Development and implementation of plasma sprayed nanostructured ceramic coatings

Gell, Maurice; Jordan, Eric H.; Sohn, Yong Ho; Goberman, Daniel; Shaw, Leon L.; Xiao, T. D.

doi:10.1016/s0257-8972(01)01470-0

Cited by 283 publications

(180 citation statements)

References 14 publications

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“…11 and 16)a r e uniformly spread throughout the coating microstructure, acting as crack arresters, toughening the coating. Such a toughening mechanism was suggested by references [9,10,24,25] in a study of mechanical properties of nanostructured related ceramic thermal spray coatings.…”

Section: Hardness Crack Propagation Resistance and Coating Isotropymentioning

confidence: 81%

“…These characteristics open interesting possibilities in thermal spray. Indeed, it has already been shown that nanostructured thermal spray ceramic oxide coatings, like Al 2 O 3 -TiO 2 and TiO 2 , can have a superior wear performance when compared to similar coatings produced from conventional ceramic oxide pow- ders [9][10][11]. However, in other cases, authors have not observed this same improvement in the wear behavior when using nanostructured feedstocks [12].…”

Section: Introductionmentioning

confidence: 99%

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From APS to HVOF spraying of conventional and nanostructured titania feedstock powders: a study on the enhancement of the mechanical properties

Lima

Marple

2006

Surface and Coatings Technology

115

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From APS to HVOF spraying of conventional and nanostructured titania feedstock powders : A study on the enhancement of the mechanical properties Lima, R. S.; Marple, B. R. Abstract Nanostructured and conventional titania (TiO 2 ) feedstocks were thermal sprayed using air plasma spray (APS) and high-velocity oxy-fuel (HVOF). The HVOF-sprayed coatings made from the nanostructured feedstock exhibited superior abrasion resistance, bond strength and crack propagation resistance when compared to the coatings made from the conventional feedstocks sprayed using HVOF and APS. The enhancement of the mechanical properties was due to (i) the processing (HVOF) and (ii) the nanocharacter of the feedstock. It was found that the HVOF-sprayed coating made from the nanostructured feedstock exhibited isotropic characteristics and microstructure with tiny zones of agglomerated nanostructured particles randomly spread throughout the coating structure. It was observed that these nanostructured zones acted as crack arresters by blunting and branching crack tips, enhancing the crack propagation resistance of the coating. Due to the isotropic characteristics of mechanical properties, the HVOF-sprayed coating made from the nanostructured feedstock exhibited uniform crack propagation under Vickers indentation, i.e., four cracks emanating from the corners of the Vickers indentation impression. D

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Section: Hardness Crack Propagation Resistance and Coating Isotropymentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

From APS to HVOF spraying of conventional and nanostructured titania feedstock powders: a study on the enhancement of the mechanical properties

Lima

Marple

2006

Surface and Coatings Technology

115

View full text Add to dashboard Cite

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“…This method allows the deposition of nanostructured layers with better properties than their conventional counterparts [1][2][3][4][5]. Still, the nanoparticles need to be previously agglomerated into a sprayable powder, as they can not be directly fed into the plasma torch [6][7][8]. This agglomeration process is usually done by using spray-drying [6][7][8][9][10][11] or freezedrying [11] from a nanoparticle suspension, frequently followed by a thermal treatment in order to decrease the granule porosity [6,8].…”

Section: Introductionmentioning

confidence: 99%

“…Still, the nanoparticles need to be previously agglomerated into a sprayable powder, as they can not be directly fed into the plasma torch [6][7][8]. This agglomeration process is usually done by using spray-drying [6][7][8][9][10][11] or freezedrying [11] from a nanoparticle suspension, frequently followed by a thermal treatment in order to decrease the granule porosity [6,8]. The quality of the feedstock depends on the characteristics of the initial nanosuspension, which should present high solid content, low viscosity and high stability.…”

Section: Introductionmentioning

confidence: 99%

Influence of the feedstock characteristics on the microstructure and properties of Al2O3–TiO2 plasma-sprayed coatings

