USE OF IBA TECHNIQUES TO CHARACTERIZE HIGH VELOCITY THERMAL SPRAY COATINGS

2001 ◽  
Vol 15 (28n29) ◽  
pp. 1428-1436 ◽  
Author(s):  
W. TROMPETTER ◽  
A. MARKWITZ ◽  
M. HYLAND
Keyword(s):  
Thermal Spray ◽  
High Velocity ◽  
Sliding Wear ◽  
Thermal Spraying ◽  
Thermal Spray Coatings ◽  
Spray Coatings ◽  
The Past ◽  
Composition And Structure ◽  
Wide Range ◽  
Sprayed Coating

Spray coatings are being used in an increasingly wide range of industries to improve the abrasive, erosive and sliding wear of machine components. Over the past decade industries have moved to the application of supersonic high velocity thermal spray techniques. These coating techniques produce superior coating quality in comparison to other traditional techniques such as plasma spraying. To date the knowledge of the bonding processes and the structure of the particles within thermal spray coatings is very subjective. The aim of this research is to improve our understanding of these materials through the use of IBA techniques in conjunction with other materials analysis techniques. Samples were prepared by spraying a widely used commercial NiCr powder onto substrates using a HVAF (high velocity air fuel) thermal spraying technique. Detailed analysis of the composition and structure of the power particles revealed two distinct types of particles. The majority was NiCr particles with a significant minority of particles composing of SiO 2/ CrO 3. When the particles were investigated both as raw powder and in the sprayed coating, it was surprising to find that the composition of the coating meterial remained unchanged during the coating process despite the high velocity application.

The Comparison Study on Abrasive and Erosive Resistance Properties of Thermal Spray Coatings

2020 ◽  
Vol 901 ◽  
pp. 49-54
Author(s):  
Jirasak Tharajak ◽  
Noppakun Sanpo
Keyword(s):  
Thermal Spray ◽  
Thermal Spraying ◽  
Spray Coating ◽  
Solid Material ◽  
Thermal Spray Coating ◽  
Comparison Study ◽  
Spray Coatings ◽  
Wide Range ◽  
Resistance To Wear ◽  
Sprayed Coating

Thermal spraying is a technology which improves and restores the surface of a solid material. The process can be used to apply coatings to a wide range of materials and components, in order to provide resistance to wear, erosion, cavitation, corrosion, abrasion or heat. In this paper, the study of abrasive and erosive properties of Cr3C2/20%NiCr and FeCrB + Al thermal sprayed coating samples were focused. It was revealed that both received thermal spray coating samples show outstanding abrasive and erosive resistance properties.

scholarly journals Sliding Wear of Conventional and Suspension Sprayed Nanocomposite WC-Co Coatings: An Invited Review

2021 ◽  
Author(s):  
R. Ahmed ◽  
O. Ali ◽  
C. C. Berndt ◽  
A. Fardan
Keyword(s):  
Wear Rate ◽  
Thermal Spray ◽  
Sliding Wear ◽  
Failure Modes ◽  
Thermal Spray Coatings ◽  
Annual Growth Rate ◽  
Total Energy Consumption ◽  
Wear Performance ◽  
Wear Rates ◽  
Spray Coatings

AbstractThe global thermal spray coatings market was valued at USD 10.1 billion in 2019 and is expected to grow at a compound annual growth rate of 3.9% from 2020 to 2027. Carbide coatings form an essential segment of this market and provide cost-effective and environmental friendly tribological solutions for applications in aerospace, industrial gas turbine, automotive, printing, oil and gas, steel, and pulp and paper industries. Almost 23% of the world’s total energy consumption originates from tribological contacts. Thermal spray WC-Co coatings provide excellent wear resistance for industrial applications in sliding and rolling contacts. Some of these applications in abrasive, sliding and erosive conditions include sink rolls in zinc pots, conveyor screws, pump housings, impeller shafts, aircraft flap tracks, cam followers and expansion joints. These coatings are considered as a replacement of the hazardous chrome plating for tribological applications. The microstructure of thermal spray coatings is however complex, and the wear mechanisms and wear rates vary significantly when compared to cemented WC-Co carbides or vapour deposition WC coatings. This paper provides an expert review of the tribological considerations that dictate the sliding wear performance of thermal spray WC-Co coatings. Structure–property relationships and failure modes are discussed to grasp the design aspects of WC-Co coatings for tribological applications. Recent developments of suspension sprayed nanocomposite coatings are compared with conventional coatings in terms of performance and failure mechanisms. The dependency of coating microstructure, binder material, carbide size, fracture toughness, post-treatment and hardness on sliding wear performance and test methodology is discussed. Semiempirical mathematical models of wear rate related to the influence of tribological test conditions and coating characteristics are analysed for sliding contacts. Finally, advances for numerical modelling of sliding wear rate are discussed.

