Preparation of Ni–Cr alloy foams by electrodeposition technique

Metallic foams have many applications in industry and are made using various methods. However, no suitable method for heating Ni–Cr alloy foam has been available. A method of preparing Ni–Cr alloy foam by an electrodeposition technique is described in the present paper. The method includes the following steps: establishing electrical conductivity of organic foam; electroplating of a Ni layer; electroplating of a Cr layer; eliminating the organic matrix and a homogenisation heat treatment. The plating solutions and process parameters of electrodeposition are introduced in detail. Homogenisation of the samples was carried out in a sealed quartz tube at 1100°C and the homogenisation time was determined by experiment and calculation. Experimental results are shown indicating that the Ni–Cr alloy foam made by this electrodeposition technique had a three-dimensional reticulated structure and formed a single phase Ni based solid solution. Also, the apparent resistivity was measured and it is demonstrated that the higher resistivity of the foam gave it good electrical heating properties.