scholarly journals Optimization and Process Control for High Performance Thermal Spray Coatings

2000 ◽  
Author(s):  
Christian Moreau ◽  
Luc Leblanc
Keyword(s):  
Process Control ◽  
Thermal Spray ◽  
Plasma Spray ◽  
High Performance ◽  
Thermal Spray Coatings ◽  
Wear Resistant Coatings ◽  
Spray Coatings ◽  
Consistent Manner ◽  
The Stability ◽  
Sprayed Coatings

Abstract Thermal spray coatings are used to protect surfaces against exposure to severe conditions. To insure a reliable protection, not only the structure and properties of the sprayed coatings must be optimized but also one needs to develop appropriate process control techniques to produce high performance coatings in a consistent manner, day after day. This is particularly important during plasma spraying as the wear of the electrodes affects significantly the plasma characteristics and consequently the coating properties. First, in this paper, the stability of plasma spray processes is investigated by monitoring in-flight particle characteristics and plasma fluctuations. Secondly, the possibility and advantages of controlling plasma spray processes by monitoring and regulating the condition of the sprayed particles are discussed. Finally, we will see how the properties of thermal barrier coatings and wear resistant coatings can be optimized by controlling the temperature and velocity of the sprayed particles both in the plasma spray and HVOF (high velocity oxy-fuel) processes.

Methods of Determination and Control of Residual Stresses in Plasma Spray Coatings

1997 ◽  
Author(s):  
L. Dekhtyar ◽  
A. Kleyman ◽  
V. Andreychuk ◽  
S. Berman
Keyword(s):  
Residual Stresses ◽  
Thermal Spray ◽  
Plasma Spray ◽  
Thermal Spraying ◽  
Thermal Spray Coatings ◽  
Coating Deposition ◽  
Spray Coatings ◽  
Plasma Spray Coatings ◽  
And Control ◽  
Elastic Characteristics

Abstract Residual stresses exert profound influence on the longevity of parts with thermal spray coatings. The distribution and value of the residual stresses depend on method of coating deposition, composition of the applied material, parameters of thermal spraying and methods of post-treatment. Therefore, the study of the influence of the various technological factors on the residual stresses in the plasma spray coatings is very important. Due to heterogeneity of the coating, residual stresses can be determined only by the experimentation by using new methods which take into consideration real values of elastic characteristics and density of elementary layers. Methods and formulas for the calculations of the residual stresses in coatings deposited on bars, rings, discs, cylinders are presented. Experimental results for the various thermal spray coatings are also shown. These results can be used for the optimization of coating deposition and would supplement the existing database.

Principles and Applications of Thermal Spray Coatings

2021 ◽  
pp. 31-70
Author(s):  
John Henao ◽  
Carlos A. Poblano-Salas ◽  
Fabio Vargas ◽  
Astrid L. Giraldo-Betancur ◽  
Jorge Corona-Castuera ◽  
...  
Keyword(s):  
Thermal Spray ◽  
Thermal Spraying ◽  
Industrial Applications ◽  
Thermal Spray Coatings ◽  
Flame Spray ◽  
Spray Coatings ◽  
Thermal Barriers ◽  
Energy Conversion Devices ◽  
Thermally Sprayed ◽  
Sprayed Coatings

The goal of the chapter is to address the fundamental theory of thermal spraying and its modern industrial applications, in particular, those involving flame spray, HVOF, plasma spray, and cold spray processes. During the last 30 years, thousands of manuscripts and various book chapters have been published in the field of thermal spray, displaying the evolution of thermally sprayed coatings in many industrial applications. Thermal spray coatings are currently interesting for different modern applications including prosthesis, thermal barriers, electrochemical catalysis, electrochemical energy conversion devices, biofouling, and self-repairing surfaces. The chapter will explain the fundamental principles of the aforementioned thermal spraying processes and discuss the effect of different controlling parameters on the final properties of the produced coatings. This chapter will also explore current and future industrial applications of thermal spray coatings.

Slurry Erosion Behavior of Thermal Spray Coatings

2015 ◽  
pp. 268-293
Author(s):  
Harpreet Singh Grewal ◽  
Harpreet Singh
Keyword(s):  
Surface Modification ◽  
Thermal Spray ◽  
Thermal Spray Coatings ◽  
Slurry Erosion ◽  
Erosion Behavior ◽  
Spray Coatings ◽  
Hydro Power Plants ◽  
Surface Modification Techniques ◽  
Sprayed Coatings ◽  
Thermal Sprayed Coatings

Slurry erosion is a degrading phenomenon usually observed in machineries dealing with particle-laden fluid such as hydro power plants, ship propellers, pump impellers, valves, and connecting pipes. The low erosion resistance of commonly employed structural materials prompts the use of different surface modification techniques. Among several types of surface modification techniques, thermal spraying has achieved a significant recognition worldwide due to its versatile nature. In this chapter, slurry erosion behavior of thermal sprayed coatings has been discussed with special emphasis on the contribution of different coating related parameter. It has been observed that microstructure play an important role in determining the slurry erosion performance of thermal spray coatings. Different microstructural features such as splat boundaries, pores, un-melted particles, and cracks are detrimental for the thermal spray coatings exposed to erosive environment. A parameter useful for identification of primary erosion mechanism for thermal sprayed coatings is also discussed.

scholarly journals Wear on Thermal & Plasma Spray Coated Al-2014 Alloy under Dry Sliding Conditions

