อินเดียมฟอยล์ is a thin sheet of indium, a chemical element with the symbol ‘In’ and
atomic number 49, known for its exceptional physical and chemical properties. Indium
is part of group 13 on the periodic table and is characterized by its softness, high
plasticity, malleability, ductility, and remarkable corrosion resistance to water and
alkalis, making it highly versatile for various industrial applications. Its ability to
remain soft and workable at very low temperatures is particularly advantageous for
specialized equipment operating near absolute zero, such as cryogenic pumps and
high vacuum systems.
The production of indium foil is intricately linked to the processing of sulfidic zinc ores,
where อินเดียม is primarily found. This process involves multiple steps, including raw
material inspection, precise cutting, and stringent quality control to ensure high purity
and consistency. China leads global indium production, followed by South Korea
and Japan, collectively accounting for the majority of the world’s indium supply.
The market for indium has experienced fluctuations due to its by-product nature
and the dynamics of primary metal markets, but advancements in refining and
recycling technologies have helped maintain a stable supply to meet growing global
demand.
Indium foil is significant in various industries, including electronics, aerospace,
energy, and healthcare. It is essential in the manufacture of flat panel displays, solar
cells, and semiconductors. The electronics industry, in particular, relies heavily on
indium for components such as transistors, diodes, and LEDs, as well as for thermal
interface materials due to its excellent thermal conductivity and ability to conform to
irregular surfaces. Additionally, indium’s “stickiness” enhances its performance
in soldering applications, making it a crucial material in producing reliable, void-free
joints in electronic assemblies.
Despite its benefits, the handling of indium requires careful safety measures due to
potential health risks associated with its compounds, which can affect the kidneys
and pulmonary systems. Proper ventilation, protective clothing, and adherence to
safety protocols are essential to mitigate these risks. The ongoing need for indium,
driven by its unique properties and critical role in high-tech applications, has led
to significant demand and price fluctuations. Nonetheless, improved recycling and
manufacturing efficiencies continue to support a balanced supply and ensure that
indium remains available for its diverse applications.
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อินเดียม is characterized by its softness, high plasticity, malleability, and ductility,
making it a versatile material for various applications. The Indium metal is known for
its remarkable corrosion resistance to water and alkalis, adding to its durability in
different environments.
One of the most significant attributes of indium is its capacity to remain soft and
workable even at very low temperatures, which is highly beneficial for specialized
equipment operating near absolute zero. This unique property is particularly
valuable for cryogenic pumps and high vacuum systems, as well as other unique joining
and sealing applications.
The melting point of indium is 156.6°C (313.9°F), while its boiling point is 2072°C
(3762°F). Despite its relatively low melting point, indium’s boiling point is higher
than that of thallium but lower than gallium, which deviates from the general trends
observed in the melting points of other post-transition metals. This deviation can
be attributed to the weakness of the metallic bonding, as indium has few delocalized
electrons.
อินเดียม also exhibits excellent thermal conductivity, measured at 86 W/mK, which is
significantly higher than polymer-based thermal interface materials. Its ductility and
compressibility make it an ideal thermal interface material, effectively bridging gaps
and ensuring efficient heat transfer between components.
In terms of its interaction with other materials, indium is known for its “stickiness,”
which allows it to adhere tightly to itself and to other metals. This property enhances
its usefulness in soldering applications, where it can reduce the melting point of
solders, strengthen them, and prevent breakdowns under thermal stress. Indium’s
ability to conform to irregular surfaces further extends its applicability in various
technological and industrial contexts.
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Indium is not very reactive and does not form compounds with water. When it
reacts with halogens, it produces indium(III) compounds. Despite its general lack
of reactivity, indium can oxidize when exposed to stronger oxidizing agents such as
halogens. It is noteworthy that indium does not react with bases and is insoluble
in alkaline solutions.
In terms of its oxidation states, indium typically exists in the +3 state, although it
can also be found in the +1 and +2 oxidation states under specific conditions.
The +3 oxidation state is predominant and is commonly seen in compounds such as
indium(III) oxide (In2O3) and indium(III) chloride (InCl3). Indium compounds in the
+2 oxidation state are less frequent but do exist and often feature In–In bonding.
Upon burning in air, indium forms indium oxide (In2O3), a compound that can
react with both acids and bases, exhibiting amphoteric properties. This oxide
is an important component in several industrial applications, including its use in
semiconductors and touch screens.
Indium also has interesting coordination chemistry, forming complexes with ligands
that can donate electron pairs due to its empty d-orbitals. These complexes
are studied for potential applications in catalysis and other specialized chemical
processes.
นอกจากนี้, อินเดียม does not form borides, silicides, or carbides, and its hydride InH3
is highly unstable, existing only transiently in ethereal solutions at low temperatures
before spontaneously polymerizing. The element shows basic behavior in aqueous
solutions, exhibiting only slight amphoteric characteristics.