1. The feasibility has been demonstrated of producing composite Ni-B electrodeposits with a uniform distribution of boron particles throughout their matrix. 2. Diffusional annealing leads to the formation of qualitatively new structures in such deposits and improves their physicomechanical characteristics. 3. The wear resistance of heat-treated Ni-B deposits is as high as, and frequently much higher than, that of hard chromium electrodeposits.