Studies on the Hydrogen Absorption Properties of LaNi(5-x)Snx and La0.95Ni4.6Sn0.3 Alloys Using Magnetic and Thermoelectric Power Measurement

Yeong Do Park 대한금속학회 2005 METALS AND MATERIALS International Vol.11 No.3

Recycling and Treatment of Ferrous Grinding Swarf from the Automobile Industry

( Hyunju Lee ),( Brajendra Mishra ),( Youngju Jang ),( Soo-kyung Kim ) 한국폐기물자원순환학회(구 한국폐기물학회) 2019 ISSE 초록집 Vol.2019 No.-

This research focused on the recovery of valuable materials from grinding swarf. We received the ferrous grinding swarf from the automobile industry. Grinding swarf consisted of metal grindings, oil residue, and ceramic particles, and it contains approximately 80 % of the metallic iron. Metalworking fluids provide better-grinding properties by lubricating and cooling the interface between tool and material. However, oil residue covers metal grindings and ceramic particles after its work, and it is undesirable since the oil burns explosively during smelting operations for the metal recovery. For this reason, efficient oil removal from ferrous grinding swarf is essential for its reuse as a secondary metal resource. First, we tried oil removal by aqueous washing under different conditions. Micro-90 and Detergent 8 were used as reagents for oil removal. As a result, over 95% of the oil removed from samples. The oxidation of ferrous grinding swarf was conducted as an alternative route to remove oil as an iron oxide for the pigment application. As-received ferrous grinding swarf was heated in a muffle furnace at different temperature conditions. Moisture evaporation and oil burning were finished at a temperature below 300℃. Based on the surface morphology and chemical phase analyses, hematite powder was obtained from the ferrous grinding swarf. An economic analysis was also conducted to confirm which process is economically feasible for the aqueous washing (hydro) process and oxidation of ferrous (pyro) process using Monte Carlos simulation. The Monte Carlo method is a numerical method for statistical simulation which utilizes sequences of random numbers to perform the simulation rather than analytic calculations. The probability distribution profiles of Fixed Capital Investment (FCI) and Total Capital Investment (TCI) by incorporating the uncertainty associated with the market and process operating environment were calculated using the Monte Carlo simulation methods. As a result, the Net Present Value (NPV) in pyro-process was in the positive range which favors a commercially feasible process. However, aqueous washing process required a huge amount of operating cost due to the reagent cost.

Effects of Cooling Rate on Precipitate Evolution and Residual Stresses in Al–Si–Mn–Mg Casting Alloy

Eunkyung Lee,Caitlin Walde,Brajendra Mishra 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.4

The residual stresses with Different heat treatment conditions have been measured and correlated with the microstructuralbehavior of AA365. 30 and 100 K/min cooling of AA365 inhibited the transformation of precipitates under 773 K, respectively. The alloy cooled at 30 and 100 K/min exhibited tensile residual stresses of 6.2 and 5.4 MPa, respectively, while thealloy cooled at 1 and 10 K/min showed compressive stresses of − 12.8 and − 10.3 MPa, respectively. The formation β′, β″,and other intermetallic compounds aff ected the compressive residual stresses, and that the fracture of the brittle intermetallicphases could reduce the extent of residual stresses in the lattice through plastic deformation.

Multifunctional Ti-Si-B-C-N Tribological Nanocomposite Coatings for Aerospace Applications

Park, In Wook,Mishra, Brajendra,Kim, Kwang Ho,Moore, John J. Trans Tech Publications, Ltd. 2007 Materials science forum Vol.539 No.-

