wear rate (0.2 ± 0.04 mm3 × 10−6/(N∙m)), were produced with the S-HVOF method. The wear mechanism of ceramic coatings included the adhesive wear mode supported by the fatigue-induced material delamination. Moreover, the presence of wear debris and tribofilm was confirmed. Finally, the coefficient of friction for the coatings was in the range between 0.44 and 0.68, with the highest values being recorded for APS sprayed coatings.

Plasma Spraying of Self-Lubricating Cr2O3-CaF2 Coatings

1997 ◽  
Author(s):  
F. Vos ◽  
L. Delaey ◽  
M. De Bonte ◽  
L. Froyen
Keyword(s):  
Plasma Spraying ◽  
Matrix Material ◽  
Production Method ◽  
Atmospheric Plasma ◽  
Spray Parameters ◽  
The Matrix ◽  
Preparation Step ◽  
Plasma Sprayed ◽  
The Relationship ◽  
Selection Of

Abstract Results are presented of a project analysing the relationship between the production parameters of plasma sprayed self-lubricating Cr2O3-CaF2 coatings and their structural, wear and lubricating properties. The production method consists of a preparation step where a powder blend of the matrix material (Cr203) and solid lubricant (CaF2) is agglomerated, followed by atmospheric plasma spraying (APS) of the agglomerates. Selection of the most appropriate agglomeration and plasma spray parameters as well as the microstructure of the coatings will be discussed.

Characterization of thermal fatigue damage of thermal barrier produced by atmospheric plasma spraying

2004 ◽  
Vol 187 (2-3) ◽  
pp. 185-193 ◽  
Author(s):  
N. Mesrati ◽  
Q. Saif ◽  
D. Treheux ◽  
A. Moughil ◽  
G. Fantozzi ◽  
...  
Keyword(s):  
Plasma Spraying ◽  
Fatigue Damage ◽  
Thermal Fatigue ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Thermal Barrier

Characterization of Medium Density Particleborads Using Agricultural Residues

2015 ◽  
Vol 1088 ◽  
pp. 656-659
Author(s):  
Ivaldo D. Valarelli ◽  
Rosane A.G. Battistelle ◽  
Barbara Stolte Bezerra ◽  
Luiz A. Melgaço N. Branco ◽  
Eduardo Chahud ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Castor Oil ◽  
Mechanical Characteristics ◽  
Mechanical Characterization ◽  
Raw Materials ◽  
Construction Materials ◽  
Agricultural Residues ◽  
Medium Density ◽  
Polyurethane Resin

In recent years the production of products derived from wood and bamboo are increasing, due to the search for a more rational exploitation of these raw materials. Amongst these products, the particleboards production combine sustainability and rationality in the use of these materials. In this context, this work has the objective to study the application of alternative raw materials in the manufacture of Medium Density Particleboards (MDP), using residues from industrial processimg of coffee and bamboo. MDP had been produced with particles of giganteus bamboo of the Dendrocalamus species and particle of coffee rind in the intermediate layer of the particleboard, bonded with polyurethane resin based on castor oil. The physical and mechanical characterization was carried out accordingly to NBR 14810-3 (2006). The physical properties evaluated were: of water absorption for 2h and 24h; thickness swallowing for 2h and 24h; density, humidity content. The mechanical properties evaluated were: Tensile strength, static bending (MOR and MOE). The results were compared with NBR 14810-2 (2006) and also with the ANSI A208-1 (1993). The physical performance of these particleboards was below the values recommend by the Brazilian norm. Also the mechanical characteristics are not improve, demonstrating that the inclusion of coffee rind did not benefit the physical characteristics and nor the mechanical ones. However it can be used as construction materials for partitions and ceiling panels.

Synthesis and characterization of nanostructured t′-YSZ spherical feedstocks for atmospheric plasma spraying

2018 ◽  
Vol 740 ◽  
pp. 610-616 ◽  
Author(s):  
Feifei Zhou ◽  
You Wang ◽  
Liang Wang ◽  
Yaming Wang ◽  
Wenlong Chen ◽  
...  
Keyword(s):  
Plasma Spraying ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Synthesis And Characterization

Characterization of atmospheric plasma-sprayed Sc2O3–ZrO2 electrolyte coating

2006 ◽  
Vol 177 (19-25) ◽  
pp. 2149-2153 ◽  
Author(s):  
C LI ◽  
C LI ◽  
H LONG ◽  
Y XING ◽  
X NING ◽  
...  
Keyword(s):  
Atmospheric Plasma ◽  
Plasma Sprayed

scholarly journals Structural Changes of Hydroxylapatite during Plasma Spraying: Raman and NMR Spectroscopy Results

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 987
Author(s):  
Robert B. Heimann
Keyword(s):  
Plasma Spraying ◽  
Structural Changes ◽  
Plasma Jet ◽  
Biological Properties ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Decomposition Reactions ◽  
Laser Raman ◽  
Hot Plasma ◽  
Crystallographic Symmetry

Functional osseoconductive coatings based on hydroxylapatite (HAp) and applied preferentially by atmospheric plasma spraying to medical implant surfaces are a mainstay of modern implantology. During contact with the hot plasma jet, HAp particles melt incongruently and undergo complex dehydration and decomposition reactions that alter their phase composition and crystallographic symmetry, and thus, the physical and biological properties of the coatings. Surface analytical methods such as laser-Raman and nuclear magnetic resonance (NMR) spectroscopies are useful tools to assess the structural changes of HAp imposed by heat treatment during their flight along the hot plasma jet. In this contribution, the controversial information is highlighted on the existence or non-existence of oxyapatite, i.e., fully dehydrated HAp as a thermodynamically stable compound.

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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