scholarly journals Gas-Dynamic Specifications of Glow Discharge During Ion Nitriding Process

2018 ◽  
Vol 17 (5) ◽  
pp. 368-377
Author(s):  
M. N. Bosyakov ◽  
A. A. Kozlov
Keyword(s):  
Glow Discharge ◽  
Flow Rate ◽  
Current Density ◽  
Discharge Current ◽  
Surface Hardening ◽  
Nitriding Process ◽  
Vacuum System ◽  
Ion Nitriding ◽  
Discharge Current Density ◽  
Gas Dynamic

Ion-plasma nitriding in glow discharge is a widely used method of surface hardening in the industrialized countries of the world and it is the most modern and technological type of surface hardening of machine parts, molds, dies and cutting tools. However there is no detailed review in the literature of technical characteristics and operation of a gas-vacuum part in ion nitriding units and it does not allow estimating electric power consumption for operation of a gas-vacuum system while assessing efficiency of the given equipment. The paper considers problems pertaining to relationship of gas-dynamic parameters of the nitriding process (pressure and gas flow rate) and energy characteristics of the glow discharge (current density, discharge voltage) during ion nitriding at industrial plants and their impact on the process. Calculation-practical modeling of a vacuum system for an ion nitriding installation shows that it is advisable to use vacuum units which represent consistently connected forevacuum and two-rotor pumps in order to ensure independent control of a pumping speed and flow rate of the gas mixture. Such approach makes it possible to carry out nitriding processes in a wide range of pressures with the possibility to provide high plasma gas rates at a low pressure, in particular, when processing large areas. The paper has revealed temperature interrelations, chamber pressure and glow discharge current density that ensure its existence in the abnormal form. It has been shown that at lower operational pressure during the process, higher degree of discharge abnormality can be provided at uniform temperature of the batch. Due to this it is possible to attain higher temperature similarity which ensures uniformity of a nitrided layer on all parts of the batch.

One-Step Construction of Ni/Co-Doped C–N Nanotube Composites as Excellent Cathode Catalysts for Neutral Zinc–Air Battery

NANO ◽  
2019 ◽  
Vol 14 (03) ◽  
pp. 1950028 ◽  
Author(s):  
Liang Yu ◽  
Qingfeng Yi ◽  
Xiaokun Yang ◽  
Xiulin Zhou
Keyword(s):  
Current Density ◽  
Discharge Current ◽  
Open Circuit ◽  
Composite Catalyst ◽  
Carbon Paper ◽  
Neutral Medium ◽  
Discharge Current Density ◽  
Nanotube Composites ◽  
Air Battery ◽  
Co Doped

Development of a neutral Zn–air battery is of much significance due to the high stability of zinc in a neutral electrolyte. Here, Ni/Co-doped C–N nanotube composites (C–N, Ni/C–N, Co/C–N, and Ni–Co/C–N) as efficient oxygen reduction reaction (ORR) electrocatalysts in a neutral medium have been prepared by direct pyrolysis of Ni/Co salt, dicyandiamide (DCD) and glucose. Among the synthesized catalysts, Ni–Co/C–N presents a high ORR current density of 8.5[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text] in a 0.5[Formula: see text]mol[Formula: see text][Formula: see text][Formula: see text]L[Formula: see text] KNO3 solution. The ORR electron transfer number of the catalyst Ni–Co/C–N is 3.8, indicating that O2 is almost completely reduced to H2O. A neutral zinc–air battery utilizing a 0.5[Formula: see text]mol[Formula: see text][Formula: see text][Formula: see text]L[Formula: see text] KNO3 solution has been assembled by using the prepared composite catalyst coated on carbon paper as an air cathode, and Zn plate as an anode. The battery with the cathode catalyst Ni–Co/C–N delivers the open-circuit voltage of 1.13[Formula: see text]V and the maximum power density of 65[Formula: see text]mW[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text]. The constant discharge current density of 50[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text], 100[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text] and 150[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text] can last 202[Formula: see text]h, 93[Formula: see text]h and 11[Formula: see text]h, respectively. A stable voltage plateau appears at various discharge current densities. The neutral zinc–air battery can be repeatedly discharged after replacing the zinc anode. Results indicate that the synthesized Ni–Co/C–N catalyst is an excellent cathode material applied to a neutral zinc–air battery, showing broad application prospects as a mobile power source.

