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.

Titanium Based Composite Coatings Deposited by High Velocity Oxygen Fuel (HVOF) and Plasma Spraying Methods

2013 ◽  
Vol 551 ◽  
pp. 127-132
Author(s):  
Asma Salman ◽  
Brian Gabbitas ◽  
De Liang Zhang
Keyword(s):  
Plasma Spraying ◽  
High Velocity ◽  
Composite Coatings ◽  
High Energy ◽  
High Velocity Oxygen Fuel ◽  
Air Plasma ◽  
Feedstock Powder ◽  
Hvof Spraying ◽  
Sprayed Coating ◽  
Oxygen Fuel

The study involves a special class of composites called interpenetrating phase composites (IPCs). The Ti(Al,O)/Al2O3 composite was produced using high energy mechanical milling of a mixture of TiO2 and Al followed by a high temperature self-propagating reaction. Characteristics of the feedstock powder were improved by treating it with an organic binder. The feedstock powder was thermally sprayed on to a substrate using high velocity oxygen fuel (HVOF) and air plasma spraying methods. The spraying methods resulted in coatings with significantly different microstructures. Compared with plasma sprayed coating, the coating produced by a HVOF spraying method showed a much finer and densely packed microstructure.

scholarly journals Influence of Chromium Concentration on the Abrasive Wear Of Ni-Cr-B-Si Coatings Applied by High-Velocity Oxygen Fuel

2021 ◽  
Author(s):  
Zhetcho Doinov Kalitchin ◽  
Mara Krumova Kandeva ◽  
Yana Petrova Stoyanova
Keyword(s):  
Wear Resistance ◽  
Thermal Treatment ◽  
High Velocity ◽  
Composite Coatings ◽  
Research Work ◽  
Wear Intensity ◽  
High Velocity Oxygen Fuel ◽  
Preliminary Thermal Treatment ◽  
Cr Concentration ◽  
Oxygen Fuel

This research work studies the characteristics of wear and wear resistance of composite powder coatings, deposited by high-velocity oxygen fuel, which contain composite mixtures Ni-Cr-B-Si having different chromium concentrations – 9.9%; 13.2%; 14%; 16% and 20% , at one and the same size of the particles and the same content of the remaining elements. The coating of 20% Cr does not contain B and Si. Out of each powder, composite coatings have been prepared without any preliminary thermal treatment of the substrate and with preliminary thermal treatment of the substrate up to 650оС. The coatings have been tested under identical conditions of dry friction over a surface of solid firmly attached abrasive particles using the tribological testing device „Pin-on-disk“. Results have been obtained and the dependences of the hardness, mass wear, intensity of the wearing process, absolute and relative wear resistance on the Cr concentration under identical conditions of friction. It has been found out that for all the coatings the preliminary thermal treatment of the substrate leads to a decrease in the wear intensity. Upon increasing Cr concentration the wear intensity diminishes and it reaches minimal values at 16% Cr. In the case of coatings having 20% Cr concentration, the wear intensity is increased, which is due to the absence of the components B and Si in the composite mixture, whereupon no inter-metallic structures are formed having high hardness and wear resistance. The obtained results have no analogues in the current literature and they have not been published by the authors.

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.

HVOF SPRAYED NANOSTRUCTURED COMPOSITE COATINGS WITH A REDUCED FRICTION COEFFICIENT

Tribologia ◽  
2017 ◽  
pp. 0-0
Author(s):  
Wojciech ŻÓRAWSKI ◽  
Medard MAKRENEK ◽  
Anna GÓRAL ◽  
Sławomir ZIMOWSKI
Keyword(s):  
Composite Structures ◽  
Solid Lubricant ◽  
Continuous Measurement ◽  
Composite Coatings ◽  
Properties Of Coatings ◽  
Nanostructured Composite ◽  
System A ◽  
Mechanical Durability ◽  
The Coefficient Of Friction ◽  
Ball On Disc

Nanostructured materials provide new possibilities, which enable creating composite structures with much better properties than composites obtained from conventional materials. Such a solution facilitates combining selected features of different nanomaterials in order to obtain a composite with the required durability, thermal, insulation, tribological, etc. properties. In the case of a composite containing a solid lubricant, it is comprised of a nanostructured matrix, providing mechanical durability, and an evenly distributed nanostructured solid lubricant. A study of the tribological properties of composite HVOF sprayed from nanostructured WC-12Co mixed with nanostructured Fe3O4, having the properties of the solid lubricant is presented. The coatings were sprayed by means of a Hybrid Diamond Jet system. A T-01 ball on disc tribological tester was used to determine the coefficient of friction on the basis of friction force obtained in the course of continuous measurement at a set load. The result of investigations was compared with properties of coatings sprayed with standard WC-12Co/ Fe3O4.

scholarly journals ASSESSMENT TRIBOLOGICAL PROPERTIES OF COATINGS APPLIED BY HVOF TECHNOLOGY

2013 ◽  
Vol 7 (3) ◽  
pp. 135-139 ◽  
Author(s):  
Janette Brezinová ◽  
Anna Guzanová ◽  
Dagmar Draganovská ◽  
Marián Egri
Keyword(s):  
Room Temperature ◽  
Adhesive Wear ◽  
Thermal Spraying ◽  
Basic Material ◽  
High Velocity Oxygen Fuel ◽  
Properties Of Coatings ◽  
Oxygen Fuel ◽  
Spraying Method

Abstract In this article, the attention is paid to the HVOF (High Velocity Oxygen Fuel) thermal spraying method by which the progressive coatings are applied on basic material C15E (STN 412020). These coatings are based on C-17CO, WC-CO-Cr and Cr3C2-25NiCr. There was made determination of the chemical composition of the coatings and assessment of coatings quality - adhesion, microhardness, porosity and wear resistance at room temperature (21°C) and also at operational elevated temperature (900°C). Results of adhesive wear showed high quality of all evaluated coatings and their suitability to extreme tribological conditions.

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