Understand the properties and uses of gallium in one minute

The properties of metal gallium: element symbol Ga, atomic number 31, is a group IIIA metal. The density is 5.904 g/cm³, the melting point is 29.76 degree (302.91 K, 85.57 degree F), and the boiling point is 2204 degree (2477 K, 3999 degree F). Solid gallium is blue-gray, and liquid gallium is silver-white. Gallium is hard and brittle at low temperature, but melts when it exceeds room temperature, soluble in acid and alkali, slightly soluble in mercury, and highly corrosive. Gallium is relatively stable in dry air, and an oxide film will form on the surface to prevent continued oxidation, and it will lose its luster in humid air. The freezing point of gallium is very low. When it is converted from liquid to solid, the expansion rate is 3.1 percent . Gallium can infiltrate glass, so it should not be stored in glass containers, but in plastic containers.

Occurrence state of gallium: The content of gallium in the earth's crust is 0.0015 percent . The distribution of gallium in nature is relatively scattered, and most of them exist in associated minerals, mainly in bauxite, and a small amount in tin, tungsten and lead-zinc.

Use of gallium: At present, the consumption fields of metal gallium 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 field of gallium, accounting for about 80 percent of the total consumption. With the rapid development of the downstream application industry of gallium, especially the semiconductor industry and solar cell industry, the demand for metal gallium will also grow steadily in the future.

1.1 Semiconductor Materials

Gallium is a rare metal with a low melting point and a high boiling point, and is known as the "backbone of the electronics industry". Gallium compounds are high-quality semiconductor materials and are widely used in the optoelectronics industry and microwave communication industry for the manufacture of microwave communication and microwave integration, infrared optics and infrared detection devices, integrated circuits, light-emitting diodes, etc. For example, the red and green light we see on computers is emitted by gallium phosphide diodes.

1.2 Solar cells

Gallium is used in the manufacture of solar cells, such as gallium arsenide IIIV solar cells, which have good heat resistance, radiation resistance and other characteristics, and their photoelectric conversion rate is very high.

1.3 Alloys

Gallium and indium, thallium, tin, bismuth, zinc, etc. can form a series of low-melting alloys between 3 degree and 65 degree , which are used for temperature measurement and control, mercury substitutes in instruments, supports in beading operations, and metal coatings. Cooling circuits for layers, electronics and nuclear industries. For example, a gallium alloy containing 25 percent indium is a low melting point alloy that melts at 16 degree and can be used in automatic fire extinguishing devices. Gallium and copper, nickel, tin, gold, etc. can form cold flux, which is suitable for difficult-to-weld special-shaped thin walls, cold welding between metals and between ceramics and cavity blocking.

1.4 Medical field

Gallium can be used in medical diagnostics, such as the use of gallium citrate (67Ga) to diagnose lung and liver cancer. Gallium alloys can also be applied to medical devices and medical materials, such as using gallium alloys as tooth filling materials, using "indium gallium alloys" to make thermometers, etc.