Magnesium (Mg) particles and nano-morphologies such as nanowires have been prepared via physical vapor deposition (PVD) in a wire wound single zone tube furnace for the
purpose of optimising the preparation of magnesium prior to hydrogen storage. 

Furnace temperatures, T\(_f\) = 700 – 1000 ⁰C and argon flow rates, Q\(_A\)\(_R\) = 100 – 300 cm\(^3\).min\(^-\)\(^1\) are studied. It is found that both variables influence the deposition temperature (T\(_d\)).

A temperature gradient is studied by taking thermocouple-probe readings at measured positions from the furnace heater to the exit end of the tube for the range experimental parameters. Subsequent substrate placement at these positions is used as a means of natural T\(_d\) control, and an innovative ‘one-piece multiple-substrate’ is used to capture several deposits per PVD experiment.

Results show that T\(_d\) and morphology are strongly correlated. T\(_d\) = 600 - 700 ⁰C shows dominance of favourable morphologies and T\(_d\) = 80 – 140 ⁰C shows coexistence of particles and nano-morphologies. An intermediate T\(_d\) = 312 - 342 ⁰C shows homogeneous particles with completely clean surfaces in what is proposed to be an endothermic property of Mg. Stainless steel, roughened stainless steel and single crystal silicon are used and highly dense nanowires have been produced.