ELECTROLESS DEPOSITION OF OXIDATION RESISTANT HIGH TEMPERATURE COATINGS IN MOLTEN SALT

Download

10425683.pdf

Date

2021-9-10

Author

Ömür, İshak Emre

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

387
views

44
downloads

Molybdenum and molybdenum alloy (TZM) can be protected against oxygen in hightemperature environment by developing silicide coating on their surface without damaging their mechanical properties. In this study, molybdenum di-silicide was coated on pure molybdenum and its alloy (TZM) surfaces using a molten salt method. NaCl-KCl-NaF eutectic composition was used as salt mixture, and Na2SiF6 and silicon powder were added to the system as silicon source. X-ray diffraction (XRD), Inductively Coupled Plasma – Mass Spectrometer (ICP-MS) and scanning electron microscope (SEM) were used for characterization of the silicide coatings. Effects of operating temperature and time on coating thickness for both pure molybdenum and TZM alloy were studied. Also, effect of silicon sources; Na2SiF6 and silicon powder, on thickness of silicide layer was investigated. While higher operating temperature had limited effect on coating thickness for pure molybdenum samples, thicker coatings were obtained at lower temperatures for TZM alloy samples. Also, longer operating time slightly increased coating thickness for pure molybdenum substrates, however; it had a significant effect for TZM alloy samples for 4 hours of processing time. Although amount of silicon sources in salt mixture had no effect on coating thickness for pure molybdenum samples, amount of silicon in salt mixture had an enormous effect for TZM alloy samples. Also, molybdenum di-silicide coated TZM alloy samples were tested at high-temperature oxygen environment, and it was proved that silicide coating is protective against oxidation by forming silica.

Subject Keywords

Molten salt, high-temperature coatings, molybdenum di-silicide coatings, oxidation, crystallography

URI

https://hdl.handle.net/11511/94244

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Electrochemical Formation of Alloys of Scandium in Molten Salts polat, çağlar; ERDOĞAN, METEHAN; iplikçioğlu, Safder; Karakaya, İshak (2018-02-01) The Al-Sc alloy formation by the reduction of Sc containing compounds in a molten salt containing CaCl2 was investigated in this study. The preliminary tests revealed that Al3Sc intermetallic, which gives the superior properties to this alloy, was successfully formed and distributed homogeneously throughout the Al matrix. XRD, SEM-EDS and optical microscopy analyses were used to confirm the results.
Moisture absorption of composites with interfacial storage Güloğlu, Görkem Eğemen; Hamidi, Youssef K.; Altan, M. Cengiz (2020-07-01) © 2020 Elsevier LtdThermosetting polymer composites are often exposed to wet and humid environments, leading to a considerable reduction in their thermo-mechanical properties. Hence, accurate description of the moisture absorption dynamics, including anomalous effects such as molecular bonding and interfacial storage of moisture, is particularly important. In this study, the hindered diffusion model is extended to include the moisture storage at the interface of impermeable fibers or inclusions within the c...
Carbon coating of magnesium particles Aktekin, Burak; Eyovge, Cavit; Öztürk, Tayfur (2017-10-05) Magnesium when hydrided has low thermal and electrical conductivity and carbon coating would be useful to remedy this for a variety of purposes. In this study, carbon coating was achieved by co-feeding magnesium and methane into a thermal plasma reactor. This yielded carbonaceous material with magnesium particles 5-10 nm in size embedded in graphitic matrix. A further reduction down to 2-3 nm was possible but required reductions in the precursor feed rate. 2 wt% carbon was sufficient to fully protect magnes...
Non-fickian moisture absorption in polymers coated with a thin nanocomposite layer Altan, Altan; Altan, M. Cengiz; Guloglu, GÖRKEM EĞEMEN; Güloğlu, Görkem Eğemen (2014-01-01) Moisture absorption in polymers and polymeric composites is well known to lead to significant degradation in mechanical properties. Most epoxy based composites may absorb 2 to 5 wt.% moisture when they are subjected to humid environments. Moisture absorption in polymers has been often characterized with Fickian or various non-Fickian models to describe the time-dependent absorption phenomena. Previous experiments have shown that dispersing moderate amounts of nanoclay in an epoxy resin can: (i) reduce the t...
Anodization of Ti6Al7Nb Alloy for Orthopaedic Applications İzmir, Merve; Ercan, Batur (null; 2017-12-31) In recent years, nanostructured oxide films on titanium alloy surfaces have gained significant interest due to their electrical, catalytic and biological properties. In literature, there is variety of different approaches to fabricate nanostructured oxide films. Among these methods, anodization technique, which allows fine-tuning of oxide film thickness, feature size, topography and chemistry, is one of the most popular approaches to fabricate nanostructured oxide films on titanium alloys, and it has been w...

Citation Formats

İ. E. Ömür, “ELECTROLESS DEPOSITION OF OXIDATION RESISTANT HIGH TEMPERATURE COATINGS IN MOLTEN SALT,” M.S. - Master of Science, Middle East Technical University, 2021.