2019 ◽  
Vol 9 (1) ◽  
pp. 2074-2077
Keyword(s):  
Thermal Spray ◽  
Plasma Spray ◽  
High Velocity ◽  
Fine Particles ◽  
Testing Machine ◽  
Thermal Spray Coatings ◽  
Wear Testing ◽  
Wear Behaviour ◽  
Spray Coatings ◽  
Pin On Disc

In this paper, wear are common problems encountered in the piston. Thermal spray coatings re one of numerous methods for alteration of part's surface properties. The innovation relies upon the standard of dissolving and speeding of fine particles and their quick cementing delayed consequence on the substrate. Among every one of the strategies of thermal spray coatings, High-Velocity Oxy-Fuel and Plasma spray procedure is broadly utilized in different applications. In this research, chemical powder with explicit properties against wear was chosen, and it was showered with high velocity oxygen fuel (HVOF) and plasma spray strategies onto Aluminium 2014 alloy substrates. Both the coatings have same binder with equivalent rate. The coatings were portrayals were done with the help of Scanning Electron Microscope, X-ray Diffractometer, and Pinon-disc wear testing machine. A pin on disc machine was used to analyse the wear behaviour by applying 10N and 20N loads.

Elevated Temperature Erosion Resistance of Several Experimental Amorphous Thermal Spray Coatings

1998 ◽  
Author(s):  
B. Wang
Keyword(s):  
Elevated Temperature ◽  
Thermal Spray ◽  
Erosion Resistance ◽  
Thermal Spray Coatings ◽  
Test Results ◽  
Hvof Coating ◽  
Spray Coatings ◽  
Erosion Test ◽  
Sprayed Coatings ◽  
Better Than

Abstract The elevated temperature erosion resistance of experimental amorphous thermal spray coatings was determined in a laboratory elevated temperature erosion tester. Test conditions attempted to simulate the erosion conditions found at the combustor waterwall tubes in fossil fuel fired boilers. Erosion tests were conducted on four experimental amorphous thermal spray coatings, using the bed ash retrieved from an operating coal fired boiler. An experimental arcspray process was used to spray coatings. These results were compared with erosion test results of two common structural materials, two commercially available arc-sprayed coatings, and a proprietary HVOF coating. Test results indicated that the Duocor coating had the highest erosion resistance among the four experimental coatings, it showed equal resistance to the HVOF coating (DS-200). Compared to AISI 1018 steel, both Duocor and DS-200 coatings reduced material wastage by 26-fold. Other test results indicated that the XJ-16, 60T and Armacor M coatings had equal erosion resistance reducing material wastage approximately 7-fold, while Arrnacor CW reduced by IO-fold. Only slightly better than the unprotected 1018 steel, the X-20 coating performed poorly on erosion tests. The high erosion resistance of Duocor and DS-200 coatings was attributed to their high densities and fine splat structures.

The Development and Implementation of Thermal Spray Coatings for Helicopter Components

1998 ◽  
Author(s):  
R. Guillemette
Keyword(s):  
Fatigue Strength ◽  
Thermal Spray ◽  
High Hardness ◽  
Thermal Spray Coatings ◽  
Fretting Wear ◽  
Wear Testing ◽  
Wear Resistant Coatings ◽  
Spray Coatings ◽  
High Fatigue ◽  
Test Requirements

Abstract Many components in helicopter dynamics systems depend on hard, wear resistant coatings for reliable performance. Component replacement times are currently limited by performance of these coatings in many cases. Thermal spray coatings have been evaluated for these applications to replace nickel and chromium electroplate. The effect of coatings on fatigue strength is quantified by a strain limit concept to reduce test requirements during development phase. Full scale bench testing and coupon wear testing were conducted to reveal large improvement in sliding and fretting wear resistance. A fine porosity network in thermal spray coatings, high hardness and high fatigue strength are shown to be the main contributors to improved wear performance. Thermal spray coatings also exhibited enhanced corrosion resistance in salt fog and crevice corrosion conditions. These data permitted implementation on several critical helicopter components.

In-Situ Observation and Ae Analysis of Microscopic Fracture Process of Thermal Spray Coatings

1998 ◽  
Author(s):  
K. Akita ◽  
G. Zhang ◽  
S. Takahashi ◽  
H. Misawa ◽  
S. Tobe
Keyword(s):  
Thermal Spray ◽  
Bonding Strength ◽  
Thermal Spray Coatings ◽  
Fracture Mechanisms ◽  
In Situ Observation ◽  
Spray Coatings ◽  
Thermally Sprayed Coatings ◽  
Thermally Sprayed ◽  
Sprayed Coatings

Abstract Microscopic fracture mechanisms of thermal spray coatings under bending stress are investigated. Samples of thermally sprayed coatings were made using three distances. The sprayed powder was pure molybdenum. Vertical microcracks occur in lamellae and subsequently, these cracks join together and form vertical macrocracks in the samples sprayed with a short spraying distance. On the other hand, horizontal microcracks occur at the lamellae interfaces, and these cracks link together in the samples sprayed with a long spraying distance. These tendencies can be explained in terms of the hardness of the lamella and the bonding strength between each lamella. It is clarified that the bonding strength between each lamella corresponds to the applied strain at the point of rapid increase of the AE event count. The amplitude and rate of AE beyond the point of rapid increase are high in the coatings which formed macrocracks. It is concluded that the coating which has high resistance to crack formation has a high point of AE increase, low AE amplitude and low AE increasing rate.

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