ABSTRACT

Industrial copper particles (D50 = 75 μm) were used as received. The mixture solution of copper nitrate [Cu(NO3)2] and magnesium nitrate [Mg(NO3)2] were utilized to form the precursor. The mole ratio of Cu(NO3)2 to Mg(NO3)2 was 1:1. The Ni(OH)2/ Mg(OH)2/Cu colloid was obtained by using the chemical co-precipitation method. Then, the mixture colloid was vacuum thermal treated for 8 h at 90 °C, which was then crushed into fine powder using a mortar. The obtained solid powders contained 7 wt% of the Ni catalyst. The CVD process was executed at atmospheric pressure in a horizontal alumina tube reactor that was connected to N2 and CH4 gas cylinders. About 500 mg of 7 wt% Ni/ Cu catalyst was taken in a quartz boat and placed in the middle of the alumina tube as a reactor zone. Before 400°C, the heating rate was controlled at 5 °C/min and N2 was introduced as the protection

1 INTRODUCTION

For surface engineering applications such as electrical contact materials, investigated materials with high performance usually need to meet the following requirements: excellent electrical conductivity, low interception, etc.[1] However, it was difficult for pure metals or alloys to meet structure requirements. An electrical contact material was composed of a matrix phase and a reinforcement phase. The matrix material was made up of copper/ silver metal, which exhibited excellent performance in terms of high thermal conductivity, low contact resistance, etc.[2] The reinforcement phase was composed of metal or compound or ceramics particles. The copper matrix was widely applied for electrical contact materials due to their electrical and thermal properties. Recently, CNTs were extensively researched, thanks to their superior mechanical properties and heat transfer performance.[3] More number of studies focused on CNTs/Cu composites.[4-5] However, density differences would result in heterogeneous distribution of above-mentioned two-phase materials. In this paper, the synthesis of Ni/MgO nanoparticles on the Cup surface by using the co-deposition method is discussed. The focus of this work is on fabrication for uniform growth

gas. The N2 gas flow rate was 400 SCCM. Within the range of 400 °C-670°C, H2 gas was applied as the reduction gas. The gas flow rate was found to be 150-250 SCCM. After reaching 670 °C, N2 and methane began to purge to produce CNTs. During the reaction process, the gas flow ratio of N2 to CH4 was 1:1. Once the reaction was completed, methane flow was discontinued and N2 flow continuously purged the reaction chamber till room temperature was attained. The collected product was subjected to purification.