skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • NSF Public Access
  • Search Results
  • Effect of dispersed oxide of cerium, lanthanum and thorium on the corrosion behaviour of tungsten in 3.5 wt-% NaCl solution
Title: Effect of dispersed oxide of cerium, lanthanum and thorium on the corrosion behaviour of tungsten in 3.5 wt-% NaCl solution
Tungsten has unique physical and chemical properties that make it ideal for high-temperature applications. At room temperature, it is being considered for medical applications due to its protection by an oxide/hydroxide film. However, breakdown of the oxide film and tungsten dissolution can have adverse effects on human health. This study investigates the corrosion of tungsten with and without dispersed oxides of rare-earth elements (ThO2, CeO2, and La2O3) in a 3 wt-% NaCl solution using electrochemical techniques. The results suggest that tungsten dissolution occurs after the formation of an oxide film, likely WO3, on the surface of tungsten and dispersed oxide tungsten. La2O3 and CeO2 may decrease the corrosion rate of tungsten, while WThO2/tungsten has similar corrosion rates to tungsten. The study concludes that CeO2 or La2O3 could replace ThO2 in tungsten due to the radioactive nature of Th.  more » « less
Award ID(s):
2108462
PAR ID:
10494559
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
Taylor and Francis
Date Published:
Journal Name:
Corrosion Engineering, Science and Technology
Volume:
58
Issue:
4
ISSN:
1478-422X
Page Range / eLocation ID:
423 to 430
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; (, Physical Chemistry Chemical Physics)
    Understanding the corrosion behavior of glasses in near-neutral environments is crucial for many technologies including glasses for regenerative medicine and nuclear waste immobilization. To maintain consistent pH values throughout experiments in the pH = 7 to 9 regime, buffer solutions containing tris(hydroxymethyl)aminomethane (“Tris”, or sometimes called THAM) are recommended in ISO standards 10993-14 and 23317 for evaluating biomaterial degradation and utilized throughout glass dissolution behavior literature—a key advantage being the absence of dissolved alkali/alkaline earth cations ( i.e. Na + or Ca 2+ ) that can convolute experimental results due to solution feedback effects. Although Tris is effective at maintaining the solution pH, it has presented concerns due to the adverse artificial effects it produces while studying glass corrosion, especially in borosilicate glasses. Therefore, many open questions still remain on the topic of borosilicate glass interaction with Tris-based solutions. We have approached this topic by studying the dissolution behavior of a sodium borosilicate glass in a wide range of Tris-based solutions at 65 °C with varied acid identity (Tris–HCl vs. Tris–HNO 3 ), buffer concentration (0.01 M to 0.5 M), and pH (7–9). The results have been discussed in reference to previous studies on this topic and the following conclusions have been made: (i) acid identity in Tris-based solutions does not exhibit a significant impact on the dissolution behavior of borosilicate glasses, (ii) ∼0.1 M Tris-based solutions are ideal for maintaining solution pH in the absence of obvious undesirable solution chemistry effects, and (iii) Tris–boron complexes can form in solution as a result of glass dissolution processes. The complex formation, however, exhibits a distinct temperature-dependence, and requires further study to uncover the precise mechanisms by which Tris-based solutions impact borosilicate glass dissolution behavior. 
    more » « less
  2. ; ; ; ; (, Frontiers in Materials)
    Multifunctional coatings with simultaneous antibacterial and anticorrosive properties are essential for marine environments, oil and gas industry, medical settings, and domestic/public appliances to preserve integrity and functionality of pipes, instruments, and surfaces. In this work, we developed a simple and effective method to prepare graphene oxide (GO)-hybridized waterborne epoxy (GOWE) coating to simultaneously improve anticorrosive and antibacterial properties . The effects of different GO filler ratios (0.05, 0.1, and 0.5, 1 wt%) on the electrochemical and antibacterial behaviors of the waterborne epoxy coating were investigated over short- and long-term periods. The electrochemical behavior was analyzed with salt solution for 64 days. The antibacterial effect of GOWE coating was evaluated with Shewanella oneidensis (MR-1), which is a microorganism that can be involved in corrosion. Our results revealed that concentrations as low as 0.1 wt% of the GO was effective performance than the waterborne epoxy coating without graphene oxide. This result is due to the high hydrophilicity of the graphene oxide fillers, which allowed great dispersion in the waterborne epoxy coating matrix. Furthermore, this study used a corrosion relevant bacterium as a model organism, that is, Shewanella oneidensis (MR-1), which is more relevant for real-word applications. This as-prepared GO-hybridized waterborne polymeric hybrid film provides new insight into the application of 2D nanomaterial polymer composites for simultaneous anticorrosive and antibacterial applications. 
