Surface and Coatings Technology 183 (2004) 247–253 0257-8972/04/$ - see front matter  2003 Elsevier B.V. All rights reserved. doi:10.1016/j.surfcoat.2003.08.085 Composite plating of Ni–P–Al O in two steps and its anti-wear 23 performance Nabeen K. Shrestha, Dambar B. Hamal, Tetsuo Saji* Department of Chemistry and Materials Science, Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro-ku, Tokyo 152-8552, Japan Received 14 April 2003; accepted in revised form 28 August 2003 Abstract A composite coating of Ni–P–Al O containing 50.0 vol.% of dispersed alumina particles along with approximately 8.9 wt.% 23 (23.4 vol.%) of phosphorus into a nickel matrix was prepared by the proposed ‘Two-Step’ technique. This technique involves the electrophoretic deposition of a uniform film of alumina particles on a Ni–P-coated copper substrate in the first step followed by the electroless nickel deposition in the second step. The particle incorporated composite coatings exhibited the better anti-wear performance than the particle-free coatings. Heat treatment of these coatings deposited from an electroless bath showed the increased wear resistance of the coating due to the crystallization of hard Ni P alloy from the amorphous Ni–P meta-stable phase. 3 However, the referenced electrodeposited coatings exhibited the better anti-wear performance than the electrolessly deposited corresponding coatings in the present investigation.  2003 Elsevier B.V. All rights reserved. Keywords: Composite; Electroless; Plating; Nickel; Alumina; Wear 1. Introduction Ever since the first development of composite mate- rials, the goal has been to achieve a combination of properties not achievable by any of the elemental mate- rials acting alone. A combination of dissimilar materials could produce a composite solid with wide mechanical, chemical, electrical, magnetic and optical properties. However, these properties depend upon the contribution from the distributed and the matrix phases of a compos- ite material. The metal matrix composites containing ceramic particles as a distributed phase find a lot of applications especially in the field of engineering works as anti-wear and anti-frictional materials w1x. There are a number of methods to prepare the particle-dispersed metal matrix composites w2x. However, the most com- mon method is the composite plating. The incorporation of particles into a metal matrix by this method is based on the electro- w3x and electroless w4x plating technique. Since ceramic particles in a particle-dispersed metal matrix composite act as a load-bearing element, a high volume percent of these particles in the composite *Corresponding author. Tel.yfax: q81-3-5734-2627. E-mail address: tsaji@o.cc.titech.ac.jp (T. Saji). coating is desirable. Therefore, in an attempt to disperse a high volume percentage of particles in a metal matrix, various cationic surfactants have been used in the plating bath w5,6x. In this regard, recently we have shown that the redox- active cationic surfactant having more positive redox potential than that of the metal being plated acts as a powerful promoter for particle codeposition w7,8x. How- ever, this action of a surfactant depends upon the interaction among particles, surfactant and electrodes. Therefore, a particular surfactant can be used for enhanc- ing the codeposition of only a limited type of particles. In order to overcome this difficulty, recently we have reported a simple technique for incorporating a high volume percent of various ceramic particles into nickel matrix in two steps w9x, and we have demonstrated that these composite coatings had a better anti-wear perform- ance than the composite coatings prepared by the clas- sical technique of single-step composite plating. However, a close control of pH of the bath is needed in this method and it is tedious to find out the electrolysis potential of the second step. Moreover, it took several hours of electrolysis time to prepare these composites. Therefore, in order to overcome these problems, electro-