Indium is often referred to as the "vitamin of alloys." Indium alloys can be used as soldering materials, and indium is an important new additive element for lead-free solders. The global trend towards lead-free solders is beneficial for the application of indium soldering alloys. The low melting point of indium alloys can also be utilized to produce special alloys, used in circuit breakers for fire protection systems and thermal control devices for automatic control systems; adding a small amount of indium to bearing alloys can extend their service life to 4-5 times that of conventional bearing alloys. Indium alloys are also used in dental, steel, and non-ferrous metal corrosion-resistant decorative parts, as well as in plastic metallization.

Due to its strong corrosion resistance and light-reflective properties, indium can be used to make mirrors on warships or passenger liners. Indium is sensitive to neutron radiation and can be used as a monitoring dose material in the nuclear energy industry. Currently, the amount of indium used in the nuclear energy industry is roughly comparable to its usage in the electronics industry.

Indium can act as an additive in lead-acid batteries and as an inhibitor in mercury-free alkaline batteries, making them environmentally friendly products. The usage of indium in preventing fogging layers is continuously increasing. Initially used in the automotive industry for its coatings, it may become widespread in industrial and civil construction. Sony Corporation of Japan has invented a new cathode that replaces scandium with indium, reducing the cost of each electron to about one-tenth of scandium-coated electrons. Consequently, indium's application in television high-power output and long lifespan is promising.

In the optoelectronics field, indium and its compound semiconductors have a wide range of applications. Among the III-V族 compound semiconductors based on indium, such as InSb, InP, and InAs, InSb was the earliest to be researched and applied. InP, however, is gaining attention and has promising applications, particularly in microwave to millimeter-wave communication, as a laser source for fiber-optic communication, and as a material for heterojunction solar cells, where it has made breakthroughs, showcasing the promising future of indium applications. InSb and InAs are also crucial in infrared detection and photomagnetic devices. In solar cells, indium compound thin films are emerging as a new force, attracting attention for their high conversion rates, low cost, and portability. Copper indium selenide (CIS) and other I-II-VI ternary compound thin film semiconductors, with their low cost, good performance, and simple processing, will become a significant direction for the development of solar cell industries in the future, driving the increased use of indium in this field. The new industry centered around information technology has emerged, with indium tin oxide (ITO) being a crucial material for all types of flat-panel displays. Currently, about 75% of the world's indium is consumed in this area, and there is still much potential for growth. Moreover, as the extraction and processing technologies for indium continue to advance and production costs decrease, the applications of indium are expanding further.

Indium is a silver-gray, extremely soft, fusible metal. Melting point: 156.61°C. Boiling point: 2060°C. Relative density: d7.30. Liquid indium can wet glass and will adhere to surfaces it contacts, leaving black stains.

Indium has slight radioactivity and consists of two main isotopes, In-113 being a stable nucleus and In-115 undergoing beta decay. Therefore, it is best to avoid direct contact during use.

Ingot indium, due to its strong light permeability and conductivity, is primarily used in the production of ITO targets (used for manufacturing LCDs and flat screens), which is the main consumption area for indium ingots, accounting for 70% of the total indium consumption.

The next few consumer sectors are: the electronic semiconductor field, accounting for 12% of consumption; the solder and alloy sector, also accounting for 12%; and the research industry, taking up 6%. Additionally, due to its softer nature, it is also used for filling gaps in industries requiring metal fill, such as vacuum gap filling materials at higher temperatures.

Medically, indium colloid is used for liver, spleen, and bone marrow scans. Indium-DTPA is used for brain and kidney scans. Indium-Fe(OH)3 particles are used for lung scans. Indium-Fe-ascorbic acid is used for placenta scans. Indium-bound transferrin is used for liver blood pool scans.

Gallium and Indium AlloysLiquid MetalThe material forms a solid solution alloy that can become liquid at room temperature, with a surface tension of 500 millinewtons per meter. This means that, without external force, when the alloy is placed on a flat surface, it maintains an almost perfect spherical shape. Upon the application of a small current, the surface tension of the sphere decreases, and the metal spreads out on the surface. If the charge is reversed from negative to positive, the liquid metal reverts to a spherical shape. Adjusting the voltage can also modify the metal's surface tension and viscosity, allowing for different structural transformations. This research can also be applied to help repair severed human nerves, preventing long-term disability. Researchers claim that this breakthrough aids in the construction of circuits and self-healing structures.