[en] Ni nanoparticles were grown on a n-Si(111) substrate by using pulsed electrodeposition in a non-aqueous NiCl₂ + methanol solution. In this solution, the Ni/Si interface showed rectifying characteristics due to the formation of a Schottky barrier, and the reduction of Ni²⁺ was the dominant process rather than the oxidation. We confirmed that the average size of the Ni nanoparticles obtained by using pulsed electrodeposition depended on the frequency of the applied potential pulse. When the frequency was varied from 20 Hz to 900 Hz, the average size of Ni nanoparticles varied in the ranges from 48 nm to 130 nm. In the case of 600 Hz, the Ni nanoparticles were found to undergo a 3-dimensional instantaneous nucleation followed by diffusion-limited growth. Vibrating sample magnetometer (VSM) measurements showed that the coercivity of the as-deposited samples depended significantly on the size of Ni nanoparticles. The coercivity of the Ni nanoparticles increased up to an average size of 86 nm, and a maximum coercivity of 203.5 Oe was obtained at an average size of 86 nm. Above this value, the coercivity began to decrease again and was 96.3 Oe at an average size of 131 nm.