Theoretical and Experimental Studies of Ethanol Decomposition and Electrooxidation over Pt-Modified Tungsten Carbide

2014 ◽  
Vol 161 (8) ◽  
pp. E3165-E3170 ◽  
Author(s):  
Thomas G. Kelly ◽  
Alan L. Stottlemyer ◽  
Xiaofang Yang ◽  
Jingguang G. Chen
Keyword(s):  
Tungsten Carbide ◽  
Experimental Studies ◽  
Ethanol Decomposition

Replacing Platinum with Tungsten Carbide (WC) for Reforming Reactions: Similarities in Ethanol Decomposition on Ni/Pt and Ni/WC Surfaces

ACS Catalysis ◽  
2011 ◽  
Vol 1 (4) ◽  
pp. 390-398 ◽  
Author(s):  
Hui Ren ◽  
Danielle A. Hansgen ◽  
Alan L. Stottlemyer ◽  
Thomas G. Kelly ◽  
Jingguang G. Chen
Keyword(s):  
Tungsten Carbide ◽  
Ethanol Decomposition ◽  
Reforming Reactions

scholarly journals Effects of Mechanical Alloying on Sintering Behavior of Tungsten Carbide-Cobalt Hard Metal System

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Ahmet Ozan Gezerman ◽  
Burcu Didem Çorbacıoğlu
Keyword(s):  
Mechanical Alloying ◽  
Tungsten Carbide ◽  
Particle Surface ◽  
Experimental Studies ◽  
Hard Metal ◽  
Sintering Behavior ◽  
Alloyed Powder ◽  
Tungsten Carbides ◽  
Mechanically Alloyed ◽  
Particle Surface Area

During the last few years, efforts have been made to improve the properties of tungsten carbides (WCs) by preparing composite materials. In this study, we prepared WC particles by mechanical alloying and investigated the effects of mechanical alloying conditions, such as mechanical alloying time and mechanically alloyed powder ratio, on the properties of 94WC-6Co. According to experimental studies, increasing the mechanical alloying time causes an increase in the density of tungsten carbide samples and a decrease of crystal sizes and inner strength of the prepared materials. With the increase of mechanical alloying time, fine particle concentrations of tungsten carbide samples have increased. It is observed that increasing the mechanical alloying time caused a decrease of the particle surface area of tungsten carbide samples. Besides, the amount of specific phases such as Co3W3C and Co6W6C increases with increasing mechanical alloying time. As another subject of this study, increasing the concentration of mechanically alloyed tungsten carbides caused an increase in the densities of final tungsten carbide materials. With the concentrations of mechanically alloyed materials, the occurrence of Co6W6C and Co3W3C phases and the increase of crystallization are observed.

Experimental Studies on Optimization of WEDMed Tungsten-Carbide Metal Matrix Composite

2014 ◽  
Vol 984-985 ◽  
pp. 377-383
Author(s):  
Veluswamy Muthuraman ◽  
Raju Ramakrishnan ◽  
G. Siddarth ◽  
V. Nikilesh ◽  
V. Rangaraja
Keyword(s):  
Surface Roughness ◽  
Tungsten Carbide ◽  
Material Removal Rate ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Experimental Studies ◽  
Critical Parameters ◽  
Work Piece ◽  
Off Time

Wire Electrical discharge Machining plays an important role in the field of electrically conductive material machining. The process has grown exponentially in the past decade due to advantages like high accuracy, precision, ability to achieve complex, intricate shapes on components, unruffled by material hardness, less noise, leaves little residual stress on work piece and the advantage of unmanned machining. A stochastic process in nature, it is difficult to determine parameters that improve cutting rate and surface roughness, the main stay of the metal machining industries. Tungsten carbide is widely used in tool and die making industry mainly due to its extreme hardness; wear resistance, toughness and high temperature stability. Finding optimized parameters for machining performance improvement and optimization would help the manufacturing community. Design of experiments with an orthogonal array of L 27, on four critical parameters On-Time, Off-Time, Wire Speed and Peak current with three levels had been carried out. The experimental results were optimized using Taguchi analysis. Analysis of variance was done. Confirmation tests validated that the results for material removal rate and surface roughness, 5.021mm3/min and3.26μm with improvement. The most influential parameters were off-time, wire-speed and on-time for material removal rate and wire-speed current and on-time for surface roughness. The optimum levels were reported.

