The effect of post-treatments on the powder morphology of titanium dioxide (TiO2) powders synthesized for cold spray

Salim, N. Tjitra; Yamada, Motohiro; Nakano, Hiromi; Shima, Koichiro; Isago, Hiroaki; Fukumoto, Masahiro

doi:10.1016/j.surfcoat.2011.07.030

Cited by 33 publications

(24 citation statements)

References 18 publications

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“…However, only a slight increase of crystallinity and crystallite sizes were observed for the powders calcined at 200 C, 300 C and 400 C. These results are in good agreement with previous reported studies which shows that only small changes in the crystallinity and the crystallite sizes of the TiO 2 powders were observed when the powders were calcined below 500 C 3,15) . Moreover, the XRD results were consistent with the DTA result as the curve also revealed that no temperature-induced phase transition occurred when the temperature was increased up to 400 C. Despite the fact that the transformation of anatase to rutile is above 700 C 12,15,16) and only anatase phase was identi ed even after the post-heat treatment. Figure 3 shows the XPS spectra of the synthesized TiO 2 powders.…”

Section: Resultssupporting

confidence: 81%

“…3(d). This result indicates that the presence of SO 4 2− ions reduced as the calcination temperature increased to 400 C. The SO 4 2− ions, which originated from the precursor, were also reported after annealing at 600 C 12,16,22) . Sathyamoorthy et al 23) reported that the sulfate ions detached from the surface of anatase TiO 2 particles only when the powder was calcined at 650 C. The removal of the sulfate ions was via the liberation of highly acidic sulfur trioxide fumes.…”

Section: Resultsmentioning

confidence: 68%

“…Moreover, J. Huang et al 17) reported that the peak that is located with this particular binding energy could be attributed to adsorbed oxygen which in turn is attributed to lattice distortion and porous structure. Meanwhile, N. T Salim et al 12) and A. Di Paola et al 16) reported that this peak might also correspond to the sulfate (SO 4 2− ) bonding.…”

Section: Resultsmentioning

confidence: 98%

“…The change in crystal structure and crystallite size is not favorable as it reduces the photocatalytic property of the coatings 9) . A lower temperature process, such as cold spraying, offers a great advantage in the deposition process as this process generally operates below the melting temperature of the feedstock materials 8,[10][11][12][13] . Thus, this technique can prevent phase changes after the coating process.…”

Section: Introductionmentioning

confidence: 99%

“…A cold-sprayed coating with 150 µm thickness was fabricated using agglomerated TiO 2 powders synthesized with addition of ammonium sulfate and hydrothermally treated prior to the coating process 12) . The NH 4 + and SO 4 2− ions adsorptions on surface of TiO 2 and post hydrothermal treatment have contributed to the formation of an oriented agglomerated structure in a single crystal axis were believed as the factors that lead to the building-up of the coating.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Powder Calcination on the Cold Spray Titanium Dioxide Coating

et al. 2016

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The agglomeration of nanoparticles is usually undesirable in the formation of powder. However, a coating process using the cold spray method only allows the usage of micrometer-sized feedstock powder in a regular powder feeder. In this study, TiO 2 coatings on ceramic tiles were prepared by a cold spray process using agglomerated TiO 2 powders synthesized via a simple hydrolysis method. XRD analysis showed that TiO 2 powders, composed of anatase phase and calcination at 200 C to 400 C, resulted in enhanced crystallinity and crystallite size of the anatase TiO 2 powders. SEM micrographs revealed that the obtained powders were in spherical-like agglomerates with the tertiary particles having diameters of 5-20 µm. TEM image revealed that the obtained TiO 2 powders were composed of nanometer primary particles. XPS analyses showed that TiO 2 powders without calcination and calcined at different temperatures were formed through the Ti-O bonds. The in uences of post treatment at low calcination temperatures of the as-synthesized TiO 2 powders were studied on powder deposition. The results of this study indicated that a post treatment on TiO 2 powder improved powder deposition on ceramic tile substrate via the cold spray method. The cross-section of the obtained coating which was observed using SEM showed that nanoparticles TiO 2 powders in the agglomerated form were able to be deposited on the substrate and formed a thick coating. A stacking of agglomerated TiO 2 powders was found on the cross-section observation which is due to the breaking up of ceramic particles which was induced by porosity in the powder and is believed to be responsible for the formation of the coating.

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Section: Resultssupporting

confidence: 81%

Section: Resultsmentioning

confidence: 68%

Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Powder Calcination on the Cold Spray Titanium Dioxide Coating

et al. 2016

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Mechanical characterization of low‐pressure cold‐sprayed metal coatings on aluminium

Astarita

Durante

Langella

et al. 2013

Surface & Interface Analysis

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Metal coatings are widely used in order to improve the superficial properties of mechanical components or tools. Cold spray deposition is an attractive technology that allows to realize a reported coating on a metallic or polymeric surface. The essence of the phenomenon is that particles of ductile metals or alloys, having diameter of approximately 10-100 micron, become deformed and strongly attached to a surface when they impinge on the surface of metals, ceramics or glasses at impact velocities in the range of about 400-1200 m/s. In this manner, coatings can be formed on a substrate. In this work, mechanical tests were carried out in order to evaluate the adhesion of different metal particles on an aluminium alloy substrate, in order to characterize both the coating-substrate adhesion and the adhesion between two consecutive layers of the cold-sprayed metal coating. In particular, both bending tests and pure adhesion test were carried out in order to better understand the powder deposition mechanism. Bending tests were carried out in four-point bending configuration. On the basis of the experimental campaign, it results that the adhesion of the pure aluminum particles are very good, conversely the copper particles show a good adhesion on the aluminum substrate but have a low internal cohesion.

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