scholarly journals Microstructure and Selected Properties of Cr3C2–NiCr Coatings Obtained by HVOF on Magnesium Alloy Substrates

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2775 ◽  
Author(s):  
Ewa Jonda ◽  
Leszek Łatka ◽  
Wojciech Pakieła
Keyword(s):  
Magnesium Alloy ◽  
Az31 Alloy ◽  
Composition Analysis ◽  
High Velocity Oxygen Fuel ◽  
Instrumented Indentation ◽  
Hvof Spraying ◽  
Alloy Substrate ◽  
Magnesium Az31 ◽  
Abrasive Erosion ◽  
Oxygen Fuel

In present work the Cr3C2–NiCr coating was deposited on magnesium alloy substrate with high velocity oxygen fuel (HVOF) spraying. The microstructure of the samples has been characterized by means of electron microscopy, SEM and phase composition analysis carried out. The porosity of coatings has been also estimated. Finally, tests of selected mechanical properties, such as instrumented indentation, abrasive erosion have been performed. The results of the investigations confirmed that dense, homogeneous and well-adhered Cr3C2–NiCr cermet coating is possible to obtain onto the magnesium AZ31 alloy substrate. Moreover, the coatings exhibit high resistance to erosion.

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.

Comparative analysis of tribological behavior of plasma- and high-velocity oxygen fuel-sprayed WC-10Co-4Cr coatings

2017 ◽  
Vol 69 (2) ◽  
pp. 325-332 ◽  
Author(s):  
Shiyu Cui ◽  
Qiang Miao ◽  
Wenping Liang ◽  
Yi Xu ◽  
Baiqiang Li
Keyword(s):  
Plasma Spraying ◽  
High Velocity ◽  
Wear Mechanisms ◽  
Wear Behavior ◽  
High Velocity Oxygen Fuel ◽  
Hvof Spraying ◽  
Content Type ◽  
Q235 Steel ◽  
Oxygen Fuel ◽  
Sprayed Coatings

Purpose The purpose of this study is to prepare WC-10Co-4Cr coatings using two processes of plasma spraying and high-velocity oxygen fuel (HVOF) spraying. The decarburization behaviors of the different processes are analyzed individually. The microstructural characteristics of the as-sprayed coatings are presented and the wear mechanisms of the different WC–10Co–4Cr coatings are discussed in detail. Design/methodology/approach The WC–10Co–4Cr coatings were formed on the surface of Q235 steel by plasma and HVOF spraying. Findings Plasma spraying causes more decarburizing decomposition of the WC phase than HVOF spraying. In the plasma spraying process, η(Cr25Co25W8C2) phase appears and the C content decreases from the top surface of the coating to the substrate. Practical implications In this study, two WC–10Co–4Cr coatings on Q235 steel prepared by plasma and HVOF spraying were compared with respect to the sliding wear behavior. Originality/value The wear mechanisms of the plasma- and HVOF-sprayed coatings were abrasive and oxidation, respectively.

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.

Characteristics of MCrAlY Coatings Sprayed by High Velocity Oxygen-Fuel Spraying System

1999 ◽  
Vol 122 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Y. Itoh ◽  
M. Saitoh ◽  
M. Tamura
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
High Velocity ◽  
Gas Turbines ◽  
High Velocity Oxygen Fuel ◽  
Hvof Spraying ◽  
Vacuum Plasma ◽  
Mcraly Coatings ◽  
Plasma Sprayed ◽  
Oxygen Fuel

