Neutron inelastic scattering measurements have been done on amorphous Pr 16.7 Ni 83.3 and crystalline PrNi 5 after different steps of heat treatment of the samples. The magnetization, the heat capacity in magnetic fields up to 80 kOe, and the crystallization of the amorphous samples have also been studied. The magnetic contribution to the neutron inelastic scattering and to the heat capacity has been separated from the contributions due to phonons and has been analyzed for the amorphous samples. The magnetic excitation spectra of the Pr 3ϩ ground state J multiplet in the amorphous and the polycrystalline samples show strong qualitative differences: a broad and low energy ͑ϳ1 meV͒ peak in the amorphous samples instead of narrow crystal field excitations in the same samples after crystallization. The magnetization curves of the amorphous sample proved to be nonlinear at temperatures lower than 20 K and evidence for a transition to ferromagnetic correlations in the amorphous samples is given. A nearly stepwise transition from the disordered to the ordered crystalline local structure is observed in the neutron scattering experiments done with samples after annealing at different temperatures. The phenomenological model of a deformed crystal has been worked out in order to interpret all experimental data consistently. ͓S0163-1829͑96͒09529-X͔ S M ͑ Q, ͒ϭ 1 4 ͩ 1.91e 2 m e c 2 ͪ g J 2 F 2 ͑ Q ͒ ϫ ͚ i j ͉͗i͉J Ќ ͉ j͉͘ 2 j ͑T͒␦͑E i ϪE j Ϫប͒, ͑2͒