The use of cathodic cage material and plasma current density for the enhancement of the surface properties of plasma nitrided steel

Significance Statement

Plasma Nitriding is a conventional industrial thermochemical process used for improving the surface mechanical and tribological properties of different alloys including steels. Cathodic cage plasma nitriding (CCPN) is a relatively recent alteration of the conventional plasma nitriding (CPN) design, which eliminates several shortcomings of CPN. In a short duration environment-friendly CCPN process, the surface hardness can be enhanced several times. Therefore, with just a 10 % increase in the cost of the samples, their lifetime can be increased several times. Plain carbon steel is much cheaper than the alloy steel, but generally, it has limited use in several industrial applications due to its unsuitability for plasma nitriding. The work shows the first industrially compatible process to nitride the plain carbon steel.

In CCPN process, a perforated cylinder (or cathodic cage) surrounds the specimens to be nitrided. The discharge is established between the grounded vacuum vessel (anode) and the perforated cylinder (cathode). A pulsed dc power supply is used to avoid switching of the discharge from abnormal glow to the arc mode. The cathode cage material sputtered by the accelerated nitrogen ions is eventually deposited on the specimens. The work showed that the effectiveness of the nitriding performance is linked to the peak discharge current density (current/cathode cage area). The peak discharge current density is increased independent of plasma power, by decreasing the duty cycle to 15 % and reducing the cathodic cage diameter. When an AISI-304 (containing 18.8% Chromium(Cr)) cathodic cage is used for the nitriding of plain carbon steel at high current density, some Cr is deposited on the sample surface which helps to trap nitrogen. This deposition of nitrogen-trapping chromium from the AISI-304 cathodic cage enabled successful nitriding of plain carbon steel, which is generally considered inappropriate for plasma nitriding.

The concept is extended by using two steps of nitriding using aluminum and AISI -304 cathodic cages in alternate order, for the nitriding of alloy steel. The double step process developed a duplex coating in a single CCPN setup, with much better properties than the single step. Besides surface hardness up to seven times, corrosion and wear rates are significantly reduced. The results are verified by the XRD and the surface and cross-sectional SEM images. The use of higher current densities and various cage materials in CCPN system can be used to develop multi-layer coatings using a single industrially scalable setup.


  1. Naeem, M. Shafiq, M. Zaka-ul-Islam, A. Ashiq, J. C. Díaz-Guillén, M. Shahzad, M. Zakaullah, Enhanced surface properties of plain carbon steel using plasma nitriding with austenitic steel cathodic cage, Mater. Des. 108 (2016) 745–753.
  2. Naeem, M. Waqas, I. Jan, M. Zaka-ul-Islam, J. C. Díaz-Guillén, N. U. Rehman, M. Shafiq, M. Zakaullah, Influence of pulsed power supply parameters on active screen plasma nitriding, Surf. Coat. Technol. 300 (2016) 67–77.
  3. Naeem, M. Shafiq, M. Zaka-ul-Islam, N. Nawaz, J. C. Díaz-Guillén, M. Zakaullah, Effect of cathodic cage size on plasma nitriding of AISI 304 steel, Mater. Lett. 181 (2016) 78–81.
  4. Naeem, M. Zaka-ul-Islam, M. Shafiq, M.I. Bashir, J.C. Díaz-Guillén, M. Zakaullah, Influence of cathodic cage diameter on mechanical properties of plasma nitrided AISI 304 steel, Surf. Coat. Technol. 309 (2017) 738-748.
  5. Naeem, M. Shafiq, M. Zaka-ul-Islam, J. C. Díaz-Guillén, C. M. Lopez-Badillo, N. Ullah, M. Zakaullah, Improved surface properties of AISI-304 by novel duplex cathodic cage plasma nitriding, Mater. Lett. 189 (2017) 213–216.

The use of cathodic cage material and plasma current density for the enhancement of the surface properties of plasma nitrided steel 1- Advances in Engineering
Figure Legend 1: Pictorial view of CCPN system.
The use of cathodic cage material and plasma current density for the enhancement of the surface properties of plasma nitrided steel 2- Adv
Figure Legend 2: Cross-sectional SEM image of the duplex nitrided sample (first treated by the AISI-304 steel cathodic cage and then by the aluminum cathodic cage.
The use of cathodic cage material and plasma current density for the enhancement of the surface properties of plasma nitrided steel 3- Adv
Figure Legend 3: Elemental line scan profile of the duplex nitrided sample.