<P>Ti-B-C-N and Ti-Si-B-C-N nanocomposite coatings were deposited on AISI 304 stainless steel substrates by DC unbalanced magnetron sputtering from two (80mol% TiB2-20mol% TiC and 40mol% TiB2-60mol% TiC) composite targets in various Si target powers. The relationship among microstructures, mechanical properties, and tribologiacal properties was investigated. The synthesized Ti-B-C-N and Ti-Si-B-C-N coatings were characterized using x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS). These analyses revealed that the Ti-Si-B-C-N coatings are nanocomposites consisting of solid-solution (Ti,C,N)B2 and Ti(C,N) crystallites distributed in an amorphous TiSi2, SiC, and SiB4 matrix including some carbon, BN, CNx, TiO2, and B2O3 components. The addition of Si to the Ti-B-C-N coating led to percolation of amorphous TiSi2, SiC, and SiB4 phases. The Ti-Si-B-C-N coatings exhibited high hardness and H/E values, indicating high fracture toughness, of approximately 35 GPa and 0.098, respectively. Furthermore, the Ti-Si-B-C-N coatings exhibited very low wear rates ranging from ~3×10-7 to ~16×10-7 mm3/(N·m). The minimum friction coefficient of the Ti-Si-B-C-N coatings was approximately 0.15 at low Si target power between 25W and 50W. A systematic investigation on the microstructures, mechanical properties, and tribological properties of Ti-Si-B-C-N coatings prepared from two TiB2-TiC composite targets and one Si target is reported in this paper.</P>

Evaluation of Iron Nickel Oxide Nanopowder as Corrosion Inhibitor: Effect of Metallic Cations on Carbon Steel in Aqueous NaCl

( A. U. Chaudhry ),( Vikas Mittal ),( Brajendra Mishra ) 한국부식방식학회(구 한국부식학회) 2016 Corrosion Science and Technology Vol.15 No.1

The aim of this study was to evaluate the use of iron-nickel oxide (Fe2O3.NiO) nanopowder (FeNi) as an anti-corrosion pigment for a different application. The corrosion protection ability and the mechanism involved was determined using aqueous solution of FeNi prepared in a corrosive solution containing 3.5 wt.% NaCl. Anti-corrosion abilities of aqueous solution were determined using electrochemical impedance spectroscopy (EIS) on line pipe steel (API 5L X-80). The protection mechanism involved the adsorption of metallic cations on the steel surface forming a protective film. Analysis of EIS spectra revealed that corrosion inhibition occurred at low concentration, whereas higher concentration of aqueous solution produced induction behavior.

Evaluation of Corrosion Resistance Properties of Hexagonal Boron Nitride Based Polymer Composite Coatings for Carbon Steel in a Saline Environment

Fadhel T. Alabdullah,C. Ali,Brajendra Mishra 한국부식방식학회 2022 Corrosion Science and Technology Vol.21 No.1

Herein, we report polyvinyl butyral composites coatings containing various loadings of 72-h bath sonicated hexagonal boron nitride particles (5 μm) to enhance barrier properties of coatings. Barrier properties of coatings were determined in 3.5 wt% NaCl after different time periods of immersion via electrochemical techniques such as open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization test. Coatings containing sonicated hexagonal boron particles exhibited improved corrosion resistance for longer periods of immersion compared to neat coating. We also discussed effects of hexagonal boron nitride on healing properties of polyvinyl butyral. Coatings containing 1.0 wt% loading of sonicated hexagonal boron nitride showed improved long-term barrier properties than coatings with other compositions. The presence of hexagonal boron nitride also affected the healing properties of polyvinyl butyral coatings besides their barrier properties. Such improved barrier properties of composites coatings were attributed to the high aspect ratio, plate-like shape, and electrically insulated nature of the filler.

Development of High Interstitial Stainless Steel and Evaluation of Its NaCl Corrosion Resistance

Cheolmin Ahn,이현주,Yoonseok Lee,Seungchan Cho,Brajendra Mishra,이은경 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.11

High interstitial Fe–Cr–Mn–C–N stainless steels, CN66 (0.38 wt% N + 0.28 wt% C) and CN71 (0.44 wt% N + 0.27 wt% C),were cast under atmospheric pressure to develop a new drill collar for use in petroleum industry. To evaluate the corrosionproperty, CN66 and CN71 were compared with high-Mn stainless steel, P550, which is currently being used as a drill collarmaterial. Through the measurement of the corrosion resistance based on the chemical compositions, CN71 exhibitedthe highest corrosion property, a mean of 35.74, corresponding to strong corrosion resistance. However, CN71 exhibited amean of 0.517 mpy for the corrosion rate compared to 0.37 mpy for P550, after the immersion experiment in 3.5 wt% NaCl. With high C content, the formation of carbide along the grain boundaries in CN71 and CN66 caused intergranular corrosion. However, this could be restricted by heat treatment at 1050 °C and 1180 °C with uniform distributions of chemicalcompositions via air cooling, decreasing the corrosion rates significantly.