Hard Arc-Sprayed Coating with Enhanced Erosion and Abrasion Wear Resistance

2000 ◽  
Author(s):  
S. Dallaire
Keyword(s):  
Ceramic Coatings ◽  
High Energy ◽  
Arc Spraying ◽  
Cored Wire ◽  
Industrial Sectors ◽  
Wear Protection ◽  
Abrasion Wear ◽  
Sprayed Coating ◽  
Impact Angles ◽  
Sprayed Coatings

Abstract Exposed to particle erosion environments, metal-sprayed coatings are damaged by micro-machining and ploughing at low impact angles. The generation and propagation of subsurface lateral cracks at high impacting angles damage single-phase ceramic coatings. Therefore, multicomponent coatings deposited by high-energy processes have been widely used to provide wear protection in most of the applications. As commercial arc-sprayed coatings have been used to a limited extent in applications involving erosion and abrasion wear, developing attractive wear resistant arc-sprayed coatings has been found necessary. A cored wire formulation, referred to as Alpha-1800, has been developed to produce tailored arc-sprayed coatings that are tough enough to resist particle impacts at 90° and sufficiently hard to deflect eroding particles at low impact angles. Typical 1 mm-thick coatings composed of ductile and hard phases with Knoop hardness reaching 1800 kg/mm2 were easily produced by arc spraying the cored wire with air. Coatings were: 1) erosion tested at 25°C and higher temperatures at impact angles of 25° and 90° in a gas-blast erosion rig, 2) slurry erosion tested at impact angles of 25° and 90°, 3) abrasion wear tested using the ASTM G-65 test procedure. Results show that coatings produced with the new cored wire are at least 5 times more erosion resistant and 10 times more abrasion resistant than coatings produced by arc spraying commercial cored wires. The performance of the new arc-sprayed coating can be compared with that of high-energy WC-based coatings. Being thermally stable up to 850°C, arc-sprayed coatings produced with the new cored wire are attractive for applications in many industrial sectors up to high temperatures.

Erosion Resistance of Arc Sprayed Coatings to Iron Ore at 25°C and 330°C

1997 ◽  
Author(s):  
S. Dallaire ◽  
H. Levert
Keyword(s):  
Iron Ore ◽  
Erosion Resistance ◽  
Arc Spraying ◽  
Spray Parameters ◽  
Ore Pellets ◽  
Industrial Oil ◽  
Reference Specimens ◽  
Impact Angles ◽  
Thick Coatings ◽  
Sprayed Coatings

Abstract Iron ore pellets are sintered and reduced in continuous large industrial oil-fired furnaces. From the furnace, large volumes of hot gas are sucked by powerful fans. Being exposed to gas-borne iron particles and temperatures ranging between 125°C and 328°C fan components are rapidly deteriorated. Extensive part repair or replacement are required for maintaining a profitable operation. The arc spraying technique has been suggested for repair provided it could produce erosion resistant coatings. Commercial wires were arc sprayed using various spray parameters to produce thick coatings. Arc-sprayed coatings and reference specimens were erosion tested at 25°C and 330°C and impact angles of 25° and 90° in a laboratory gas-blast erosion rig. This device was designed to impact materials with coarse (32 -300 μm) iron ore particles at a speed of 100 m/s. The volume loss was accurately measured with a laser profilometer. Few arc sprayed coatings exhibited erosion resistance comparable with structural steel at low impact angles. Erosion of arc sprayed coatings and reference specimens dramatically increases at 330°C for both 25° and 90° impact angles. Erosion-enhanced oxidation was found responsible for the increase in wastage above room temperature. Though arc spraying can be appropriate for on-site repair, the development of erosion resistant coatings is required for intermediate temperatures.

Quantities and Properties of Layers Sprayed with Cored Wire of Type Fe-Cr-C

1998 ◽  
Author(s):  
H. Drzeniek ◽  
W. Milewski
Keyword(s):  
Arc Spraying ◽  
Coating Structure ◽  
Cored Wire ◽  
Spraying Parameters ◽  
Parameter Variations ◽  
Sprayed Coatings ◽  
Spraying Method

Abstract Results of macro- and microhardness investigations of newly developed coatings are presented in this paper. The coatings were produced with flame- and arc spraying technique. The coating structure and hardness is significantly influenced by the spraying method and spraying parameters. It will be shown that properties for flame sprayed coatings are more effected by parameter variations than for arc sprayed coatings. A higher hard-ness, a greater density and a better particle cohesion can be obtained by using the arc spraying method.

