Effects of Heat Treatment on the Tribological Behavior of Ni-SiOC Nanocomposite Coatings
| dc.contributor.author | Klu, Edwin Eyram | en |
| dc.contributor.committeechair | Cai, Wenjun | en |
| dc.contributor.committeemember | Murayama, Mitsuhiro | en |
| dc.contributor.committeemember | Reynolds, William T. Jr. | en |
| dc.contributor.department | Materials Science and Engineering | en |
| dc.date.accessioned | 2025-06-06T17:32:22Z | en |
| dc.date.available | 2025-06-06T17:32:22Z | en |
| dc.date.issued | 2025-05-08 | en |
| dc.description.abstract | Amorphous-ceramic-reinforced-metals (ACRMs) have excellent mechanical properties across a wide temperature range, which holds great promise as wear-resistant coatings under complex service conditions. Recent studies show that proper annealing results in enhanced tensile strength and ductility of ACRMs due to microstructure evolution that promotes co-deformation between the amorphous and crystalline nanograins. The goal of this research is to understand how annealing affects the wear behavior of ACRMs, by linking the wear-induced deformation mechanisms to subsurface microstructural evolution. Specifically, co-sputtering of Ni, SiC and SiO2 targets with further post annealing at 600 ℃ and 800 ℃ was employed in the synthesis of Ni-SiOC ACRMs, comprising of submicron Ni matrix containing amorphous SiOC ceramic particles. Transmission electron microscopy (TEM) characterization revealed that annealing led to the growth of both the Ni and SiOC phases. Room temperature reciprocal wear test of both the as-deposited and annealed ACRM samples was performed under 1 N constant load using a 4 mm diameter alumina ball as counterbody, at 1 Hz frequency, 5 mm stroke distance for 10 mins. Wear rate decreased with increase in annealing temperature up to 600 ℃ before increasing with increase in annealing temperature. Post wear characterization revealed the refinement of the Ni and SiOC reinforcing phases, which serves as the basis for the discussion on the effects of annealing temperature on the wear-induced deformation mechanisms occurring in the nanocomposite. | en |
| dc.description.abstractgeneral | Amorphous-ceramic-reinforced metals (ACRMs) are special classes of materials that are made up of a combination of metals and ceramic particles (usually in smaller sizes) to form a composite material. These materials have high strength and toughness, even when used in applications that require high temperatures, making them an excellent choice for protective coatings for use in harsh and extreme conditions. Recent studies and research show that heat treatment of such materials at an optimal temperature can improve their strength, toughness and overall mechanical properties. This is as a result of changes in the microstructure of the composite material which aids in improving its mechanical properties and efficient use in various applications including high temperature applications. The goal of this research was to explore the effect heat treatment has on the microstructural alteration of the nanocomposite material and eventually the effect on its mechanical properties (particularly its wear behaviour). This was achieved by co-sputtering nickel (Ni), silicon carbide (SiC), and silicon dioxide (SiO₂) to form a Ni-SiOC nanocomposite coating material. Subsequent heat treatment at 600 °C and 800 °C was performed, which led to an increase in the grain sizes with increase in annealing temperature. Reciprocating wear tests using an alumina ball was performed with a load of 1 N, 1 Hz frequency, over a 5 mm distance for 10 minutes. The results showed that the nanocomposite became more resistant to wear when heated to 600 °C, but less wear resistant after being heat treated to 800 °C. After the wear tests, various microstructural characterization tests were performed to clearly analyze the microstructural changes occurring and link it to the observed wear test results obtained. Heat treatment, grain refinement, interplay between hardness and modulus of elasticity were a major contributory factor to the observed wear behaviour of the nanocomposite coating. | en |
| dc.description.degree | Master of Science | en |
| dc.format.medium | ETD | en |
| dc.format.mimetype | application/pdf | en |
| dc.identifier.uri | https://hdl.handle.net/10919/135101 | en |
| dc.publisher | Virginia Tech | en |
| dc.rights | In Copyright | en |
| dc.rights.uri | http://rightsstatements.org/vocab/InC/1.0/ | en |
| dc.subject | Tribology | en |
| dc.subject | Wear | en |
| dc.subject | Nanocomposite | en |
| dc.subject | Microstructure | en |
| dc.title | Effects of Heat Treatment on the Tribological Behavior of Ni-SiOC Nanocomposite Coatings | en |
| dc.type | Thesis | en |
| dc.type.dcmitype | Text | en |
| thesis.degree.discipline | Materials Science and Engineering | en |
| thesis.degree.grantor | Virginia Polytechnic Institute and State University | en |
| thesis.degree.level | masters | en |
| thesis.degree.name | Master of Science | en |