A New Alternative for Obtaining Nanocrystalline Bioactive Coatings: Study of Hydroxyapatite Deposition Mechanisms by Cold Gas Spraying

Cinca, N.; Vilardell, A.M.; Dosta, S.; Concustell, A.; Cano, I.G.; Guilemany, J.M.; Estradé, S.; Ruiz, Alicia García; Peiró, Francesca

doi:10.1111/jace.14076

Cited by 36 publications

(26 citation statements)

References 36 publications

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“…Rather than VCGS, the use of micrometer sized ceramic particles but with nanoagglomerate structure is highly advantageous in CGS compared to others such as sintered powders since the impact energy may be directly used for compaction rather than neck fracture and grain crushing. As previously reported, E kinetic = E fracture + E thermal, but here the energy necessary to fracture the agglomerated particles is much lower than the corresponding for a sintered particle. This is why, in the present study, coatings up to ~5 mm thick after 10 passes can be reached without delamination.…”

Section: Discussionsupporting

confidence: 60%

“…However, recent research has demonstrated the importance of the microstructure of ceramic particles and, as long as they are not dense, the deposition may be feasible, such as in the case of Hydroxyapatite (HA) . Those studies evaluated the deposition of porous sintered microcrystalline HA powders, showing mechanisms proceeding through pore collapse, fragmentation, and densification as well as grain refinement.…”

Section: Introductionmentioning

confidence: 99%

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Feasibility of using low pressure cold gas spray for the spraying of thick ceramic hydroxyapatite coatings

Vilardell

Cinca

Dosta

et al. 2018

Int J Applied Ceramic Tech

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This article deals with the production of thick ceramic hydroxyapatite coatings obtained by Low Pressure Cold Gas Spray (LPCGS) system. Several factors such as powder microstructure, surface roughness and cold gas spray system are here discussed in the build‐up process. The use of nanocrystalline powder composed by fine agglomerates and needle‐like shape microstructure allows the realignment and compaction of individual crystallites to form thick deposits. In addition, the activation of the substrate surface results convenient for the first impinging particles anchored properly. Then, layer by layer, particles can remain attached leading to coating build‐up. Additionally, the use of low shock pressure as well as constant feeding system provided by LPCGS system lead to homogeneous coatings in comparison with High Pressure Cold Gas Spray (HPCGS) system. The successful coating build‐up has been achieved not only by the use of an agglomerated feedstock powder, but also by previous surface treatment and the use of the low pressure system. The obtaining of HA components by LPCGS is promising within biomedical field. An improvement of component strength is also suggested by means of thermomechanical analysis of the powder. The performance of a post heat‐treatment leads to an increase in HA strength, as well as crystal size.

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Section: Discussionsupporting

confidence: 60%

Section: Introductionmentioning

confidence: 99%

Feasibility of using low pressure cold gas spray for the spraying of thick ceramic hydroxyapatite coatings

Vilardell

Cinca

Dosta

et al. 2018

Int J Applied Ceramic Tech

Self Cite

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“…However, it must not be forgotten that soft agglomerates used here consist of amorphous particles. In case of agglomerates constructed from the crystalline particles, plastic deformation mechanism takes place by slipping or sliding of particles over particles ( Ref 11,12). In case of analyzed here TiO 2 powder, this mechanism is also present.…”

Section: Discussionmentioning

confidence: 90%

“…In the majority of papers showing the possibility of the thick ceramic coatings cold spraying, the agglomeration of the feedstock powder was recognized as being the most important factor for successful coatings fabrication (Ref [6][7][8][9][10][11][12]. Analyzing SEM micrographs of as-synthesized amorphous sol-gel TiO 2 powder (see Fig.…”

Section: Discussionmentioning

confidence: 99%

Low-Temperature Transformation of Amorphous Sol–Gel TiO2 Powder to Anatase During Cold Spray Deposition

2018

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Nanocrystalline TiO 2 coatings were successfully deposited on metallic substrate surfaces through lowpressure cold spray. Sol-gel amorphous TiO 2 dry gel was for the first time used as a feedstock powder. Agglomerated morphology of the amorphous powder with high-density packing of particles and reduced pores number was an important factor for successful low-pressure cold spraying. However, in the present study one more factor contributing to anchoring of TiO 2 particles by cold gas spraying onto a substrate was indicated. This factor enabling effective powder deposition and coating production is based on an exotic for conventional ceramic materials' plastic deformation of amorphous powder. Furthermore, the detailed analysis of SEM, Raman and XRD measurements clearly demonstrated that amorphous titanium dioxide is transformed into crystalline anatase form during the process of low-pressure cold spraying.

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“…The weak liquid-bridge forces liable for the creation of soft agglomerates assist easy fracture upon the impact. Therefore, it is believed that only so-called soft agglomerates are preferred to be sprayed using the LPCS method [40,41]. Soft agglomerates network can be achieved either by adding a suitable binder to the powder [30,32,35] or by using a fresh sol-gel powder [13].…”

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confidence: 99%

Prospects of Low-Pressure Cold Spray for Superhydrophobic Coatings

et al. 2019

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A major challenge in materials engineering is the development of new materials and methods and/or novel combination of existing ones, all fostering innovation. For that reason, this study aims at the synergy between low-pressure cold spray (LPCS) as a tool for coating deposition and sol-gel technique for fabrication of the feedstock powder. The complementarity of both methods is important for the examined topic. On one side, the LPCS being automized and quick mean provides the solid-state of feedstock material in nondestructive conditions and hence the hydrophobicity imparted on the sol-gel route is preserved. On the other side, the sol-gel synthesis enables the production of oxide materials with enhanced deformability due to amorphous form which supports the anchoring while LPCS spraying. In the paper, several aspects including optimal fluoroalkylsilane (FOTS) concentration or substrate roughness are examined initially for altering the superhydrophobicity of produced coatings. Further, it is shown that the appropriate optimization of feedstock powder, being submicron silica matrices covered with two-layer FOTS sheath, may facilitate the anchoring process, support roughening the substrate or cause enhancement the coating hydrophobicity. All the discussion is supported by the characteristics including surface morphology, wettability and thermal behaviour examined by electron microscopy, water contact angle measurements and thermal analysis (TGA/DSC), respectively. The coatings presented in the paper are characterized by an uneven thickness of up to a few silica particles, but final hydrophobicity is provided uniformly on the surface by the formation of multi-level roughness by a detachment of outer layer from the SiO2 particles. Thus, the presented approach constitutes a simple and fast solution for the fabrication of functionalized coatings using LPCS including industrial potential and fundamental research character.

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A New Alternative for Obtaining Nanocrystalline Bioactive Coatings: Study of Hydroxyapatite Deposition Mechanisms by Cold Gas Spraying

Cited by 36 publications

References 36 publications

Feasibility of using low pressure cold gas spray for the spraying of thick ceramic hydroxyapatite coatings

Feasibility of using low pressure cold gas spray for the spraying of thick ceramic hydroxyapatite coatings

Low-Temperature Transformation of Amorphous Sol–Gel TiO2 Powder to Anatase During Cold Spray Deposition

Prospects of Low-Pressure Cold Spray for Superhydrophobic Coatings

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