Characterization of thermal barrier coatings formed by electon-beam physical vapor deposition (EB-PVD)

1989 ◽  
Vol 47 ◽  
pp. 426-427
Author(s):  
Ozer Unal
Keyword(s):  
Thermal Barrier Coatings ◽  
Physical Vapor Deposition ◽  
Ceramic Coating ◽  
High Vacuum ◽  
Ceramic Coatings ◽  
High Energy ◽  
Thermal Barrier ◽  
Protective Oxide ◽  
Barrier Coatings ◽  
Energy Beam

Interest in ceramics as thermal barrier coatings for hot components of turbine engines has increased rapidly over the last decade. The primary reason for this is the significant reduction in heat load and increased chemical inertness against corrosive species with the ceramic coating materials. Among other candidates, partially-stabilized zirconia is the focus of attention mainly because ot its low thermal conductivity and high thermal expansion coefficient.The coatings were made by Garrett Turbine Engine Company. Ni-base super-alloy was used as the substrate and later a bond-coating with high Al activity was formed over it. The ceramic coatings, with a thickness of about 50 μm, were formed by EB-PVD in a high-vacuum chamber by heating the target material (ZrO2-20 w/0 Y2O3) above its evaporation temperaturef >3500 °C) with a high-energy beam and condensing the resulting vapor onto a rotating heated substrate. A heat treatment in an oxidizing environment was performed later on to form a protective oxide layer to improve the adhesion between the ceramic coating and substrate. Bulk samples were studied by utilizing a Scintag diffractometer and a JEOL JXA-840 SEM; examinations of cross-sectional thin-films of the interface region were performed in a Philips CM 30 TEM operating at 300 kV and for chemical analysis a KEVEX X-ray spectrometer (EDS) was used.

Sliding Wear Behavior of Remelted Al2O3-TiO2 Plasma Sprayed Coatings on Titanium

2016 ◽  
Vol 254 ◽  
pp. 231-236 ◽  
Author(s):  
Ion Dragoş Uţu ◽  
Gabriela Marginean ◽  
Iosif Hulka ◽  
Viorel Aurel Şerban
Keyword(s):  
Sliding Wear ◽  
Wear Behavior ◽  
Pure Titanium ◽  
Titanium Substrate ◽  
Atmospheric Plasma ◽  
Wear Properties ◽  
Before And After ◽  
Sprayed Coating ◽  
Pin On Disk ◽  
Sprayed Coatings

Microstructure and wear properties of the Al2O3-13.wt% TiO2 thermally sprayed coatings before and after remelting were investigated in this study. The coatings were deposited on a pure titanium substrate using the atmospheric plasma spraying (APS) process. The as-sprayed coatings were electron beam (EB) modified in order to improve their compactness and bonding strength.The effect of EB remelting on the microstructure, phase constituents and wear properties was investigated using scanning electron microscopy (SEM), X-Ray diffraction technique and hardness measurements. The sliding wear behavior was tested using a pin on disk method.The results showed that the remelting process had a positive effect removing the lamellar defect of the as-sprayed coating and improving the compactness, hardness and wear behavior.

Plasma Arc Spraying of Cu-Ti-Zr-Ni Amorphous Alloys

2000 ◽  
Author(s):  
D.J. Sordelet ◽  
P. Huang ◽  
M.F. Besser ◽  
E. Lepecheva
Keyword(s):  
Cross Sections ◽  
Metallic Glasses ◽  
High Strength ◽  
Amorphous Structure ◽  
High Fracture Toughness ◽  
Arc Spraying ◽  
Plasma Arc ◽  
High Fracture ◽  
Spray Coatings ◽  
Sprayed Coatings

Abstract A brief feasibility study was performed to produce thermal spray coatings using gas atomized powders of Cu47Ti34-xZr11Ni8Six, where x=0 and 1. These alloys have previously been shown to be capable of forming metallic glasses having thick (1-2 cm) cross sections because they can be cooled from the melt at relatively low cooling rates (e.g., 100-102Ks-1). The properties of these metallic glasses include high strength, high elasticity and high fracture toughness. Amorphous plasma arc sprayed coatings were produced which were close in composition to the starting powders, and exhibited comparable glass transition and crystallization behavior. The amorphous structure of the as-sprayed coatings was used as a source for forming a range of partially devitrified and fully crystallized structures. The average hardness of the coatings increased from around 6 GPa to near 10 GPa as the degree of crystallization increased.

