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.

Formation of Thermally Sprayed Coatings on Grid-Like Structure Substrate

2016 ◽  
Vol 258 ◽  
pp. 387-390 ◽  
Author(s):  
David Jech ◽  
Ladislav Čelko ◽  
Lenka Klakurková ◽  
Karel Slámečka ◽  
Miroslava Horynová ◽  
...  
Keyword(s):  
Thermal Spray ◽  
Energy Dispersive Spectrometer ◽  
Atmospheric Plasma ◽  
Spray Coatings ◽  
Substrate Structure ◽  
Thermally Sprayed Coatings ◽  
Shadowing Effect ◽  
Ysz Coating ◽  
Thermally Sprayed ◽  
Sprayed Coatings

The main goal of this contribution is to investigate the influence of the substrate morphology on the resulting thermally sprayed coatings microstructure. Therefore, three different representative coating systems and/or thermal spray techniques were utilized to produce the coatings on grid-like structure substrates: (i) CoNiCrAlY bond coat (BC) sprayed by high velocity oxygen fuel (HVOF) technique and yttria stabilized zirconia (YSZ) top coat (TC) sprayed by means of atmospheric plasma spray (APS) technique, (ii) YSZ coating sprayed by means of APS and (iii) YSZ coating sprayed by means of nanoparticle colloid suspension plasma spraying (SPS). The shadowing effect of thermal spray coatings in relation with the grid-like substrate structure was investigated in detail. Resulting microstructure of sprayed samples was studied utilizing light microscopy, digital image analysis, scanning electron microscopy, energy-dispersive spectrometer and X-ray diffraction techniques.

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.

In-situ observation of crack propagation in thermally sprayed coatings

2010 ◽  
Vol 205 (7) ◽  
pp. 1807-1811 ◽  
Author(s):  
Radek Mušálek ◽  
Ondřej Kovářík ◽  
Jiří Matějíček
Keyword(s):  
Crack Propagation ◽  
In Situ Observation ◽  
Thermally Sprayed Coatings ◽  
Thermally Sprayed ◽  
Sprayed Coatings

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.

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.

Bonding strength of thermally sprayed coatings

2002 ◽  
Vol 16 (8) ◽  
pp. 654-658
Author(s):  
S V Zakharov ◽  
A N Serenko ◽  
V A Royanov
Keyword(s):  
Bonding Strength ◽  
Thermally Sprayed Coatings ◽  
Thermally Sprayed ◽  
Sprayed Coatings
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