Hardening tungsten carbide by alloying elements with high work function

2019 ◽  
Vol 75 (6) ◽  
pp. 994-1002
Author(s):  
Hao Lu ◽  
Chong Zhao ◽  
Haibin Wang ◽  
Xuemei Liu ◽  
Rong Yu ◽  
...  
Keyword(s):  
Tungsten Carbide ◽  
Work Function ◽  
Experimental Studies ◽  
High Hardness ◽  
Alloying Elements ◽  
Metal Carbides ◽  
Superhard Materials ◽  
New Type ◽  
Work Functions ◽  
High Work

There is intensive searching for superhard materials in both theoretical and experimental studies. Refractory and transition metal carbides are typical materials with high hardness. In this study, first-principles calculations were performed first to analyze the electronic structures and mechanical properties of the tungsten-carbide-based compounds. The results indicated that tungsten carbide could be hardened by alloying elements with high work functions to tailor the Fermi level and electron density. Guided by the calculations, a new type of tungsten carbide alloyed with Re was synthesized. The Young's modulus and hardness of the Re-alloyed tungsten carbide are increased by 31% and 44%, respectively, as compared with those of tungsten carbide. This study provides a new methodology to design superhard materials on a feasible electronic base using work function as a simple guiding parameter.

Experimental Studies in Electro-Machining

1973 ◽  
Vol 95 (4) ◽  
pp. 945-950 ◽  
Author(s):  
N. H. Cook ◽  
G. B. Foote ◽  
P. Jordan ◽  
B. N. Kalyani
Keyword(s):  
Tungsten Carbide ◽  
Experimental Studies ◽  
Electrochemical Machining ◽  
Operating Voltage ◽  
Charged Interaction ◽  
Positively Charged

Three separate studies are discussed: (a) The effect of operating voltage, on electrochemical machining of tungsten carbide, was found to be very important, determining whether machining occurred or not. Best results were obtained in the 50–60 region. (6) “Discharge machining of glass” was studied in a system in which discharges between a tool and an electrolyte cause erosion of the glass. While the mechanism of erosion has not been identified, drilling rates up to 0.1 in/min. have been obtained. (c) Bubbles, formed by electrochemical machining (H2), behave as though positively charged. Interaction between the “charged” bubbles and an a-c field produce a desirable dispersion of the bubbles.

3-D reconstruction and analysis of mammalian mitotic spindle structure

1992 ◽  
Vol 50 (1) ◽  
pp. 578-579
Author(s):  
Kent McDonald ◽  
David Mastronarde ◽  
Rubai Ding ◽  
Eileen O'Toole ◽  
J. Richard McIntosh
Keyword(s):  
Cross Sections ◽  
Mitotic Spindle ◽  
Experimental Studies ◽  
Video Camera ◽  
Three Dimensions ◽  
Mitotic Spindles ◽  
Black And White ◽  
Reconstruction Methods ◽  
Spindle Structure ◽  
Tissue Culture Line

Mammalian spindles are generally large and may contain over a thousand microtubules (MTs). For this reason they are difficult to reconstruct in three dimensions and many researchers have chosen to study the smaller and simpler spindles of lower eukaryotes. Nevertheless, the mammalian spindle is used for many experimental studies and it would be useful to know its detailed structure.We have been using serial cross sections and computer reconstruction methods to analyze MT distributions in mitotic spindles of PtK cells, a mammalian tissue culture line. Images from EM negatives are digtized on a light box by a Dage MTI video camera containing a black and white Saticon tube. The signal is digitized by a Parallax 1280 graphics device in a MicroVax III computer. Microtubules are digitized at a magnification such that each is 10-12 pixels in diameter.

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