Comprehensive Methods for Studying Microinhomogeneity in Thermal Spray Coatings with Amorphous-Crystalline Structure

1998 ◽  
Author(s):  
G. Grigorenko ◽  
A. Borisova
Keyword(s):  
Thermal Spray ◽  
Crystalline Structure ◽  
Structural Phase ◽  
Thermal Spraying ◽  
Integrated Approach ◽  
Thermal Spray Coatings ◽  
Chemical Heterogeneity ◽  
New Approach ◽  
X Ray ◽  
Spray Coatings

Abstract An integrated approach was developed for investigation of thermal spray coatings with the amorphous-crystalline structure. The new approach combines methods of metallography, differential thermal and X-ray phase analysis, scanning electron microscopy and X-ray microanalysis. This makes it possible to reveal structural, phase and chemical heterogeneity, determine the degree of amorphization of coatings, temperature and heat of crystallization of the amorphous phase during heating. The new integrated approach was used to study amorphous-crystalline coatings of the Ni-P, Fe-Ni-B and Fe-B systems produced by thermal spraying.

scholarly journals Combating Wear of ASTM A36 Steel by Surface Modification Using Thermally Sprayed Cermet Coatings

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Vineet Shibe ◽  
Vikas Chawla
Keyword(s):  
Thermal Spray ◽  
Sliding Wear ◽  
Thermal Spray Coatings ◽  
Wear Performance ◽  
Cermet Coatings ◽  
Spray Coatings ◽  
Spray Technique ◽  
A36 Steel ◽  
Thermally Sprayed ◽  
Better Than

Thermal spray coatings can be applied economically on machine parts to enhance their requisite surface properties like wear, corrosion, erosion resistance, and so forth. Detonation gun (D-Gun) thermal spray coatings can be applied on the surface of carbon steels to improve their wear resistance. In the present study, alloy powder cermet coatings WC-12% Co and Cr3C2-25% NiCr have been deposited on ASTM A36 steel with D-Gun thermal spray technique. Sliding wear behavior of uncoated ASTM A36 steel and D-Gun sprayed WC-12% Co and Cr3C2-25% NiCr coatings on base material is observed on a Pin-On-Disc Wear Tester. Sliding wear performance of WC-12% Co coating is found to be better than the Cr3C2-25% NiCr coating. Wear performance of both these cermet coatings is found to be better than uncoated ASTM A36 steel. Thermally sprayed WC-12% Co and Cr3C2-25% NiCr cermet coatings using D-Gun thermal spray technique is found to be very useful in improving the sliding wear resistance of ASTM A36 steel.

Image-Based Modeling for Assessing Thermal Conductivity of Thermal Spray Coatings at Ambient and High Temperature

2006 ◽  
Author(s):  
Y. Tan ◽  
A. Sharma ◽  
J. P. Longtin ◽  
S. Sampath ◽  
H. Wang
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
Thermal Spray ◽  
Process Parameters ◽  
Thermal Spraying ◽  
Thermal Spray Coatings ◽  
Analysis Model ◽  
Element Analysis ◽  
Spray Coatings ◽  
Coating Microstructure

Thermal spray coatings are used extensively for protection of engineering components and structures in a variety of applications. Due to the nature of thermal spraying process, the coating thermal, mechanical, and electrical properties depend strongly on the coating microstructure, which consists of many individual splats, interfaces between the splats, defects and voids. The coating microstructure, in turn, is determined by the thermal spray process parameters. In order to relate coating process parameters to the final coating performance, then, it is desirable to relate coating microstructure to coating properties. In this work, thermal conductivity is used as the physical parameter of interest. Thermal conductivity of thermal spray coatings is studied by using an image analysis-based approach of typical coating cross sections. Three coating systems, yttria stabilized zirconia (YSZ), molybdenum, and Ni-5wt.%Al are explored in this work. For each material, thermal conductivity is simulated by using a microstructure image-based finite element analysis model. The model is then applied to high temperature conditions (up to 1200 °C) with a hot stage-equipped scanning electron microscope imaging technique to assess thermal conductivity at high temperatures. The coating thermal conductivity of metallic coatings is also experimentally measured by using a high-temperature laser flash technique.

