scholarly journals Microstructure and Sliding Wear Resistance of Plasma Sprayed Al2O3-Cr2O3-TiO2 Ternary Coatings from Blends of Single Oxides

Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 42 ◽  
Author(s):  
Maximilian Grimm ◽  
Susan Conze ◽  
Lutz-Michael Berger ◽  
Gerd Paczkowski ◽  
Thomas Lindner ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Sliding Wear ◽  
Spray Coating ◽  
Thermal Spray Coating ◽  
Corrosion And Wear ◽  
Atmospheric Plasma ◽  
Spray Parameters ◽  
Oxide Materials ◽  
Spray Process ◽  
Plasma Sprayed

Al2O3, Cr2O3, and TiO2 are most commonly used oxide materials for thermal spray coating solutions. Each oxide shows unique properties comprising behavior in the spray process, hardness, corrosion, and wear resistance. In order to exploit the different advantages, binary compositions are often used, while ternary compositions are not studied yet. Atmospheric plasma spraying (APS) of ternary compositions in the Al2O3-Cr2O3-TiO2 system was studied using blends of plain powders with different ratios and identical spray parameters. Coatings from the plain oxides were studied for comparison. For these powder blends, different deposition rates were observed. The microstructure, roughness, porosity, hardness, and wear resistance were investigated. The formation of the splats from particles of each oxide occurs separately, without interaction between the particles. The exception are the chromium oxide splats, which contained some amounts of titanium. The predominant oxide present in each blend has a decisive influence on the properties of the coatings. While TiOx causes a low coating porosity, the wear resistance can be increased by adding Cr2O3.

Study on Microstructure of Nano-Zirconia Coating by Atmospheric Plasma Spraying

2014 ◽  
Vol 618 ◽  
pp. 43-49
Author(s):  
Ying Chang ◽  
Qin Biao Zhu ◽  
Shi Jie Dong ◽  
Hui Hu Wang ◽  
Kuan He Du
Keyword(s):  
Electron Microscopy ◽  
Layer Structure ◽  
Spray Coating ◽  
Thermal Spray Coating ◽  
Ceramic Particle ◽  
Atmospheric Plasma ◽  
Zirconia Coating ◽  
Technical Parameters ◽  
Columnar Grains ◽  
Plasma Sprayed

On the basis of successfully preparing nanozirconia coating via reasonable spraying technical parameters, the cross section and surface morphology of coating were determined by scan electron microscopy (SEM), and the ceramic particle sizes of coating were determined by transmission electron microscopy (TEM). Experimental results indicate that plasma sprayed zirconia coating possesses typical layer structure of thermal spray coating, in which columnar grains pile up together. Meanwhile, the non-molten nanopowders coexist with the layer structure. In addition, the equiaxial grains exist in the zirconia coating according to TEM, but the grain size is not uniform.

Optimization of Thermal Spray Parameters of NiAl/Cr2C3 Coating by Taguchi Method

2019 ◽  
Vol 295 ◽  
pp. 9-14 ◽  
Author(s):  
M. Tahari ◽  
B. Luo ◽  
J. Geng ◽  
D. Jing ◽  
M. Hatami
Keyword(s):  
Wear Resistance ◽  
Thermal Spray ◽  
Feed Rate ◽  
Spray Coating ◽  
Wear Test ◽  
Thermal Spray Coating ◽  
Spray Parameters ◽  
Spray Distance ◽  
Powder Feed Rate ◽  
Powder Feed

In this study the effect of thermal spray process on wear resistance of NiAl/Cr2C3 thermal spray coating has been investigated. For this purpose the NiAl power mixed with 10 %wt. Cr2C3 powder and milled for 1 hrs at argon atmosphere. The APS parameters such as voltage (V), current (A), spray distance (mm), powder feed rate (gr/min), were optimize using a response surface methodology. For investigation effect of spray parameters on quality of coatings, the porosity and wear resistance of coatings analyzed with SEM and pin on disk wear test. Results show that increase of voltage and current are more effective other parameters. Increasing of powder feed rate and spray distance raised porosity of coatings intensively.

