Comparison of Structure and Wear Properties of Fine-Structured WC-CoCr Coatings Deposited by HVOF and HVAF Spraying Processes

2012 ◽  
Vol 188 ◽  
pp. 422-427 ◽  
Author(s):  
Iosif Hulka ◽  
Viorel Aurel Şerban ◽  
Kari Niemi ◽  
Petri Vuoristo ◽  
Johannes Wolf
Keyword(s):  
High Velocity ◽  
Wear Behaviour ◽  
Tungsten Carbides ◽  
X Ray Diffraction ◽  
Wear Properties ◽  
Fuel Gas ◽  
Cermet Powder ◽  
Pin On Disk ◽  
Oxygen Fuel ◽  
Disk Test

The aim of the work was to study the microstructure and wear properties of fine-structured HVOF and HVAF sprayed WC-10Co-4Cr coatings prepared from powder having submicron-sized tungsten carbides. The coatings were deposited by HVOF (High Velocity Oxygen Fuel) and HVAF (High Velocity Air Fuel) using propane as a fuel gas in both processes, and using oxygen or air as oxidizing gas for combustion, respectively. Nitrogen was used as carrier gas for the powder. Commercially available agglomerated and sintered cermet powder with main carbide sizes under 500 nm was used in this study. Scanning electron microscopy (SEM) and X-ray diffraction were performed in order to characterize the powder and the microstructures formed during the spraying processes. The microhardness HV0.3 of the coatings was investigated and the pin on disk test was used to determine the sliding wear behaviour. The rubber wheel abrasion test was performed in order to determine the abrasion wear resistance of the coatings.

PROPERTIES OF BULK Fe–Ni/CNT NANOCOMPOSITES PREPARED BY MECHANICAL MILLING AND SINTERING

2013 ◽  
Vol 27 (20) ◽  
pp. 1350102 ◽  
Author(s):  
S. AZADEHRANJBAR ◽  
F. KARIMZADEH ◽  
M. H. ENAYATI ◽  
N. MAHMOODI
Keyword(s):  
Xrd Analysis ◽  
High Energy ◽  
X Ray Diffraction ◽  
Wear Properties ◽  
Dry Conditions ◽  
Friction And Wear Properties ◽  
Pin On Disk ◽  
Cold Pressed ◽  
Disk Test ◽  
Composite Samples

The effects of carbon nanotubes (CNTs) on mechanical and tribiological properties of the NiFe /CNT composites prepared by high energy mechanical alloying and hot pressing, were investigated. Bulk samples were prepared by sintering of cold pressed (300 MPa) samples at 1040° C for 1 h. X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and optical microscopy were employed for evaluation of the phase composition, surface morphology and porosities of the samples. The microhardness of as-milled Ni 3 Fe and NiFe powders reached to 720 and 650 VHN, respectively. The hardness of NiFe and Ni 3 Fe bulk samples reduced to 190 and 270 Vickers because of the grain growth during sintering and remaining porosity. The hardness of NiFe -CNT and Ni 3 Fe -CNT bulk samples reached to 360 and 400 Vickers, respectively. The friction and wear properties of the bulk samples were investigated under dry conditions using a pin-on-disk test rig under an applied load of 8 N. The wear rate, mass loss and friction coefficient of the composite samples remarkably reduced in comparison with NiFe and Ni 3 Fe matrix alloys which demonstrate effects of the CNTs on mechanical and tribiological behavior of the composites resulting from the excellent mechanical properties and unique topological structure of the CNTs.

High Temperature Erosion Properties of Thermal Barrier Coatings Produced by Acetylene Sprayed High Velocity Oxygen Fuel Process

2000 ◽  
Author(s):  
M.A. Cole ◽  
R. Walker
Keyword(s):  
High Temperature ◽  
Thermal Barrier Coatings ◽  
High Velocity ◽  
Thermal Barrier ◽  
High Velocity Oxygen Fuel ◽  
Hvof Spraying ◽  
Powder Morphology ◽  
Fuel Gas ◽  
Barrier Coatings ◽  
Oxygen Fuel