    more » « less
  3. ; ; ; (, American Society for Composites-Thirty-Seventh Technical Conference)
    Graphene oxide (GO) films have a great potential for aerospace, electronics, and renewable energy applications due to their low cost and unique properties. For structural applications, they can achieve an exceptional combination of damping and stiffness. This study investigates the effect of packing density, reduction, and water removal on stiffness and damping of graphene oxide films. GO sheets dispersed in water are passed through a filter and deposited on a removable substrate. Through variations of the film fabrication process, films of both GO and reduced GO (rGO) are produced with varying levels of packing. Heat treatment is also used to remove the water in half of the films. The degree of packing is assessed through film density calculations. Microscopy as well as Raman and X-ray spectroscopy are used to measure the degree of packing while Dynamic Mechanical Analysis (DMA) is used to quantity mechanical damping and storage modulus of specimens in tension. Correlating mechanical properties to structure of films revealed new understanding of damping and stress transfer mechanisms in these materials. Optimal structures resulted in superior combinations of stiffness (18 GPa) and damping (0.14), potentially paving the way for using GO based films in advanced structural applications. 
    more » « less
  4. ; ; ; (, Journal of Applied Physics)
    Thermochromic vanadium dioxide thin films have attracted much attention recently for constructing variable-emittance coatings upon their insulator-metal phase transition for dynamic thermal control. However, fabrication of high-quality vanadium dioxide thin films in a cost-effective way is still a challenge. In addition, the phase transition temperature of vanadium dioxide is around 68 °C, which is higher than most of terrestrial and extraterrestrial applications. In this study, we report the fabrication and characterization of tungsten-doped vanadium dioxide thin films with lowered phase transition temperatures via co-sputtering, furnace oxidation, and thermal annealing processes for wider application needs. Doping is achieved by co-sputtering of tungsten and vanadium targets while the doping level is varied by carefully controlling the sputtering power for tungsten. Doped thin film samples of 30 nm thick with different tungsten atomic concentrations are prepared by co-sputtering onto undoped silicon wafers. Optimal oxidation time of 4 h is determined to reach full oxidation in an oxygen-rich furnace environment at 300 °C. A systematic thermal annealing study is carried out to find the optimal annealing temperature and time. By using an optical cryostat coupled to an infrared spectrometer, the temperature-dependent infrared transmittance of fully annealed tungsten-doped vanadium dioxide thin films is measured in a wide temperature range from −60 to 100 °C. The phase transition temperature is found to decrease at 24.5 °C per at. % of tungsten doping, and the thermal hysteresis between heating and cooling shrinks at 5.5 °C per at. % from the fabricated vanadium dioxide thin films with tungsten doping up to 4.1 at. %. 
    more » « less
  5. ; ; (, Materials Advances)
    Elastomers are an important class of polymers for many applications. Often, additives are added to the polymer matrix of elastomers to promote vulcanization or enhance physical or chemical properties. In this study, vapor phase infiltration (VPI) is investigated for transforming unvulcanized cis -polyisoprene (from natural rubber) into an organic/inorganic hybrid material. Specifically, we examine single-cycle infiltration with diethylzinc (DEZ) and water to form infiltrated zinc oxide species. Interestingly, low-temperature pre-heating of the cis -polyisoprene acutely affects the processes of infiltration, including diffusivity, maximum solubility, and chemical reactivity. We attribute these effects to a combination of film relaxation and oxidation. Independent of thermal pre-treatments, all infiltration processes exhibited consistent zinc oxide loading irrespective of purge time between the DEZ and water doses, indicating the presence of a strongly bound intermediate state between the DEZ precursor and the cis -polyisoprene polymer. Increasing infiltration process temperature accelerates diffusion and lowers the maximum solubility, in accordance with Fick's law and gas phase sorption equilibrium. Resulting organic–inorganic hybrid films show enhanced resistance to dissolution in toluene, a good solvent for the pure polymer. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email