Producing nickel highly porous materials by electrodeposition

The article presents studies on a possibility of producing highly porous cellular materials (HPCM) from nickel using electroplating by copying a polymer matrix from polyurethane foam. To get more uniform thickness of structures, it has been determined to use an intermittent deposition mode with leveling agents. It has been found that to produce nickel-based porous materials after annealing a polymer frame average thickness of a nickel coating should be 30–40 μm or more. Uniformity was assessed by comparing coating thickness in depth and on the surface of metallic HPCM. By comparing these two values, we can make a conclusion about uniformity in percentage. Studies on electrical deposition of nickel on HPCM have showed that it is rather difficult to maintain current density constant, factoring into a branched structure of the surface on HPCM along width, depth and height; besides, there are concentrated difficulties with delivery of nickel ions in depth of HPCM. Therefore, electrolysis is conducted at DC bath voltage, contributing to more uniform coatings along a total volume of HPCM. The use of a pulse (intermittent) mode of electrical deposition showed a significant improvement of performance: at a delay of 0.2 s and a pulse duration of 1 s metal is significantly better distributed at a bath voltage of 4.7 V. To get the set coating thickness (60 μm on average), the electrolysis duration increases almost insignificantly. The article proposes the following composition of the electrolyte for nickel plating, g/l: 175 nickel sulfate; 20 nickel chloride; 30 amber acid; 2 saccharin; 0.1 azodye. The article contains electrolysis parameters for producing nickel-based HPCM.