Catalytic growth of diamond-like carbon on Fe3C-containing carburized layer through a single-step plasma-assisted carburizing process

Carbon ◽  
2017 ◽  
Vol 122 ◽  
pp. 1-8 ◽  
Author(s):  
Yang Yang ◽  
M.F. Yan ◽  
Y.X. Zhang ◽  
D.Y. Li ◽  
C.S. Zhang ◽  
...  
Keyword(s):  
Single Step ◽  
Diamond Like Carbon ◽  
Catalytic Growth ◽  
Carburized Layer ◽  
Carburizing Process

scholarly journals Acetylene Flow Rate as a Crucial Parameter of Vacuum Carburizing Process of Modern Tool Steels

2016 ◽  
Vol 61 (4) ◽  
pp. 2009-2012 ◽  
Author(s):  
P. Rokicki ◽  
K. Dychton
Keyword(s):  
Chemical Treatment ◽  
Negative Impact ◽  
Aerospace Industry ◽  
Tool Steels ◽  
Vacuum Carburizing ◽  
Layer Characteristic ◽  
Process Methodology ◽  
Carburized Layer ◽  
Treatment Procedures ◽  
Carburizing Process

Abstract Carburizing is one of the most popular and wide used thermo-chemical treatment methods of surface modification of tool steels. It is a process based on carbon diffusive enrichment of the surface material and is applied for elements that are supposed to present higher hardness and wear resistance sustaining core ductility. Typical elements submitted to carburizing process are gears, shafts, pins and bearing elements. In the last years, more and more popular, especially in highly advanced treatment procedures used in the aerospace industry is vacuum carburizing. It is a process based on chemical treatment of the surface in lower pressure, providing much higher uniformity of carburized layer, lower process cost and much lesser negative impact on environment to compare with conventional carburizing methods, as for example gas carburizing in Endo atmosphere. Unfortunately, aerospace industry requires much more detailed description of the phenomena linked to this process method and the literature background shows lack of tests that could confirm fulfilment of all needed requirements and to understand the process itself in much deeper meaning. In the presented paper, authors focused their research on acetylene flow impact on carburized layer characteristic. This is one of the most crucial parameters concerning homogeneity and uniformity of carburized layer properties. That is why, specific process methodology have been planned based on different acetylene flow values, and the surface layer of the steel gears have been investigated in meaning to impact on any possible change in potential properties of the final product.

scholarly journals High-yield single-step catalytic growth of graphene nanostripes by plasma enhanced chemical vapor deposition

Carbon ◽  
2018 ◽  
Vol 129 ◽  
pp. 527-536 ◽  
Author(s):  
Chen-Chih Hsu ◽  
Jacob D. Bagley ◽  
Marcus L. Teague ◽  
Wei-Shiuan Tseng ◽  
Kathleen L. Yang ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Single Step ◽  
High Yield ◽  
Catalytic Growth

scholarly journals Modeling and Simulation of Vacuum Low Pressure Carburizing Process in Gear Steel

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1003
Author(s):  
Jingyu Guo ◽  
Xiaohu Deng ◽  
Huizhen Wang ◽  
Leyu Zhou ◽  
Yueming Xu ◽  
...  
Keyword(s):  
Carbon Concentration ◽  
Surface Hardness ◽  
Low Pressure ◽  
Diffusion Time ◽  
Vacuum Carburizing ◽  
Surface Carbon ◽  
Gear Steel ◽  
Simulated Surface ◽  
Carburized Layer ◽  
Carburizing Process

A combination of simulation and experimental approaches to optimize the vacuum carburizing process is necessary to replace the costly experimental trial-and-error method in time and resources. In order to accurately predict the microstructure evolution and mechanical properties of the vacuum carburizing process, a multi-field multi-scale coupled model considering the interaction of temperature, diffusion, phase transformation, and stress was established. Meanwhile, the improved model is combined with the heat treatment software COSMAP to realize the simulation of the low-pressure vacuum carburizing process. The low-pressure vacuum carburizing process of 20CrMo gear steel was simulated by COSMAP and compared with the experimental results to verify the model. The results indicated that the model could quantitatively obtain the carbon concentration distribution, Fe-C phase fraction, and hardness distribution. It can be found that the carbon content gradually decreased from the surface to the center. The surface carbon concentration is relatively high only after the carburizing stage. With the increase in diffusion time, the surface carbon concentration decreases, and the carburized layer depth increases. The simulated surface carbon concentration results and experimental results are in good agreement. However, there is an error between calculations and observations for the depth of the carburized layer. The error between simulation and experiment of the depth of carburized layer is less than 6%. The simulated surface hardness is 34 HV lower than the experimental surface hardness. The error of surface hardness is less than 5%, which indicates that the simulation results are reliable. Furthermore, vacuum carburizing processes with different diffusion times were simulated to achieve the carburizing target under specific requirements. The results demonstrated that the optimum process parameters are a carburizing time of 42 min and a diffusion time of 105 min. This provides reference and guidance for the development and optimization of the vacuum carburizing process.