About the author

Dr. J. C. Díaz-Guillén is a PhD graduated from Centro de Investigación en Materiales Avanzados CIMAV in Chihuahua México and currently he is working as CONACYT-Cathedratic research at Corporación Mexicana de Investigación en Materiales in Saltillo, Coahuila México.

His research topics are focused on plasma assisted technologies for enhance surface properties, as wear and corrosion, of metallic materials. He has published over 15 papers in peer-reviewed journals and he has participated in several congress related to surface engineering.

About the author

Mr. Muhammad Naeem has recently submitted his doctoral dissertation in experimental plasma physics at the Quaid-i-Azam University, Islamabad, Pakistan. Before pursuing his PhD program, he also completed his M. Phil degree from the same reputed institution of higher learning.

His field of specialization is plasma material processing and plasma diagnostics. He has published 9 papers in various high-impact journals in the years 2016 and 2017.

About the author

Dr. Mujahid Zaka-ul-Islam is an Assistant Professor of Physics at Jazan University Saudi Arabia, since 2013. He obtained his MSc with distinction and Ph.D. in Plasma Physics from Queens University Belfast UK in 2009 and 2012, respectively. Previously, he had worked as a postdoctoral researcher at University of Antwerp Belgium (2012-2013).

He is interested in low temperature plasma diagnostics and its environmental and surface engineering applications. He has published over 20 papers in peer-reviewed journals.

About the author

Dr. Muhammad Zakaullah obtained Ph.D. from Quaid-i-Azam University Islamabad Pakistan and postdoctoral experience at Imperial College London. He has served as Chairman Department of Physics and Dean Faculty of Natural Sciences at Quaid-i-Azam University, Islamabad, Pakistan.

He is founding member of Asian African Association for Plasma Training. His research started from neutrons and X-rays emission from Plasma Focus devices. A decade later it diverted to ion beams from Plasma Focus and their interaction with different targets. Now a days, it is more focused on low temperature plasma diagnostics and its applications for surface engineering.

He has published over 160 papers in peer-reviewed journals and supervised eighty plus M.Phil. and Ph.D. theses. He is also serving as Associate Editor of Springer Journal of Fusion Energy.

About the author

Dr. M. Shafiq, is presently Associate Professor of Physics at the Quaid-i-Azam University (QAU) Islamabad. He obtained the Ph.D. degree in Physics from Quaid-i-Azam University, Islamabad. At QAU, he is engaged in the experimental Plasma Physics laboratory and worked on low energy Plasma Focus devices and the diagnostics like time-resolved and time-integrated neutron, X-ray and charged particle beam detectors.

He has conducted an in-depth investigation on the X-ray emission from the plasma focus device and correlated the emission parameters with the operating conditions to enhance X-ray yield. He used a simple and cost effective technique for measurement of X-ray fluence anisotropy. It would be equally useful for other pulsed sources. He has more than 20 years of college/ university teaching and research experience and has published more than fifty research papers in referred journals of international repute.

His current scientific interest is Physical vapor deposition (PVD), capacitively coupled plasma (CCP), inductively coupled plasma (ICP) and their industrial applications.


M. Naeem1, M. Zaka-ul-Islam2, J.C. Díaz-Guillén3, M. Shafiq1, M. Zakaullah1*. The use of cathodic cage material and plasma current density for the enhancement of the surface properties of plasma nitrided steel. Advances in Engineering feature, 5th April 2017.

Show Affiliations
  1. Department of Physics, Quaid-i-Azam University, 45320 Islamabad, Pakistan.
  2. Department of Physics, Faculty of Science, Jazan University, P.O. Box 114, Jazan, Saudi Arabia.
  3. Department of Physics, Faculty of Science, Jazan University, P.O. Box 114, Jazan, Saudi Arabia.

* Corresponding author: [email protected]  (M. Zakaullah).

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