Effect of Heat Treatment on Diffusion Behavior of Hydrogen in Nickel Films Electrodeposited from Watt’s Solutions with and without Thiourea

Ni films electrodeposited from Watt’s solutions with and without thiourea addition were heat-treated to evaluate the diffusion behavior of hydrogen in the films. Hydrogen permeation measurements were taken using the Devanathan–Stachurski double cell technique. Regardless of whether thiourea was added or not, the crystal grain size of the deposited Ni films increased to several tens microns with heat treatment for 10 min at 800°C. Heat treatment of Ni films deposited with thiourea resulted in the segregation of sulfur at the grain boundaries. The hydrogen permeation rate through the deposited Ni films significantly decreased with increasing grain size due to heat treatment, regardless of whether thiourea was added. The segregation of sulfur at the grain boundaries further reduced the hydrogen permeation rate.