| 1. |
- Mulone, Antonio, 1989, et al.
(författare)
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Effect of heat treatments on the mechanical and tribological properties of electrodeposited Fe–W/Al2O3 composites
- 2020
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Ingår i: Wear. - : Elsevier BV. - 0043-1648. ; 448-449
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the influence of heat treatment on the mechanical and tribological properties of electrodeposited Fe–W/Al2O3 composite coatings is studied. The properties of the as-deposited and annealed composites are compared with those of electrodeposited hard chromium coatings. The amorphous structure of the Fe–W matrix transforms into a mixed amorphous-crystalline structure upon annealing at 600 °C for 1 h. The observed microstructural transformations result in a substantial increase of both the hardness and the reduced Young's modulus of the Fe–W/Al2O3 composite coatings, reaching values of 16.3 GPa and 191.7 GPa, respectively. The results on the wear resistance studied under dry friction using ball-on-disc sliding tests show that a low wear rate is obtained for both as-deposited and annealed composite coatings, i.e. ~1.5 × 10−6 mm3/Nm. In contrast, the heat treatments are detrimental for both the hardness and wear resistance of hard chromium coatings. As a consequence, the mechanical and wear properties of the electrodeposited Fe–W/Al2O3 composite coatings, especially after annealing, are superior to the properties of hard chromium coatings. Hence, Fe–W/Al2O3 composite coatings can be considered as a valid and sustainable alternative to hard chromium coatings, particularly in applications where these materials may be exposed to high temperatures.
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| 2. |
- Mulone, Antonio, 1989, et al.
(författare)
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Improvement in the Wear Resistance under Dry Friction of Electrodeposited Fe-W Coatings through Heat Treatments
- 2019
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Ingår i: Coatings. - : MDPI AG. - 2079-6412. ; 9:2, s. 66-
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Tidskriftsartikel (refereegranskat)abstract
- The influence of the microstructural transformations upon heat treatments on the wear resistance of Fe-W coatings is studied. The coatings are electrodeposited from a glycolate-citrate plating bath with 24 at.% of W, and the wear resistance is investigated under dry friction conditions using ball-on-disc sliding tests. The samples were annealed in Ar atmosphere at different temperatures up to 800 °C. The microstructural transformations were studied by means of X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Electron Backscattered Diffraction (EBSD) technique. Except for the coating annealed at 800 °C, all the tested coatings suffered severe tribo-oxidation which resulted in the formation of deep cracks, i.e., ~15 μm in depth, within the wear track. The precipitation of the secondary phases, i.e., Fe2W and FeWO4, on the surface of the sample annealed at 800 °C increased the resistance to tribo-oxidation leading to wear tracks with an average depth of ~3 μm. Hence, the Fe-W coating annealed at 800 °C was characterized with a higher wear resistance resulting in a wear rate comparable to electrodeposited hard chromium coatings, i.e., 3 and 4 × 10−6 mm3/N m, respectively.
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| 3. |
- Nicolenco, Aliona, et al.
(författare)
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Nanocrystalline Electrodeposited Fe-W/Al2O3 Composites: Effect of Alumina Sub-microparticles on the Mechanical, Tribological, and Corrosion Properties
- 2019
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Ingår i: Frontiers in Chemistry. - : Frontiers Media SA. - 2296-2646. ; 7:MAR, s. 241-
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Tidskriftsartikel (refereegranskat)abstract
- In this study, nanocrystalline Fe-Walloy and Fe-W/Al2O3 composite coatings with various contents of sub-microsized alumina particles have been obtained by electrodeposition from an environmentally friendly Fe(III)-based electrolyte with the aim to produce a novel corrosion and wear resistant material. The increase in volume fraction of Al2O3 in deposits from 2 to 12% leads to the grain refinement effect, so that the structure of the coatings change from nanocrystalline to amorphous-like with grain sizes below 20 nm. Nevertheless, the addition of particles to the Fe-W matrix does not prevent the development of a columnar structure revealed for all the types of studied coatings. The observed reduction in both hardness and elastic modulus of the Fe-W/Al2O3 composites is attributed to the apparent grain size refinement/amorphization and the nanoporosity surrounding the embedded Al2O3 particles. In the presence of 12 vol% of Al2O3 in deposits, the wear rate decreases by a factor of 10 as compared to Fe- W alloy tested under dry friction conditions due to the lowering of tribo-oxidation. The addition of alumina particles slightly increases the corrosion resistance of the coatings; however, the corrosion in neutral chloride solution occurs through the preferential dissolution of Fe from the matrix. The obtained results provide a possibility to integrate the nanocrystalline Fe-W/Al2O3 composite coatings into various systems working under dry friction conditions, for example, in high-temperature vacuum systems.
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