Abrasion-Corrosion of Thermal Spray Coatings

2015 ◽  
pp. 88-120 ◽  
Author(s):  
Robert J. K. Wood ◽  
Mandar R. Thakare
Keyword(s):  
Thermal Spray ◽  
Applied Load ◽  
Thermal Spray Coatings ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Wear Rates ◽  
Spray Coatings ◽  
Drilling Tools ◽  
Wide Range ◽  
Aqueous Environments

WC-based thermal-spray and High Velocity Oxy-Fuel (HVOF) coatings are extensively used in a wide range of applications ranging from downhole drilling tools to gas turbine engines. WC-based thermal spray coatings offer improved wear resistance as a result of hard phases dispersed in binder-rich regions. However, the presence of hard and soft phases within the coating can also lead to the formation of micro-galvanic couplings in aqueous environments leading to some reduction in combined wear-corrosion resistance. Furthermore, the coating also responds differently to change in mechanical loading conditions. This chapter examines the wear-corrosion performance of thermal spray coatings in a range of wear, electrochemical, and wear-corrosion tests under varying contact conditions to develop models and establish relationships between wear mechanisms, wear rates, and environmental factors such as pH and applied load.

Thermal and Cold Spray: Recent Developments

2008 ◽  
Vol 384 ◽  
pp. 1-59 ◽  
Author(s):  
Pierre Fauchais ◽  
Ghislain Montavon
Keyword(s):  
Thermal Spray ◽  
High Reliability ◽  
Small Diameter ◽  
Thermal Spraying ◽  
Melting Behavior ◽  
Decomposition Temperature ◽  
The Past ◽  
Wide Range ◽  
Powder Particles ◽  
Average Size

Thermal spraying consists in a technology aiming at producing coatings whose thicknesses range from 10 μm to a few millimeters onto mechanical components to confer them specific and unique functional properties, such as wear and corrosion resistances, friction coefficient adaptation, thermal and electrical insulation, biocompatibility, repair, etc., among the principals. Thermal spraying consists in injecting in a viscous enthalpic jet (animated by a momentum) powder with particles which average size ranges from 0.01 to 100 μm. These particles are melted and simultaneously accelerated towards the surface of the part to be covered. They form, after impact, spreading and solidification, near-circular lamellae the stacking of which form the coating. Due to the versatility of the available processes exhibiting a wide range of enthalpic and momentum contents, virtually any kind of material exhibiting congruent melting behavior can be processed, from alloys and ceramics to polymers, ever since its melting temperature differs from its vaporization or decomposition temperature by at least 300 K and that it can be processed previously under the form of powder particles or wires. Thermal spray techniques offer the unique capability to manufacture a large variety of coatings on components of a large variety and geometry. However, thermal spraying constitutes a special process for which the coating service properties derive mostly from the structure and indirectly from the selection of the operating parameters. Very significant improvements over the past years permitted to diagnose the in-flight particle characteristics, mostly in terms of velocity and temperature. Recently, these new capabilities have made possible the development of on-line process controls. This should participate to a drastic increase in coating reliability. In convetntional thermal spraying processes, a pulverulent feedstock (i.e., powder particles) is injected within the plasma jet via a carrier gas. This approach does not permit to process small diameter particles; i.e., nano-sized particles, which could permit to form finely grained coatings. Replacing gas by liquid to carry particles offer the unique possibility to process nano-sized particles. Cold gas spraying may appear as an alternative process to reach the same goal. Indeed, thermal spray processes experienced very significant developments over the past years, opening new doors to manufacture coatings with a high reliability and superior properties. This papepr indend at presenting some of those developments.

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