Pro glove box workstation

Elemental Mg metal powders (~80 μm, 99.8% provided by Alfa Aesar - USA), and hydrogen gas (99.999%) were used as starting materials. An amount of 5 g Mg was balanced inside a He gas atmosphere (99.99%) - glove box (UNILAB Pro Glove Box Workstation, mBRAUN, Germany) and sealed together with fifty balls (11 mm in diameter) made of pure Ni metal (99.9 wt.%) provided by Wako, Japan (item# 144-07255, Lot # DPR1504) into a hardened steel vial (150 ml in volume), using a gas-temperature-monitoring system (GST; supplied by evico magnetic, Germany). The ball-to-powder weight ratio was maintained at 40:1. However, in a parrel experiments Cr-steel balls (11 mm in diameter), using the same ball-to-powder weight ratio, were used as milling media under the same experimental conditions. The vial was then evacuated to the level of 10⁻³ bar before introducing H₂ gas to fill the vial with a pressure of 50 bar. The reactive ball milling (RBM) process was carried out at room temperature, using a high-energy ball mill (Planetary Mono Mill PULVERISETTE 6, Fritsch, Germany). The RBM process was interrupted after selected milling time (3, 6, 12.5, 25, 50, 100 and 200 h) where the vial was opened inside the glove box to take a small amount (~300 mg) of the milled powders for different analysis. Then, the RBM process was resumed, using the same operational conditions shown above.

Pure Zr (100 μm, 99% purity), Ni (10 μm, 99.9% purity) and Pd (10 μm, 99.5% purity) metal powders provided by Alfa Aesar - USA, were used as starting alloying elements. The powders were balanced and manually mixed inside a helium (He) gas atmosphere (99.99%)-glove box (UNILAB Pro Glove Box Workstation, mBRAUN, Germany) to give the starting charge (1 g) with an average nominal composition of Zr₇₀Ni₂₀Pd₁₀. The powders were then sealed together with five Cr- stainless steel balls (10 mm in diameter) into a FeCr steel vial (20 ml in volume, Retsch, Germany), using a ball-to-powder weight ratio as 50:1. In order to avoid the agglomeration of the metallic powders during the ball milling process, a cryo-mill system provided by Retsch was used. In this experiment, the vial containing the balls and powders was mounted on the cryo-milling system where the process taking place under continuous cooling, using liquid nitrogen flow. The liquid nitrogen circulated through the system and was continually replenished from an auto fill system in the exact amount, which is required to keep the temperature at −196 °C. This milling process was carried out with a frequency of 25 Hz for 25 h. The end-product obtained after 25 h was discharged in the He-atmosphere glove box.

High purity elemental powders of Co (150 μm, >99.9 wt%, #266647: Sigma-Aldrich, St. Louis, MO, USA), Ti (45 μm, >99.99 wt%, #366994: Sigma-Aldrich), and B (45 μm, >98 wt%, #GF47837065: Sigma-Aldrich) were used as the starting feedstock materials. The powders were handled, balanced, and then mixed inside the He-atmosphere (99.99%) glove box (UNILAB Pro Glove Box Workstation, mBRAUN, Garching, Germany) to get an amount of 25 g with the desired nominal composition of (Co₇₅Ti₂₅)_100−xB_x (x: 2–30 at%).