High velocity oxygen-fuel (HVOF) spraying system in open air has been established for producing the coatings that are extremely clean and dense. It is thought that the HVOF sprayed MCrAlY (M is Fe, Ni and/or Co) coatings can be applied to provide resistance against oxidation and corrosion to the hot parts of gas turbines. Also, it is well known that the thicker coatings can be sprayed in comparison with any other thermal spraying systems due to improved residual stresses. However, thermal and mechanical properties of HVOF coatings have not been clarified. Especially, the characteristics of residual stress, that are the most important property from the view point of production technique, have not been made clear. In this paper, the mechanical properties of HVOF sprayed MCrAlY coatings were measured in both the case of as-sprayed and heat-treated coatings in comparison with a vacuum plasma sprayed MCrAlY coatings. It was confirmed that the mechanical properties of HVOF sprayed MCrAlY coatings could be improved by a diffusion heat treatment to equate the vacuum plasma sprayed MCrAlY coatings. Also, the residual stress characteristics were analyzed using a deflection measurement technique and a X-ray technique. The residual stress of HVOF coating was reduced by the shot-peening effect comparable to that of a plasma spray system in open air. This phenomena could be explained by the reason that the HVOF sprayed MCrAlY coating was built up by poorly melted particles. [S0742-4795(00)00701-8]

scholarly journals Microstructure Characteristics and Properties of HVOF Sprayed Ni-Based Alloy Nano-h-BN Self-Lubricating Composite Coatings

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Xiaofeng Zhang ◽  
Long Zhang ◽  
Zhenyi Huang
Keyword(s):  
Solid Lubricant ◽  
Composite Coatings ◽  
Metallic Matrix ◽  
Medium Carbon Steel ◽  
High Velocity Oxygen Fuel ◽  
Hvof Spraying ◽  
Properties Of Coatings ◽  
Medium Carbon ◽  
Microstructure Characteristics ◽  
Oxygen Fuel

A Ni-based alloy/nano-h-BN self-lubricating composite coating was produced on medium carbon steel by high velocity oxygen fuel (HVOF) spraying technique. The powder feedstocks for HVOF spraying were prepared by ball milling and agglomerated the nano-h-BN with Ni-based alloy powders. The microstructure and mechanical properties of coatings have been investigated. With the increasing of h-BN contents, some delaminations appeared gradually in the coatings and a continuous network with h-BN phase embedded formed in the metallic matrix. The average microhardness of the self-lubricating coating was a little lower for the addition of soft solid lubricant. The friction coefficient of coatings is in the ranges of 0.38–0.48 and 0.38–0.52 at ambient temperature and 400°C, respectively. The maximum bonding strength of coatings reached 23.83 MPa.

scholarly journals Increasing the Lightweight Potential of Composite Cold Forging by Utilizing Magnesium and Granular Cores

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 32
Author(s):  
Robin Gitschel ◽  
Felix Kolpak ◽  
Oliver Hering ◽  
A. Erman Tekkaya
Keyword(s):  
Magnesium Alloy ◽  
Granular Media ◽  
Az31 Alloy ◽  
Cold Forging ◽  
Forming Limit ◽  
Process Route ◽  
Wide Range ◽  
Shear Yield ◽  
Magnesium Az31 ◽  
Hollow Shafts

In this paper a process sequence, that uses forward rod extrusion with cold forged C15 steel cup billets to produce lightweight shafts, is presented. The steel cup billets feature either a lightweight magnesium alloy core or a granular medium core that is removed after forming to obtain hollow shafts without the need of complex tools and highly loaded mandrels. It is shown that composite shafts featuring magnesium cores can be produced for a wide range of extrusion strains. Due to high hydrostic pressures in forward rod extrusion, the forming limit of magnesium at room temperature can be expanded. The observed bond strength between core and sheath is below the shear yield strength of utilized magnesium AZ31 alloy. Hollow shafts are successfully produced with the presented process route by utilizing zirconium oxide beads or quartz sand as a lost core. As the law of constant volume in metal forming is violated by compressible granular media, a simulation approach using a modified Drucker-Prager yield surface to model these materials is validated to provide a tool for efficient process design. Granular cores and magnesium alloy cores offer new possibilities in production of lightweight shafts by means of composite cold forging. Both process variants allow for higher weight savings than composite shafts based on aluminum cores.

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