Ni-P coatings were prepared by autocatalytic technology and their morphology and anticorrosive capacity were studied based on their phosphorus content. Acid and basic baths were operated; each one produced different phosphorus contents. The protective power increased with the phosphorus concentration. The coatings were evaluated by polarization measurements. In acid environment the coating (7,9% P) presented a smooth feature and in basic environment the coating (2,6% P) presented a nodular feature. Also, speed of deposition and thickness of layer were measured.