| Authors: |
Cristian Victor Cojocaru* / National Research Council Canada / Industrial Materials Institute, Canada
Youliang Wang / National Research Council of Canada (NRC), Industrial Materials Institute (IMI), Boucherville, Canada
Rogerio Soares Lima/ National Research Council of Canada (NRC), Industrial Materials Institute (IMI), Boucherville, Canada
|
|
| Abstract: |
The fabrication and patterning of complex ceramic materials with integrated functionality represents an interesting challenge for the development and the application of smart coatings. These are expected to achieve high-performance in for instance sensing, actuating, giving feedback or self-recovering in response to environment change. Probing new routes to prepare these materials and understanding the relationship between their fabrication process, structure and their properties is therefore essential. The approach adopted and further built on in this work is stenciling, i.e., the controlled growth and positioning of structures by direct deposition through metal-supported shadow-masks. The use of a stencil with apertures of various shapes and design, allows for a parallel, direct and site-selective deposition of various materials on almost any type of surface. The proof-of-concept is demonstrated in this work through the thermal spray (via both air-plasma and suspension plasma spraying) of mullite and yttria-stabilized zirconia (YSZ) interlocked patterned coatings that can serve as thermal/environmental barrier coatings. The patterned multilayer architectures, envisioned in this case as solutions to ease the coefficient of thermal expansion mismatch induced stresses, were produced with commercially available powders and custom-made powder suspensions sprayed on silicon coated Si-based ceramics. The structure, mechanical behaviour and performance of the patterned as-sprayed and thermally exposed coatings (in water vapour environment) are discussed in conjunction with continuous layered architectures sprayed from similar feedstock materials. While offering a high degree of freedom in choosing the spraying technique (e.g., APS, SPS, HVOF, Arc, etc), is in principle applicable to the deposition of various materials (e.g., metals, semiconductors, complex ceramic oxides) on a wide range of substrates and represents a stimulating challenge in the applied research faced by the materials science community.
|
|
