|
| Abstract No.: |
|
Scheduled at:
|
Thursday, June 08, 2017, Hall 28 12:20 PM
Tribological Coatings
|
|
| Title: |
Hybrid powder-suspension Al2O3-ZrO2 coatings by axial plasma spraying: Processing, characteristics & tribological behavior
|
|
| Authors: |
Shrikant Joshi* / University West, Sweden
Sneha Goel / University West, SWEDEN
Stefan Björklund/ University West, SWEDEN
Urban Wiklund/ University West, SWEDEN
|
|
| Abstract: |
The ability of suspension plasma spraying (SPS) to overcome difficulties associated with feeding of fine (submicron or nano-sized) powders and achieve more refined microstructures than possible in traditional atmospheric plasma spraying (APS) is now well established. In recent times, the relatively wider use of plasma spray systems that enable axial injection of feedstock has also shown that substantial enhancement in deposition rates/efficiencies can be realized due to the considerably improved thermal exchange between the plasma plume and the injected feedstock. The present paper describes utilization of both the above advances in plasma spraying to create various function-dependent coating architectures through spraying of hybrid powder-suspension feedstock. Modification of the feedstock delivery arrangement to enable separate and individually controllable introduction of powder and suspension axially into the plasma plume will be discussed. This permits sequential as well as simultaneous injection of feedstock, the latter also with continuous variation in relative feed-rates to achieve compositionally gradient coatings. The paper will focus on one specific variant of such hybrid axial plasma spraying that enables deposition of composite coatings by simultaneous injection of a powder and a suspension. Results obtained using the Al2O3-ZrO2 material system as a case study reveal that composite coatings uniquely combining the micron-size features arising from the spray-grade Al2O3 powder and submicron or nano-sized features attributable to the ZrO2 suspension, can be conveniently realized using the above approach. The sprayed coatings were extensively characterized for surface morphology, microstructure, and composition. The tribological behaviour of the coating, determined using scratch and ball-on-disc tests, will be presented. The utility of this method to develop a wide array of composite coatings will also be discussed.
|
|