Abstract Over the past 30 years, there has been considerable interest in the development of thermally sprayed thermal barrier coatings (TBCs) for aerospace and land based turbine applications. The use of TBCs enables higher operating temperatures, resulting in significant fuel efficiency savings. This paper reports on the development of dense Yttria Stabilised Zirconia (YSZ) thermal barrier coatings produced by High Velocity Oxygen Fuel (HVOF) spraying using acetylene as the fuel gas. The use of a high temperature gas erosion rig allowed the controlled evaluation of erodent size, velocity, impact angle, and temperature on coating performance. The work also covers the optimization of process parameters, including powder morphology, stand-off distance, oxygen to fuel ratio, gas pressures, and flowrates, and their effect on coating characteristics such as deposition efficiency, microhardness, and surface roughness.

scholarly journals Microstructure, Mechanical Properties and Wear Behavior of High-Velocity Oxygen-Fuel (HVOF) Sprayed (Cr3C2-NiCr+Al) Composite Coating on Ductile Cast Iron

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 840 ◽  
Author(s):  
Marzanna Ksiazek ◽  
Lukasz Boron ◽  
Adam Tchorz
Keyword(s):  
Cast Iron ◽  
Electron Microscope ◽  
High Velocity ◽  
Bending Strength ◽  
Wear Behavior ◽  
Ductile Cast Iron ◽  
Wear Behaviour ◽  
Wear Properties ◽  
Alloy Matrix ◽  
X Ray

In the present work Cr3C2-NiCr powder containing Al particles was deposited on ductile cast iron with high-velocity oxy-fuel (HVOF) thermal spray coating technique. An investigation was conducted to determine the role of Al particles in the Cr3C2-NiCr coating produced with HVOF technique on microstructure, mechanical and wear properties in a system Cr2C3-NiCr coating/ductile cast iron. The microstructure of the HVOF-sprayed Cr3C2-NiCr+Al coating was characterized by light microscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and energy dispersive X-ray spectroscopy (EDS). Microstructure analysis reveals the formation of coating with low porosity, good adhesion to the substrate and dense structure with irregularly shaped particles of Al arranged in strips and finely fragmented Cr3C2 particles embedded in a nanocrystalline Ni-Cr alloy matrix. In addition, the results were discussed in reference to examination of bending strength considering cracking and delamination in the system of (Cr3C2-NiCr+Al)/ductile cast iron as well as microhardness and wear resistance of the coating. It was found that the addition of Al particles significantly increased resistance to cracking and wear behaviour in the studied system.

Wear Characteristics of Vacuum Sintered Steels

2011 ◽  
Vol 672 ◽  
pp. 17-22 ◽  
Author(s):  
Mario Rosso ◽  
Eva Dudrová ◽  
Marco Actis Grande ◽  
Róbert Bidulský
Keyword(s):  
Chemical Composition ◽  
Processing Condition ◽  
Surface Hardness ◽  
Wear Behaviour ◽  
Vacuum Furnace ◽  
Processing Conditions ◽  
Wear Characteristics ◽  
Sintered Steels ◽  
Pin On Disk ◽  
Disk Test

The present paper is focused on the wear characteristic of vacuum sintered Cr-Mo-[Mn]-[Cu] steels. The effect of chemical composition and the processing conditions in a vacuum furnace were evaluated. In such furnaces the cooling rate is generally determined by the pressure of the gas (N2) introduced into the chamber, the average cooling rates were calculated in the range of 1240°C to 400°C. The wear characteristics were analyzed as function of the processing and microstructures of the tested alloys through pin on disk test. Sintering of specimens in vacuum together with rapid cooling resulted in the formation of dominant martensitic microstructures with some small bainitic areas. The effect of both surface hardness and microstructure on the wear behaviour of the investigated steels shows the relation between the hardness and the wear rate. The influence of processing condition on the amount of martensite is also presented.

