scholarly journals Advanced Functional Metal-Ceramic and Ceramic Coatings Deposited by Low-Pressure Cold Spraying: A Review

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1044
Author(s):  
Marcin Winnicki

Based on the recent analysis of various databases, cold spray (CS), the newest method among thermal spraying technologies, has received the unabated attention of hundreds of researchers continuously since its invention in the 1980s. The significance of CS lies in the low process temperature, which usually ensures compressive residual stresses and allows for the formation of coatings on a thermally sensitive substrate. This paper concerns the low-pressure cold spray (LPCS) variant employed for forming metal matrix composites (MMCs) with high ceramic contents and all-ceramic coatings. At the very beginning, the influence of LPCS process parameters on deposition efficiency (DE) is analysed. In the next part, the most useful feedstock powder preparation techniques for LCPS are presented. Due to the combination of bottom-up powder production methods (e.g., sol-gel (SG)) with LCPS, the metal matrix that works as a binder for ceramic particles in MMC coatings can be removed, resulting in all-ceramic coatings. Furthermore, with optimization of spraying parameters, it is possible to predict and control phase transformation in the feedstock material. Further in the paper, differences in the bonding mechanism of metal–ceramic mixtures and ceramic particles are presented. The properties and applications of various MMC and ceramic coatings are also discussed. Finally, the exemplary direction of CS development is suggested.

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 829 ◽  
Author(s):  
Anna Gibas ◽  
Agnieszka Baszczuk ◽  
Marek Jasiorski ◽  
Marcin Winnicki

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.


2020 ◽  
pp. 2-11
Author(s):  
N. V. TITOV ◽  
◽  
A. V. KOLOMEYCHENKO ◽  
V. L. BASINYUK ◽  
I. N. KRAVCHENKO ◽  
...  

Author(s):  
Seremak Wioletta ◽  
Baszczuk Agnieszka ◽  
Jasiorski Marek ◽  
Gibas Anna ◽  
Winnicki Marcin

AbstractThis work shows that the titanium dioxide coatings obtained by low-pressure cold gas spraying with the use of the sol–gel amorphous TiO2 powder are characterized by photocatalytic activity despite their partial amorphous content. Moreover, the research outcome suggests that the decomposition rate of organic pollutants is enhanced after long-term exposure to moisture. The condensation humidity test is not detrimental to the continuity and integrity of the coating, but the phase composition of coatings changes—with the exposure to water vapor, the portion of the amorphous phase crystallizes into brookite. The mechanism responsible for the conversion of amorphous TiO2 into brookite is attributed to the water-driven dissolution and reprecipitation of TiO6 octahedra. It has been shown that an additional parameter necessary for the stabilization of the brookite is the oxygen depletion of the amorphous structure of titanium dioxide. Considering the results presented in this paper and the advantages of a portable, low-pressure cold spray system for industrial applications, it is expected that TiO2 coatings produced from a sol–gel feedstock powder can be further developed and tested as efficient photocatalysts.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Erik Poloni ◽  
Florian Bouville ◽  
Christopher H. Dreimol ◽  
Tobias P. Niebel ◽  
Thomas Weber ◽  
...  

AbstractThe brick-and-mortar architecture of biological nacre has inspired the development of synthetic composites with enhanced fracture toughness and multiple functionalities. While the use of metals as the “mortar” phase is an attractive option to maximize fracture toughness of bulk composites, non-mechanical functionalities potentially enabled by the presence of a metal in the structure remain relatively limited and unexplored. Using iron as the mortar phase, we develop and investigate nacre-like composites with high fracture toughness and stiffness combined with unique magnetic, electrical and thermal functionalities. Such metal-ceramic composites are prepared through the sol–gel deposition of iron-based coatings on alumina platelets and the magnetically-driven assembly of the pre-coated platelets into nacre-like architectures, followed by pressure-assisted densification at 1450 °C. With the help of state-of-the-art characterization techniques, we show that this processing route leads to lightweight inorganic structures that display outstanding fracture resistance, show noticeable magnetization and are amenable to fast induction heating. Materials with this set of properties might find use in transport, aerospace and robotic applications that require weight minimization combined with magnetic, electrical or thermal functionalities.


1998 ◽  
Vol 13 (4) ◽  
pp. 803-811 ◽  
Author(s):  
Philippe Colomban

The problems encountered to tailor simultaneously various specific chemical or physical properties are discussed. Selected polymeric precursors used in association with fine powders allow the control of the nano/microstructure of composites and hence the preparation of functional (FGM) and hierarchical reinforced (HRC) composites, making it possible to combine several kinds of fibers, interphases, and matrices in the same composite (hot microwave absorbent), to control the fiber/matrix interface (long life times composites), to achieve net-shape sintering of 3D composite matrices, and to prepare thick films of metal-ceramic composites with tailored microwave absorption (radar stealthiness).


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