Vicent

Bannier

Benavente

et al. 2013

Surface and Coatings Technology

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Atmospheric plasma spraying (APS) is an interesting technique to obtain nanostructured coatings due to its versatility, simplicity and relatively low cost. However, nanometric powders can not be fed into the plume using conventional feeding systems, due to their low mass and poor flowability, and must be adequately reconstituted into sprayable micrometric agglomerates.In this work, Al 2 O 3 -13wt%TiO 2 nanostructured and submicron-nanostructured powders were deposited using APS. The feedstocks were obtained by spray drying from two starting suspensions, prepared by mixing two commercial nanosuspensions of Al 2 O 3 and TiO 2 , or by adding nanosized TiO 2 and submicron-sized Al 2 O 3 powders to water. The spray-dried granules were heat-treated to reduce their porosity and the resultant powders were fully characterised.Optimisation of the deposition conditions enabled the reconstituted powders to be successfully deposited, yielding coatings that were well bonded to the substrate. The coating microstructure, characterised by SEM, was formed by semi-molten feedstock agglomerates surrounded by fully molten particles that act as a binder.Moreover, microhardness, adhesion, and tribological behaviour were determined, and the impact of the granule characteristics on these properties was studied. It was found that changing the feedstock characteristics allows to control the coating quality and properties.2

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“…Microcracks and micropores around partially melted and unmelted particles of the initial material were detected on the thin section of the coating sample obtained from the nanoagglomerate powder. This type of microstructure was also described in [4,10,11]. The porosity of the coating was measured.…”

Section: Resultsmentioning

confidence: 95%

Investigation of deformation behavior and fracture of ceramic coatings by the acoustic emission method

Klyatskina

Salvador

Segovia

et al. 2017

J. Mach. Manuf. Reliab.

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Abstract-The use of protective coatings on components of machines and mechanisms provides the greatest economic benefit at the lowest additional cost. Plasma spraying is one of the most productive, technologically advanced, and efficient methods of producing these coatings. The results of investigations of structures, mechanical properties, and fracture surfaces of ceramic wear resistant coatings produced by plasma spraying have been presented. DOI: 10.3103/S1052618817020078Intensive economic development and its efficiency increase are largely determined by the use of new technological processes. Advanced technologies based on major basic studies (laser, plasma, and powder metallurgy, self-propagating high-temperature synthesis, etc.) make a significant contribution to the development of special engineering.It is impossible to produce machinery and equipment for operation under extreme conditions (large dynamic loads, aggressive media, erosive and abrasive wear, etc.) is impossible without using special coatings. Special coatings are used to save high-alloy materials and to harden surfaces in order to give them special properties, such as protection from exposure to high temperatures, thermal erosion wear, neutron fluxes and radio emissions, abrasive wear, and the restoration of the geometric dimensions of the surface of worn-out details [12].The protective coating material is determined based on the conditions of its use. In the case of oxidecontaining materials (ZrO 2 -Y 2 O 3 and Al 2 O 3 -TiO 2 ), one of the main limiting factors of their use is low plasticity, as a result of which they fracture (due to cracking, delamination, or loss of material) [3].Coating strength is an important characteristic that determines the performance of products. Low strength can be caused by the physical nature of the coating structure consisting of separate relatively weakly bound particles and layers, porosities, and lack of volume coupling during the formation. Cohesive and adhesive strengths of welding regions is low as a consequence of defects in their structure. In addition, low adhesive strength is often caused by the difference in types of connections between the base material and the coating.In view of the above-mentioned, a need arises for standard special tests for the evaluation of the mechanical properties of ceramic coatings. One such method would be to use acoustic emission together with bending tests to investigate the phenomenon of the emergence of sound waves during the deformation of solids. Acoustic emissions are associated with the radiation of stress waves generated in the solid during deformation as result of discrete dynamic processes, such as the occurrence of macro-and microcracks during operation, which, as is known, are accompanied by the release of energy [4,5]. This method makes it possible to investigate the mechanisms of the fracture of materials, namely, the high sensitivity of the acoustic emission method makes it possible to determine the defectology type, which includes the size and number of...

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Development and implementation of plasma sprayed nanostructured ceramic coatings

Cited by 283 publications

References 14 publications

From APS to HVOF spraying of conventional and nanostructured titania feedstock powders: a study on the enhancement of the mechanical properties

From APS to HVOF spraying of conventional and nanostructured titania feedstock powders: a study on the enhancement of the mechanical properties

Influence of the feedstock characteristics on the microstructure and properties of Al2O3–TiO2 plasma-sprayed coatings

Investigation of deformation behavior and fracture of ceramic coatings by the acoustic emission method

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