scholarly journals Microstructure and Properties of Atmospheric Plasma Sprayed (Al,Cr)2O3–TiO2 Coatings from Blends

2021 ◽  
Author(s):  
Maximilian Grimm ◽  
Susan Conze ◽  
Lutz-Michael Berger ◽  
Rico Drehmann ◽  
Thomas Lampke
Keyword(s):  
Solid Solution ◽  
Wear Resistance ◽  
Sliding Wear ◽  
Atmospheric Plasma ◽  
Coating Properties ◽  
High Corrosion Resistance ◽  
Abrasion Wear ◽  
Small Change ◽  
Plasma Sprayed ◽  
Insulating Properties

AbstractCoatings prepared from chromia-rich (Al,Cr)2O3 solid solution (ss) feedstock powders are intended to improve the properties of Cr2O3 coatings, but are rarely studied so far. In this work, the processability of a commercial (Al,Cr)2O3 solid solution (ss) powder containing 78 wt.% Cr2O3 by atmospheric plasma spraying (APS), the corresponding coating microstructures and properties were investigated. Possible further improvements were expected by blending with 2, 23 and 54 wt.% TiOx powder. For comparison, plain Cr2O3 and TiOx coatings were studied as well. The microstructures were analyzed using SEM, EDS and XRD measurements. Hardness (HV0.3) was measured, as well as the dry unidirectional sliding wear resistance and the abrasion wear resistance (ASTM G65). Moreover, the corrosion and electrical insulating properties were measured. The (Al,Cr)2O3 ss showed only a small change of the composition, and the formation of γ-Al2O3, as found for alumina-rich (Al,Cr)2O3 ss powders, was avoided. Compared to the plain chromia coating, some improvements of the processability and coating properties for the ss (Al,Cr)2O3 coating were found. The most balanced coating performance was achieved by blending the ss (Al,Cr)2O3 with 2 wt.% TiOx, as this coating showed both a high sliding and abrasion wear resistance, in combination with a high corrosion resistance.

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.

Splashing of Nickel Droplets During Plasma Spraying

2000 ◽  
Author(s):  
V. Pershin ◽  
I. Thomson ◽  
S. Chandra ◽  
J. Mostaghimi
Keyword(s):  
Substrate Temperature ◽  
Nickel Powder ◽  
Steel Substrate ◽  
Spray Coating ◽  
Building Blocks ◽  
Thermal Spray Coating ◽  
Substrate Heating ◽  
Polished Stainless Steel ◽  
Plasma Sprayed ◽  
Droplet Impacts

Abstract Individual splats are the building blocks of any thermal spray coating. Near the coating-substrate interface, they affect coating properties like adhesion strength. This article examines the effect of substrate heating on droplet splashing. Nickel powder was plasma-sprayed onto a polished stainless steel substrate at various temperatures and the resulting splats were analyzed. Droplet splashing was observed experimentally for three different cases: low substrate temperature, high substrate temperature, and droplet-splat interaction. Mechanisms for splashing were explained with the help of computer-generated nickel droplet impacts. The article proposes that the jetting of molten metal is not triggered by the formation of a central splat but rather a solidified ring on the periphery of the splat. It was observed that, on substrates below 350 deg C, splashing is triggered by solidification at the edge of the spreading droplet. Interactions with previously deposited splats also cause droplets to splash.

scholarly journals Crack Growth Tests in Air Plasma-Sprayed Yttria Coatings for Alumina Ceramic Matrix Composites

Ceramics ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 514-524
Author(s):  
Stefan Hackemann ◽  
Marion Bartsch
Keyword(s):  
Crack Growth ◽  
Bending Strength ◽  
Ceramic Matrix Composites ◽  
Atmospheric Plasma ◽  
Crack Growth Behavior ◽  
Matrix Composites ◽  
Air Plasma ◽  
Spray Process ◽  
Aging Conditions ◽  
Plasma Sprayed

