The nitridation of zirconium disks is achieved by irradiating energetic nitrogen ions from 2.3 kJ plasma focus device using multiple focus deposition shots (10, 20, 30 and 40) at different angular positions with respect to the anode axis. The X-ray diffraction analysis reveals the evolution of ZrN, Zr2N and Zr3N4 phases of zirconium nitride depending upon the ion energy flux and angular positions. The crystallite size of ZrN and Zr2N phases increases by increasing the number of focus deposition shots. The residual stresses estimated for Zr (101), ZrN (111) and ZrN (200) phases are maximum in the nitrided surfaces at lower nitrogen ion dose, decreases as the nitrogen ion dose increases. The field emission scanning electron microscopy results exhibit the uniform and smooth film of zirconium nitride with granular surface morphology at 10 degrees angular position. The energy dispersive X-rays spectroscopy data indicate that nitrogen content in the film is improved for higher nitrogen ion dose while reduced at larger angular positions. The Vickers microhardness of the film is enhanced up to 400%. The microhardness increases by increasing the nitrogen ion dose and decreases rapidly by increasing the angular position. (C) 2008 Elsevier B.V. All rights reserved.