Preparation of nickel porous materials by sintering nickel oxalate and sodium chloride after blending and reduction

Abstract

In this paper, sodium chloride(NaCl) was used as the separator agent and the pore-forming agent. Nickel porous materials were prepared by sintering nickel oxalate(NiC2O4) and NaCl after blending and reduction. The pore micro morphology, porosity, pore size, pore size distribution and permeability coefficient of nickel porous materials at different sintering temperatures were studied. The results show that NaCl as a separator can effectively prevent numerous direct contacts between the initial nickel particles and then reduce the sintering agglomeration during the process of blending. Thus, uniformly mixed fibrous nickel powders and NaCl powders are prepared. Nickel porous materials prepared by sintering nickel oxalate and NaCl after blending and reduction have a pore structure composed of lapped pores between the fibrous nickel particles and the prefabricated pores formed by the pore-forming agent. By changing the sintering temperature, the porosity and pore structure characteristics of the materials can be well controlled, and the nickel porous materials with good pore properties are obtained. When the sintering temperature increases from 450 °C to 650 °C, the open porosity is 71.7 % ∼ 79.5 %, the average pore size is from 0. 519 μm ∼ 1.043 μm, and the permeability is from 0.076×10−12 m2 ∼ 0.19×10−12 m2. The pore size distribution shows three peaks at low sintering temperatures. The distribution gradually turns into a double peak and eventually tends to a single peak as the sintering temperature increases.