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 Effects of Ambient Conditions on the Dielectric Properties of Thermally Sprayed Ceramic Coating

2018 ◽  
Author(s):  
M Niittymäki ◽  
B. Rotthier ◽  
K. Lahti ◽  
T. Suhonen ◽  
J Metsäjoki
Keyword(s):  
Dielectric Properties ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Thermal Spraying ◽  
Ceramic Coatings ◽  
Alumina Coating ◽  
Ambient Conditions ◽  
Coating Materials ◽  
Sprayed Coating ◽  
Thermally Sprayed

<p>Thermal spraying techniques are used to manufacture insulating coatings especially for demanding applications like fuel cells where normal insulating materials cannot be used. In electrical insulation applications, the mostly used coating materials are aluminum oxide (Al2O3), magnesium oxide (MgO) and magnesium aluminate (MgAl2O4). Dielectric properties of thermally sprayed ceramic coatings are strongly affected by ambient conditions, and in addition to this they are not well documented in the literature. In this paper the effects of environmental conditions on certain dielectric properties of a thermally sprayed coating are studied. DC resistivity as well as permittivity and losses at different frequencies at relative humidities of 20 % and 45 % at temperature of 20 °C, 40 °C and 60 °C will be reported in the paper for Al2O3 samples sprayed using HVOF (High Velocity Oxygen Fuel) technique. DC dielectric breakdown strength is also studied for the HVOF alumina coating at temperature of 20 °C and relative humidity of 20 %. Effects of ambient conditions and coating material composition are also analyzed.</p>

Application of Plane Fractal Geometry to Adhesion Strength of Thermal Sprayed Coatings

2000 ◽  
Author(s):  
S. Amada ◽  
T. Hirose
Keyword(s):  
Cross Section ◽  
Fractal Geometry ◽  
Surface Characteristics ◽  
Ceramic Coatings ◽  
Average Surface Roughness ◽  
Roughened Surface ◽  
Fractal Characteristics ◽  
Sprayed Coatings ◽  
Thermal Sprayed Coatings ◽  
Height Data

Abstract Adhesion of ceramic coatings considerably depends on the surface characteristics of blasted substrates. The roughened surfaces have two kinds of topographical characteristics, one is of their cross section and the other is of planar. The roughened surfaces is generated by angled grit-blasting process which can be expected to improve the adhesion of ceramic coatings. The topography of the roughened surfaces has fractal characteristics in their cross section and has been more effectively related to the adhesive strength of ceramic coatings than average surface roughness traditionally used. This paper presents that fractal characteristics is evaluated in the planar topography of the blasted surfaces and shows that the planar fractal characteristics is closely related adhesion of ceramic coatings. The planar fractal dimension is evaluated by SIA (Slit Island Analysis) which needs the height data on the roughened surface. Those data are obtained by a laser-microscope in confocal type.

A Study on the Arc Spraying of 7Cr13 Cored Wire and Tribological Properties of the Composite Coating

1998 ◽  
Author(s):  
B. Xu ◽  
S. Ma ◽  
J. Wang ◽  
J. Tan
Keyword(s):  
Bond Strength ◽  
Composite Coating ◽  
Tribological Properties ◽  
High Hardness ◽  
Wear Resistant Coating ◽  
Arc Spraying ◽  
Metallurgical Process ◽  
Cored Wire ◽  
Wear Resistant ◽  
Wire Arc Spraying

Abstract For the purpose of getting high hardness and high wear-resistant coating by arc spraying technology, the arc spraying of 7Cr13 cored wire is adopted in this paper. The metallurgical process of the cored wire arc spraying is discussed. The bond strength, hardness and tribological properties of the composite coating are investigated.

Characterization of Structure of Thermally Sprayed Coating

1998 ◽  
Author(s):  
C.J. Li ◽  
Y. He ◽  
A. Ohmori
Keyword(s):  
Lamellar Structure ◽  
Structural Parameters ◽  
Lamellar Thickness ◽  
Pore Networks ◽  
Bonding Ratio ◽  
Sprayed Coating ◽  
The Relationship ◽  
Thermally Sprayed ◽  
Sprayed Coatings

Abstract The structure of a thermally sprayed coating is generally of lamellar structure. There is generally porosity in the coating. The examination shows that the relationship between properties and porosity for conventionally processed porous materials is difficult to be applied to thermally sprayed coating because of complex pore networks. The lamellar structure of the coating and the bonding at the interfaces between lamellae often determine the properties of coating. It is generally difficult to evaluate quantitatively the structure of a thermally sprayed coating because of complicated pore networks in the coating. With the filling of the material different from the composition of the coating into the pores the structure of the coating including nonbonded interface area and also generally referred pores can be visualized. According to the distribution of filler in the coating the structure of a coating can be quantitatively evaluated using structural parameters such as lamellar thickness, lamellar bonding ratio, the width of interface gap and so on. The structural parameters necessary to describe the lamellar structure of thermal sprayed coatings and a method based on the pore filling and analysis of the distribution of filled materials are proposed.

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