Enhanced Electrochemical Performance of CoB Amorphous Alloy through the Addition of Lanthanum

2018 ◽  
Vol 914 ◽  
pp. 102-108
Author(s):  
Wei Zhao ◽  
Yi Lin Liao ◽  
Shu Jun Qiu ◽  
Hai Liang Chu ◽  
Yong Jin Zou ◽  
...  
Keyword(s):  
Amorphous Alloy ◽  
Electrochemical Performance ◽  
Electrochemical Properties ◽  
Discharge Capacity ◽  
Current Density ◽  
Discharge Current ◽  
Electrochemical Impedance ◽  
Chemical Reduction ◽  
High Rate ◽  
Discharge Current Density

In order to investigate the effect of lanthanum on the electrochemical properties of CoB amorphous alloy, Co-Lax-B alloys (x = 0, 0.1, 0.5, and 1) were prepared by chemical reduction method. As negative electrodes in alkaline rechargeable batteries, Co-Lax-B alloys exhibit superior electrochemical properties. For Co-La0.1-B alloy, at the discharge current density of 100 mA/g, the initial discharge capacity is 830.6 mAh/g and the discharge capacity has remained around 317.3 mAh/g even after 100 cycles. Moreover, the high-rate discharge ability (HRD) of Co-La0.1-B alloy electrode at the discharge current density of 300 mA/g, 600 mA/g, and 900 mA/g is 98.16%, 95.17%, and 91.86%, respectively. The anodic polarization (AP) and the electrochemical impedance spectra (EIS) measurements indicate that the kinetics of electrochemical performance of the alloys is remarkably improved with the addition of lanthanum.

Facile construction of ultrathin standing α-Ni(OH)2 nanosheets on halloysite nanotubes and their enhanced electrochemical capacitance

2014 ◽  
Vol 2 (29) ◽  
pp. 11299-11304 ◽  
Author(s):  
Jin Liang ◽  
Bitao Dong ◽  
Shujiang Ding ◽  
Cuiping Li ◽  
Ben Q. Li ◽  
...  
Keyword(s):  
Specific Capacitance ◽  
Current Density ◽  
Discharge Current ◽  
Halloysite Nanotubes ◽  
Cycling Stability ◽  
Hybrid Nanostructures ◽  
Electrochemical Capacitance ◽  
Discharge Current Density ◽  
High Charge ◽  
Charge Discharge

α-Ni(OH)2 nanosheets@HA hybrid nanostructures exhibit an excellent specific capacitance and cycling stability at a high charge–discharge current density.

MnO2 nanowires-decorated carbon fiber cloth as electrodes for aqueous asymmetric supercapacitor

2018 ◽  
Vol 11 (02) ◽  
pp. 1850034 ◽  
Author(s):  
Congcong Hong ◽  
Xing Wang ◽  
Houlin Yu ◽  
Huaping Wu ◽  
Jianshan Wang ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Specific Capacitance ◽  
Current Density ◽  
Discharge Current ◽  
High Specific Capacitance ◽  
High Energy ◽  
Discharge Current Density ◽  
Carbon Fiber Cloth ◽  
A Charge ◽  
Charge Discharge

Manganese dioxide nanowires (MnO2 NWs) anchored on carbon fiber cloth (CFC) were fabricated through a simple hydrothermal reaction and used as integrated electrodes for supercapacitor. The morphology-dependent electrochemical performance of MnO2 NWs was confirmed, yielding good capacitance performance with a high specific capacitance of 3.88[Formula: see text][Formula: see text] at a charge–discharge current density of 5[Formula: see text][Formula: see text] and excellent stability of 91.5% capacitance retention after 3000 cycles. Moreover, the composite electrodes were used to fabricate supercapacitors, which showed a high specific capacitance of 194[Formula: see text][Formula: see text] at a charge–discharge current density of 2[Formula: see text][Formula: see text] and high energy density of 0.108[Formula: see text][Formula: see text] at power density of 2[Formula: see text][Formula: see text], foreboding its potential application for high-performance supercapacitor.

scholarly journals Перспективы развития процессов химико-термического упрочнения легированных сталей (обзорная информация)

2021 ◽  
Vol 70 (2) ◽  
pp. 78-85
Author(s):  
А.П. Прохоров ◽  
А.А. Баранова
Keyword(s):  
Phase Composition ◽  
Glow Discharge ◽  
Hardened Layer ◽  
Nitriding Process ◽  
Ion Nitriding ◽  
Steel Type ◽  
Structure Phase ◽  
Modified Layer

The paper summarizes the results of studies of the structure, phase composition and operational properties of gears made of steel type 38Kh2MYuA, which are observed in the modified layer, after the nitriding process. Much attention is paid to the process of ion nitriding in a glow discharge. The study of the hardened layer showed that there are some differences depending on the temperature of the process. Frequently used methods for the protection of non-aerated surfaces are considered.

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