Temperature-Dependent Thermal and Chemical Stabilities as well as Mechanical Properties of Electrodeposited Nanocrystalline Ni

Nanocrystalline (NC) Ni electrodeposits (EDs) with a mean grain size of 34 ± 12 nm has been investigated, from room temperature to 800 °C under a purge gas of argon, by both non-isothermal and isothermal differential scanning calorimetry measurements, in combination with characterization of temperature-dependent microstructural evolution. A significant exothermic peak resulting from superimposition of recrystallization and surface oxidation occurs between 340 and 745 °C at a heating rate of 10 °C/min for the NC Ni EDs. The temperatures for recrystallization and oxidation increase with increasing the heating rate. In addition, recrystallization leads to a profound brittle–ductile transition of the Ni EDs in a narrow range around the peak temperature for the recrystallization.