Plasma nitriding of aluminium in a pulsed dc glow discharge of nitrogen

¹ Department of Physics, University of Peshawar, Peshawar, 25120, Pakistan
² Department of Physics, Gomal University, D.I. Khan, 29050, Pakistan
³ Department of Physics, COMSATS Institute of Information Technology (CIIT), Park Road, Islamabad, 4400, Pakistan
⁴ National Tokamak Fusion Program, Islamabad, 3329, Pakistan
⁵ Department of Physics, Quaid-i-Azam University, Islamabad, 45320, Pakistan

Corresponding author: mzakaullah@qau.edu.pk

Received: 16 June 2009
Revised: 8 September 2009
Accepted: 9 November 2009
Published online: 26 January 2010

Abstract

Plasma nitriding of aluminium in a 50 Hz pulsed-dc glow discharge is studied for different ion-current densities (2.0-5.0 mA cm^-2) by keeping the corresponding discharge parameters such as treatment time, chamber pressure, substrate temperature and gas composition same. The treated samples are analysed for changes induced in surface properties using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Vickers's micro-hardness testing. XRD showed the downshift in the original diffraction peak corresponding to (111) plane reflection along with the emergence of new diffraction peak corresponding to (220) plane reflection, confirming the N-diffusion into existing Al-lattice and formation of AlN compound. Surface hardness is significantly improved which might be attributed to the diffusion of nitrogen and compound layer formation.