General Information
    • ISSN: 2010-0221
    • Frequency: Bimonthly
    • DOI: 10.18178/IJCEA
    • Editor-in-Chief: Prof. Dr. Shen-Ming Chen
    • Executive Editor: Mr. Ron C. Wu
    • Abstracting/ Indexing: Chemical Abstracts Services (CAS), Ulrich's Periodicals Directory, CABI, DOAJ, Electronic Journals Library, Google Scholar, ProQuest, and Crossref
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Prof. Dr. Shen-Ming Chen
National Taipei University of Technology, Taiwan

IJCEA 2015 Vol.6(5): 341-345 ISSN: 2010-0221
DOI: 10.7763/IJCEA.2015.V6.506

Influence of CO2 Gas in the Electro-Carburisation Process of Mild Steel

Nancy Julius Siambun, Daniel A. Jewell, and George Z. Chen
Abstract—In the attempt to develop a clean process, study has been conducted to determine the effect of absorbed CO2 gas as source of carbon to the case hardening of treated mild steels in the recently developed process of electro-carburisation in non-toxic molten carbonate salts. The concentration of CO2 in the process was varied by purging a CO2 and N2 mixture at flow rate ratios of CO2:N2 of 200:0, 150:50, 100:100, 50:150 and 0:200 mL.min-1. Electro-carburisation was performed in two types of molten salt electrolyte i.e. a mixed anion Na2CO3-NaCl (mole ratio 4:1) and a pure carbonate Li2CO3-K2CO3 (1:1 mole ratio). A voltage of 2.5V was applied between mild steel cathode and an inert SnO2 anode at a carburisation temperature of 800oC for 60 minutes. The results show that greater CO2 concentration produced samples with greater surface hardness and thicker case-hardening, attributed to the increased availability of the electro-active carbon source which was generated by absorption of CO2. Electro-carburisation in Li2CO3-K2CO3 and Na2CO3-NaCl gave surface hardness of 1075 ± 25 HV, however Li2CO3-K2CO3 (540 thickness) gave thicker case depth compared to Na2CO3-NaCl (500 thickness). This is thought to be due to the amount of carbon deposited in each salt; 12.70 wt.% C in Li2CO3-K2CO3 and 11.10 wt.% C in Na2CO3-NaCl.

Index Terms—Molten salt, carburisation, carbonate salt, surface hardness, case depth.

Nancy Julius Siambun is with the Universiti Malaysia Sabah, Engineering Faculty, 88999 Kota Kinabalu, Sabah, Malaysia (e-mail:
Daniel A. Jewell and George Z. Chen are with the University of Nottingham, Department of Chemical and Environmental Engineering, and Energy and Sustainability Research Division, Faculty of Engineering, Nottingham, NG7 2RD, UK (e-mail:,


Cite: Nancy Julius Siambun, Daniel A. Jewell, and George Z. Chen, "Influence of CO2 Gas in the Electro-Carburisation Process of Mild Steel," International Journal of Chemical Engineering and Applications vol. 6, no. 5, pp. 341-345, 2015.

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