Description
Typical samples of CaB
6 are nonstoichiometric, i.e. the
ratio of boron to calcium is not exactly 6:1, for example
the ultra-fine powders of CaB
6 produced by some
researchers had B:Ca ratio of 5.91:1. It is an important
material due to its high electrical conductivity, hardness,
chemical stability, and melting point.
Chemical Properties
black cub; -200 mesh 99.5% pure; refractory material [KIR78] [CER91] [CRC10]
Physical properties
Calcium boride is a black,
lustrous, chemically inert powder with a low density.
Calcium hexaboride is insoluble in H
2O, MeOH (methanol),
and EtOH (ethanol) and dissolves slowly in acids.
It has the cubic structure typical for metal hexaborides,
with octahedral units of six boron atoms combined
with calcium atoms.
Uses
Carbon hexaboride is used in the manufacturing of
boron-alloyed steel. Also, calcium hexaboride is used
as a deoxidation agent in production of oxygen-free
copper, which results in higher conductivity than
conventionally phosphorus-deoxidized copper owing
to the low solubility of boron in copper. Also, it can serve as a high temperature material, surface protection, abrasives,
tools, and wear-resistant material.
Uses
Calcium boride is used as an electrode (cathode) material and n-type thermoelectric materials. It is used to make boron- alloyed steel, as a deoxidation agent in the production of oxygen-free copper. It is further used as an antioxidant in carbon bonded refractories. It acts as a new material which is used in the nuclear-industry for neutron- preventing, high-purity metal borid (TiB2,ZrB2,HfB2) and high-purity boron alloy(Ni-B, Co-B, Cu-b).
Preparation
Calcium boride can be formed directly from the
elements. Ca melts at 842°C and boron melts at
2076°C. Therefore, if a vapor of Ca metal at >850°C
(red-heat) is passed over crystals of boron, a gas–solid
reaction forms the desired boride. However, to obtain
stoichiometric compositions, it is better to heat the
well-mixed powders of Ca and B to obtain specific
compounds:
Ca+ 6B→CaB
6
Flammability and Explosibility
Not classified
