Application introduction
At present, the consumption areas of gallium metal in my country include semiconductors and optoelectronic materials, solar cells, alloys, medical equipment, magnetic materials, etc. Among them, the semiconductor industry has become the largest consumption area of gallium, accounting for about 80% of the total consumption. With the rapid development of gallium's downstream application industries, especially the semiconductor industry and solar cell industry, the demand for metallic gallium will also grow steadily in the future.
Semiconductor field
In the field of semiconductor materials, gallium arsenide (GaAs) is the most widely used material and the technology is the most mature. Semiconductor materials serve as carriers of information dissemination, and their usage of gallium accounts for 80% to 85% of the total gallium consumption. Mainly used in the field of wireless communications, gallium arsenide power amplifiers can increase communication transmission speeds to 100 times that of 4G networks, playing an important role in entering the 5G era [2]. And because of its thermal properties, low melting point, high thermal conductivity and good flow properties, gallium can be used as a heat dissipation medium in semiconductor applications. Gallium metal is used in thermal interface materials in the form of a gallium-based alloy. It can improve the heat dissipation capacity and efficiency of electronic components.
Solar battery
The development experience of solar cells has evolved from early monocrystalline silicon solar cells to polycrystalline silicon thin film cells. Due to the high cost of polycrystalline silicon thin film cells, researchers discovered copper indium gallium selenide (CIGS) thin film cells among semiconductor materials [3]. CIGS Batteries have the advantages of low production costs, the ability to be produced in large batches, and high photoelectric conversion rates, so they have broad development prospects. Secondly, the conversion efficiency of gallium arsenide concentrator solar cells has obvious advantages over thin film cells made of other materials. However, due to the high production cost of gallium arsenide materials, it is currently mainly used in the aerospace and military fields.
Hydrogen energy
As awareness of the energy crisis increases around the world, people are seeking to replace non-renewable energy sources, among which hydrogen energy stands out. However, the high cost and low safety of hydrogen storage and transportation hinder the development of this technology. Aluminum as The most abundant metal element in the earth's crust can react with water to produce hydrogen under certain conditions. It is an ideal hydrogen storage material. However, the surface of metallic aluminum is easily oxidized to form a dense aluminum oxide film, which inhibits the reaction. According to researchers It was found that metal gallium with a low melting point is alloyed with aluminum, and gallium can dissolve the aluminum oxide coating on the surface, allowing the reaction to proceed [4], and the metal gallium can be recycled and used repeatedly. The use of aluminum gallium alloy materials greatly solves the problem of rapid preparation, safe storage and transportation of hydrogen energy, and improves safety, economy and environmental protection.
medical field
Gallium is mostly used in the medical field because of its unique radioactive properties, which can be used to image and inhibit malignant tumors [5]. Gallium compounds have obvious antifungal and antibacterial activities, and ultimately achieve the purpose of sterilization by interfering with bacterial metabolism. And gallium alloys can be used to make thermometers, such as gallium indium tin thermometers, a new type of liquid metal alloy that is safe, non-toxic and environmentally friendly and can be used to replace toxic mercury thermometers. In addition, a certain proportion of gallium-based alloys replace traditional amalgam and are used as new dental filling materials for clinical applications.
Alloy field
Gallium and indium, thallium, tin, bismuth, zinc, etc. can form a series of low-melting alloys between 3℃ and 65℃, which are used for temperature measurement and control, mercury substitutes in instruments, supports in bead setting operations, and metal coatings. cooling circuits in the layer, electronics and nuclear industries. For example, gallium alloy containing 25% indium is a low melting point alloy that melts at 16°C and can be used in automatic fire extinguishing devices. Gallium and copper, nickel, tin, gold, etc. can form a cold flux, which is suitable for special-shaped thin walls that are difficult to weld, cold welding and cavity plugging between metals and between metals and ceramics.
Other uses
In the atomic energy industry, gallium can be used as a thermal conductive material to conduct heat out of reactors. In addition, gallium can also absorb neutrons, thereby controlling the number of neutrons and the reaction speed.
Gallium iodide is used in high-pressure mercury lamps and gallium can also be used to make cathode vapor lamps. Adding gallium iodide to a high-pressure mercury lamp can increase the radiation intensity of the mercury lamp.
Because gallium has the property of "thermal contraction and cold expansion", it has good castability and can be used to make lead type alloys to make the fonts clear.
Gallium has a very low vapor pressure and can be used as a sealing fluid in vacuum devices.
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