Influence of ambient pressure on the pore structure feature of porous nickel and its adsorption performance for Ti-based getters using dynamic hydrogen bubble templating (DHBT) method

The DHBT method is widely used for the preparation of metallic porous materials. However, the porous metals prepared by this method have many disadvantages, such as: large average pore diameter, wide pore distribution and low pore density, which limit the method's application. In this study, low-pressure electroplating was introduced into the DHBT process, guided by gas solubility and liquid-phase mass transfer theories. By adjusting bubble desorption time, improving current distribution uniformity, and enhancing mass transfer at the cathode surface, the controllable preparation of porous nickel with an optimized pore structure was achieved. Results show that low-pressure porous nickel has smaller average pore sizes, higher pore densities, and better pore consistency compared to those prepared at atmospheric pressure. The average pore size at 40 kPa is only 43 % of that at atmospheric pressure, with pore density and specific surface area (SSA) increased 3.5 and 1.4 times, respectively. Additionally, the adsorption performance tests revealed that the porous nickel at 40 kPa had the highest initial adsorption rate, about 3 times that of atmospheric pressure, but the adsorption capacity did not differ much, perhaps that the adsorption capacity mainly depends on the thickness of the getter when the getter layer is thin.