Nanocomposite coatings: thermal spray processing, microstructure and performance

Abstract

The processing of nanomaterials and nanocomposites has advanced since the 1990s. The growth and opportunities afforded by this technological domain is evident through the trends of research and development (R&D) funding, Science Citation Index (SCI) publications, and patent applications presented in this paper. This article reviews the current state for the development of thermal sprayed nanocomposite coatings. The types of nanocomposite thermal spray feedstock materials that are available commercially, as well as those currently in the development phase, are critically assessed. The thermal spray approaches to deposit nanocomposite coatings are discussed, including the conventional plasma spray and high velocity oxygen fuel (HVOF) processes and the more recently developed cold spray, suspension thermal spray (STS), and solution precursor thermal spray (SPTS) processes. These processes are assessed in relation to their deposition mechanisms and the specific nanocomposite materials associated with each technique. The unique microstructure of the coatings deposited by each method is highlighted in relation to process and compositional control. The exceptional attributes of nanocomposite coatings, such as mechanical strength and toughness, wear resistance, thermophysical, and electrical properties, are also presented together with specific applications.

A Review of Advanced Composite and Nanostructured Coatings by Solid-State Cold Spraying Process

“…One typical example is nanostructured WC-Co coatings. Though the CS of micro-sized WC-Co coatings showed poor deposition efficiency than that by HVOF, 244 the use of nanostructured feedstock significantly improves the deposition efficiency and density of CS coatings. This is possibly because the critical velocity is lowered and there is a higher surface area for contact between the binder phase and hard ceramic particles for effective deposition of nanostructured particles.…”

“…The low porosity, absence of cracks, indistinguishable particle interfaces, and absence of spallation and delamination indicated that the CS nanostructured coatings may demonstrate good cohesion and adhesion. 244 Ajdelsztajn et al 144 nm. Elongated grains were also observed due to high velocity impact as shown in Figure 34b.…”

Application of High-Density Electropulsing to Improve the Performance of Metallic Materials: Mechanisms, Microstructure and Properties

“…There are areas of ultra-fine grain structure and nanostructure coexisting in the majority EPTed metals due to the rapid heating and cooling process. The future outlook demands such features as oriented texture to be dominant and manufactured in a controlled fashion rather than a curious and scientifically interesting anomaly [ 141 ]. The most appropriate pre-treatment before EPT is cold work, such as rolling and extrusion, since the effect of electric current pulses on recrystallization can be amplified in the pre-deformed materials [ 142 , 143 ].…”

Depth-Sensing Indentation Creep Behavior of Nanostructured Thermal Barrier Coatings from As-Synthesized t’-8YSZ Feedstocks

“…APS is the most usual and extensive method to prepare TBCs [10,11]. Research and development of nanotechnology and nanomaterials have further promoted and expanded the development of APS [12]. The plasma-sprayed nanostructured 8YSZ coatings can be obtained using nanostructured powder feedstocks and it has been demonstrated that nanostructured 8YSZ coatings present more remarkable properties than microstructured counterparts [13][14][15][16][17][18][19][20].…”