Electroforming of Copper/ZrB₂ Composites Coatings and Its Performance as Electro-Discharge Machining Electrodes

Abstract

Copper electroforming, together with rapid prototyping (RP) technology, provides a method for manufacturing EDM electrodes rapidly. However, the use of conventional electroformed copper electrodes is restricted because of the high electrode wear rate in EDM processes. This paper presents a study on the electroforming technique of copper/zirconium diboride (ZrB2) composite coating and its performance as an EDM electrode. Cu-ZrB2 composite coating is electroformed from a copper nitrate bath containing micro-sized ZrB2 particles in such a way that by varying the process parameters, ZrB2 particles approximate to 20 Vol.% are incorporated in the coatings. Analyses by optical microscopy and scanning electron microscopy reveal that ZrB2 particles are uniformly dispersed in the copper matrix and the grains of the coating are refined due to the incorporation of ZrB2 particles. The electroformed coatings deposited on copper substrates with approximately 1mm thickness are used as electrodes. EDM experiment shows that performance such as the spark-resistance of the new electrodes is improved compared with that of conventional electroformed copper electrodes because the incorporation of refractory particles in the copper matrix as well as the refinement of the grains of the coating, and the. Cu-ZrB2 composites show good performance in finish machining condition.

Characterization of copper–silicon nitride composite electrocoatings

“…The Si 3 N 4 particles inhibited the growth of the copper crystallites and the composite coatings have a copper matrix with smaller crystal sizes comparatively to the pure copper deposits. This was also observed for other copper composites, such as Cu-ZrO 2 [11], Cu-ZrB 2 [13], and Cu-Al 2 O 3 [18].…”

“…Nevertheless, these coatings show low mechanical and wear resistance. Aiming to modify the properties of electrolytic copper, particles of ceramic materials, Al 2 O 3 [3][4][5][6][7][8], TiO 2 [9,10], ZrO 2 [11], SiC and MoS 2 [6], metallic materials or intermetallics, Cr [12] and ZrB 2 [13,14], polymeric materials, poliacrilonitrile (PAN) [15] and also graphite [6], carbon nanofibers [16], and microcapsules containing lubricants [17] were incorporated to copper. The effect of particle incorporation on the copper coating properties was shown to be positive or negative depending on the electrolysis parameters employed and the type and characteristics of particles.…”

Refractory Diborides of Zirconium and Hafnium

“…[2][3][4] Some structural, physical, transport, and thermodynamic properties of ZrB 2 and HfB 2 are summarized in Table I. [5][6][7][8][9][10][11][12] Applications that take advantage of these properties include refractory linings, [13][14][15] electrodes, [16][17][18] microelectronics, 19 and cutting tools. 20 In addition to high melting temperatures, ZrB 2 and HfB 2 have a unique combination of chemical stability, high electrical and thermal conductivities, and resistance to erosion/ corrosion that makes them suitable for the extreme chemical and thermal environments associated with hypersonic flight, atmospheric re-entry, and rocket propulsion.…”

Electrodeposition and characterization of Cu–Nb composite coatings

“…In order to improve or modify the properties of copper coatings, particles of ceramic [3][4][5][6][7][8][9][10][11][12], metallic or intermetallic [13][14][15] and polymeric materials [16] were incorporated to copper.…”