Abstract: Ni-coated TiC composite powders were synthesized by ultrasonic-assisted electroless plating process with non-noble metal activation pretreatment at room temperature． The growth mechanism of Ni layer，surface morphology and composition of as-received TiC powders，pretreated TiC powders and Ni-coated TiC powders were analyzed by field emission scanning electron microscopy ( FE-SEM ) ，and energy dispersive spectrometry ( EDS ) ． The results show that the uniformly Ni-coated TiC composite powders are successfully synthesized by ultrasonic-assisted electroless plating at room temperature without convertional sensitization and activation steps，and the Ni layers with cell structure are denely and uniformly distributed on the TiC powders． The growth mechanism of Ni layers is as follows: the step-like defects which act as activated sites form on the surface of TiC powder particles after pretreatment，and the reactants in the plating solution are adsorbed on the activity surface and oxidation-reduction reaction occurs to deposit out Ni particles． The stripy Ni particles are nucleated，and then grow up and tangle into cellular structure and finally aggregate into layer．
Key words: non-noble metal activation pretreatment; electroless plating; Ni-coated TiC powders; growth mechanism
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