Additionally, black
nickel-plated surfaces are highly resistant to rust and corrosion, which makes
them ideal for outdoor applications where exposure to moisture is likely. A
new, metastable nickel boride, Ni7B3, is trapped by applying low-temperature
solution synthesis. Its crystal structure is an unknown, disordered variant of
the Th7Fe3-structure type, solved from synchrotron X-ray powder data. Magnetic
measurements reveal paramagnetism, which is under quantum chemical
calculations. According to high-temperature X-ray diffraction and differential
scanning calorimetry, this nickel boride phase has a narrow stability window. Nickel
boride (Ni’B) was obtained as a powder (average particle size of 0.5 p,m and
specific surface area of 9 m2 g-‘) (7) by reduction of nickel acetate with
NaBH4 in aqueous NaOH (9). The electrodes were obtained by pressing the
particles atp = 120 NIPa at room temperature. Silver epoxy (EPO-TEK H20E, Epoxy
Tech., Inc) was used to ensure a good electricalcontact. One face and the sides
of electrodes were coated with Epofix resin (Struers), known for its stability
(i.e., no leaching) in alkaline solution (10- 12), in order to obtain
aprojectedgeometric surface area of 1.1 cm’ and avoid the effect of the edge
plane defects. This work developed a synthesis route of Ni3B, an attractive
material for making heating elements and a promising catalyst component, using
high-energy ball milling of nickel and boron powder mixtures. The milling
duration was varied from 1 to 15 min. Ball milling led to the partial
dissolution of boron in the crystalline lattice of nickel and the crystallite
size refinement of nickel. Heating of the ball-milled mixtures at a constant
rate led to the thermal explosion, the indications of which were a rapid
temperature rise and the formation of boride phases. The duration of ball
milling was shown to influence the phase composition of the products of thermal
explosion. The time of milling ensuring the formation of single-phase Ni3B was
determined to be 7 min. The ignition temperature of the thermal explosion
decreased with the milling time: a more than 300 °C decrease was observed for
the mixture milled for 15 min relative to the non-milled mixture. The maximum
temperature developed during the thermal explosion increased in the mixture
milled for 1 min relative to the non-milled mixture. Then it decreased with the
milling time, reaching the level of the non-milled mixture after 15 min of
milling. The observed dependence of the maximum temperature on the milling time
is related to the net effect of mixing uniformity improvement between the
reactants and a partial transformation of the reaction mixtures into Ni(B)
solid solutions and Ni3B during milling. The proposed synthesis route of a
single-phase Ni3B powder has the advantages of short processing time and low
energy consumption. If you are looking for
high quality, high purity and cost-effective Nickel boride, or if you require
the latest price of Nickel boride, please feel free to email contact mis-asia.