Influence of Sand Variety on Erosion Wear Properties of Nanostructured WC-12Co Coatings Deposited by HVOF Spraying

2011 ◽  
Vol 396-398 ◽  
pp. 472-477
Author(s):  
Yan Liu ◽  
Li Jun Wang ◽  
Hui Chen ◽  
Ming Jing Tu
Keyword(s):  
Failure Mechanism ◽  
Quartz Sand ◽  
High Velocity ◽  
Working Condition ◽  
High Velocity Oxygen Fuel ◽  
Erosion Wear ◽  
Wear Properties ◽  
Hvof Spraying ◽  
Experiment System ◽  
Oxygen Fuel

Nanostructured WC-12Co coating was prepared by means of High Velocity Oxygen Fuel (HVOF) spraying technology in this research. The erosion wear experiment system was developed to simulate the working condition to study the erosion wear properties. The corundum sand with main composition of Al2O3 and quartz sand with main composition of SiO2 were used to investigate the effects of sand variety on the erosion wear properties. The erosion wear failure mechanism of the coatings was also analyzed. The results show that the failure mechanism of the coating eroded by corundum sand is cracking between WC grains, while for the coating eroded by quartz sand, the failure mechanism is microcutting and microploughing.

Study of Microstructure and Adhesion Strength of WC-Co Coating Sprayed by High Velocity Oxygen Fuel

2011 ◽  
Vol 189-193 ◽  
pp. 306-310
Author(s):  
Mei Lin Zhang ◽  
Ming Wei Zhao
Keyword(s):  
Adhesion Strength ◽  
High Velocity ◽  
Layer Structure ◽  
Steel Substrate ◽  
High Velocity Oxygen Fuel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grit Blasting ◽  
High Adhesion ◽  
Oxygen Fuel

WC-12 %Co powders were sprayed by high velocity oxygen fuel (HVOF) to prepare coatings on carbon steel substrate, which was pretreated by electrospark and grit blast before spraying. The surface coating of WC-Co and the intermediate layer structure were studied by scanning electron microscopy and X-ray diffraction. The adhesion strength of the coating was measured by a scratching tester. Results show that the roughness value of the grit blasting and electrospark strengthened surface were 60~70 μm and 40~50 μm, respectively. The coating pretreated by grit blast and electrospark was dense and was bonded well with the substrate. The heat affected zone of the grit blasted specimen was larger than that of the electrospark pretreated one. The average adhesion strength of the coating pretreated with grit blasting and that with eletrospark were 35.00 N and 12.48 N, respectively. The reasion of the high adhesion strength of the grit blasting coating is discussed.

Sliding Wear Properties of HVOF Sprayed WC-10Co4Cr Coatings With Conventional Structure and Bimodal Structure Under Different Loads

2021 ◽  
Vol 144 (1) ◽  
Author(s):  
Yong-Kuan Zhou ◽  
Jia-Jie Kang ◽  
Wen Yue ◽  
Xiao-Bin Liu ◽  
Zhi-Qiang Fu ◽  
...  
Keyword(s):  
Sliding Wear ◽  
Friction And Wear ◽  
X Ray Diffraction ◽  
Indentation Fracture ◽  
Wear Properties ◽  
Bimodal Structure ◽  
Indentation Fracture Toughness ◽  
Lower Porosity ◽  
Conventional Structure ◽  
Oxygen Fuel

Abstract The WC-10Co4Cr coatings with conventional structure and bimodal structure were sprayed by high-velocity oxygen fuel (HVOF) technology. The phase compositions and morphologies of the WC-10Co4Cr powders and coatings were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The microhardness, porosity, bonding strength, elastic modulus, and indentation fracture toughness of the conventional coating (Conventional) and the bimodal coating (Bimodal) were also studied. The sliding wear properties of the Conventional and the Bimodal against Si3N4 counterballs under different loads at room temperature (∼25 °C) were investigated using a friction and wear tester. Compared with the Conventional, the Bimodal has denser microstructure, lower porosity, more excellent mechanical properties, and the Bimodal has better wear resistance than the Conventional under different loads. The two coatings under 15 N and 30 N only exhibit abrasive and slightly adhesive wear mechanism, while in the load application of 45 N, additional mechanism which is fatigue is detected and causes flaking of the coating.

scholarly journals Evaluation of Sliding Wear Behaviour for STD11 Coated with TiCN Using the Pin-on-Disk Test

2020 ◽  
Vol 967 ◽  
pp. 012061
Author(s):  
J H Bang ◽  
J H Song ◽  
G H Bae ◽  
N S Park ◽  
S O Choi ◽  
...  
Keyword(s):  
Sliding Wear ◽  
Wear Behaviour ◽  
Pin On Disk ◽  
Sliding Wear Behaviour ◽  
Disk Test
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