Carbon adsorption on doped cementite surfaces for effective catalytic growth of diamond-like carbon: a first-principles study

2017 ◽  
Vol 19 (48) ◽  
pp. 32341-32348 ◽  
Author(s):  
Yang Yang ◽  
Juan Cui ◽  
Lei Li ◽  
Hao Lu ◽  
D. Y. Li ◽  
...  
Keyword(s):  
First Principles ◽  
Diamond Like Carbon ◽  
Catalytic Growth ◽  
Catalytic Activities ◽  
First Principles Study ◽  
Carbon Adsorption

Catalytic activities of alloyed Fe3C for diamond-like carbon growth are predicted.

The New Fluidized Bed Thermo-Chemical Treatment in Chemically Active Powders – CFD Analysis of the Method

2014 ◽  
Vol 902 ◽  
pp. 82-87
Author(s):  
Tomasz Babul ◽  
Aleksander Ciski ◽  
Paweł Oleszczak
Keyword(s):  
Computer Simulation ◽  
Fluidized Bed ◽  
Chemical Treatment ◽  
Layer Structure ◽  
Inert Gas ◽  
Cfd Analysis ◽  
Specific Calculation ◽  
New Type ◽  
Carburized Layer ◽  
Carburizing Process

The paper describes the principles of carrying out of a new type of fluidized bed thermo-chemical treatment in chemically active powders with fluidization by chemically inert gas. The article presents selected results of a computer simulation of chemically active fluidized bed phenomena used in the thermo-chemical treatment of steel. For this purpose, a numerical model of the fluidized bed with a specific calculation area, has been prepared. The results of CFD (Computational Fluid Dynamics) computer simulation of temperature distribution and fluidizing gas mass distribution along the walls of samples placed in the fluidized bed are presented. Results of exemplary carburizing process are given. Metallographic observations and hardness measurements confirm the correctness of the of the carburized layer structure, which was formed on the C22 unalloyed carbon steel.

Electron energy loss spectroscopy of diamond-like carbon thin films

1992 ◽  
Vol 50 (2) ◽  
pp. 1272-1273
Author(s):  
J. Kulik ◽  
Y. Lifshitz ◽  
G.D. Lempert ◽  
S. Rotter ◽  
J.W. Rabalais ◽  
...  
Keyword(s):  
Thin Films ◽  
Energy Loss ◽  
Electron Energy ◽  
Ion Beam ◽  
Diamond Like Carbon ◽  
Ion Beam Deposition ◽  
Chemistry Research ◽  
Carbon Thin Films ◽  
Electron Energy Loss ◽  
Beam Deposition

Carbon thin films with diamond-like properties have generated significant interest in condensed matter science in recent years. Their extreme hardness combined with insulating electronic characteristics and high thermal conductivity make them attractive for a variety of uses including abrasion resistant coatings and applications in electronic devices. Understanding the growth and structure of such films is therefore of technological interest as well as a goal of basic physics and chemistry research. Recent investigations have demonstrated the usefulness of energetic ion beam deposition in the preparation of such films. We have begun an electron microscopy investigation into the microstructure and electron energy loss spectra of diamond like carbon thin films prepared by energetic ion beam deposition.The carbon films were deposited using the MEIRA ion beam facility at the Soreq Nuclear Research Center in Yavne, Israel. Mass selected C+ beams in the range 50 to 300 eV were directed onto Si {100} which had been etched with HF prior to deposition.

Chemical structure of diamond-like carbon thin films

1990 ◽  
Vol 48 (4) ◽  
pp. 710-711
Author(s):  
N.-H. Cho ◽  
K.M. Krishnan ◽  
D.B. Bogy
Keyword(s):  
Electrical Resistivity ◽  
Chemical Structure ◽  
Diamond Like Carbon ◽  
Chemical Structures ◽  
Sputtering Power ◽  
Data Aquisition ◽  
Equilibrium Phases ◽  
Electron Energy Loss ◽  
Power Densities ◽  
Preparation Techniques

Diamond-like carbon (DLC) films have attracted much attention due to their useful properties and applications. These properties are quite variable depending on film preparation techniques and conditions, DLC is a metastable state formed from highly non-equilibrium phases during the condensation of ionized particles. The nature of the films is therefore strongly dependent on their particular chemical structures. In this study, electron energy loss spectroscopy (EELS) was used to investigate how the chemical bonding configurations of DLC films vary as a function of sputtering power densities. The electrical resistivity of the films was determined, and related to their chemical structure.DLC films with a thickness of about 300Å were prepared at 0.1, 1.1, 2.1, and 10.0 watts/cm2, respectively, on NaCl substrates by d.c. magnetron sputtering. EEL spectra were obtained from diamond, graphite, and the films using a JEOL 200 CX electron microscope operating at 200 kV. A Gatan parallel EEL spectrometer and a Kevex data aquisition system were used to analyze the energy distribution of transmitted electrons. The electrical resistivity of the films was measured by the four point probe method.

V884: Demonstration of a Novel Single-Step Percutaneous Access Sheath for Nephrostolithotomy: A Video Presentation

2005 ◽  
Vol 173 (4S) ◽  
pp. 240-240
Author(s):  
Premal J. Desai ◽  
David A. Hadley ◽  
Lincoln J. Maynes ◽  
D. Duane Baldwin
Keyword(s):  
Single Step ◽  
Video Presentation ◽  
Percutaneous Access ◽  
Access Sheath
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