Yttria coatings for all-oxide combustor walls were tested for their crack-growth behavior. These environmental and thermal barrier Y2O3-coatings were processed by atmospheric plasma spraying (APS). The stiffness and strength were measured for as-received and aged samples that were heat treated at 1000 °C, 1100 °C and 1200 °C for a 10 h dwell time. The results show a clear development with respect to the aging conditions. The changes of the modulus and the bending strength indicate that the microstructural changes are not completed, even after aging at 1200 °C for 10 h. The fracture toughness was tested for different orientations on samples aged at 1200 °C. Bending tests as well as indentation experiments were conducted. Furthermore, a bending device was designed to observe the crack-growth in situ. The device had to be rigid and is driven by a piezo stack. The crack growth resistance shows differences in the rise of the R-curves for different orientations of the crack propagation. This is in agreement with the microstructure that results from the plasma spray process.

Microstructure and Wear Resistance of Laser Cladding of Ni-Based Alloy on Copper Substrate

2010 ◽  
Vol 663-665 ◽  
pp. 1061-1064 ◽  
Author(s):  
Yun Shan Wang ◽  
Neng Wen Liu ◽  
Fu Dong Zhu
Keyword(s):  
Wear Resistance ◽  
Laser Cladding ◽  
Copper Substrate ◽  
Spray Coating ◽  
Hardness Test ◽  
Spray Process ◽  
Plasma Spray Process ◽  
Coating Microstructure ◽  
Laser Remelt ◽  
Wear Tests

In order to improve the service life of copper crystallizer, a layer of Ni-based alloy on thick copperplate surface was performed by plasma spray process, and then YAG pulsed laser was used to remelt spray coating. Microstructure analysis, hardness test, and the wear resistance comparison experiments were taken to the specimen. The result shown that the Ni-based alloy cladding, metallurgy bonding with the copperplate, can be performed by taking the method of the YAG laser remelt technology; the structure of the cladding is compact, without defects such as pores and cracks. The micro hardness of cladding zone is between 450-490HV, which is much higher than that of the copper substrate (about 90 HV). The wear tests showed the laser cladding layer performed 14 times higher wear resistance compared to copper substrate.

scholarly journals Mechanical Properties and Sliding Wear Resistance of Suspension Plasma Sprayed YSZ Coatings

2020 ◽  
Vol 14 (4) ◽  
pp. 307-314
Author(s):  
Leszek Łatka ◽  
Mirosław Szala ◽  
Wojciech Macek ◽  
Ricardo Branco
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Sliding Wear ◽  
Plasma Sprayed

Elasticity Characteristics of Plasma Spray Coatings

1996 ◽  
Author(s):  
L. Dekhtyar ◽  
A. Kleyman ◽  
S. Berman ◽  
V. Andreychuk
Keyword(s):  
Residual Stresses ◽  
Thermal Spray ◽  
Coating Thickness ◽  
Quantitative Methods ◽  
Spray Coating ◽  
Thermal Spray Coating ◽  
Spray Parameters ◽  
Spray Coatings ◽  
Real Value ◽  
Elastic Characteristics

Abstract Future development of thermal spray processes and new composite materials raises an important problem concerning the transition from qualitative to quantitative methods of coatings evaluation. It is well known that thermal spray coating deposition in most cases is accompanied by the formation of temporal and residual stresses through the coating thickness. For proper evaluation of formed stressed state it is extremely important to know the real value of elastic characteristics in different layers of the coating. This problem has become more complicated taking into consideration the variety of materials, different spray parameters, number of coating layers and extreme service conditions. These values can be obtained only from experimentation. Elastic characteristics (EC) could be used in many calculations, such as durability, stiffness, fatigue, vibration and others. This paper describes new methods of experimental determination of elastic characteristics presumed as variable throughout the coating thickness. Influence of coating composition, particle size of initial powders, spray parameters, post-treatment and other factors on elastic modulusses were studied. Obtained experimental data for different materials supplement existing data and can be used for evaluation of residual stresses and other purposes.

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