The Ni-P-based ternary coating with a third element, including Cu, Cr and W, is fabricated by the RF magnetron sputtering. It is revealed that the P/Ni ratio and the amount of the third element in the ternary coating can be controlled through power adjustment and target design during sputtering. All the ternary coatings exhibit an amorphous microstructure in the as-deposited state. Mechanical properties, including microhardness and scratch behavior are characterized and analyzed with respect to the concentration of the additional element as well as the thermal history in the following heat treatment. It is observed that the hardness of the coatings can be effectively modified with the composition control of the third elements. Possible embrittlement caused by the third elements through scratch test is also discussed. (C) 2003 Elsevier B.V. All rights reserved.