What is the function of silver _ What is the function of silver?

The demand for silver is based on three pillars: industry, photography and silverware. These three categories account for more than 90% of the total consumption of silver.

1, for industrial use.

In the electronic industry, the biggest use of silver is thick film paste, which is usually used to make screen printed circuits in multilayer ceramic capacitors, thin film switches, heating films for automobile rear windshields and conductive adhesives.

Silver has a unique light reflectivity, and the reflectivity after polishing reaches 100%, which can be used on mirrors, glass, cellophane or metal.

Many batteries, rechargeable batteries and disposable batteries use silver alloy as cathode. Although expensive, the energy of silver-containing batteries is better than other types of batteries. The most common is the button-sized silver oxide battery (containing 35% silver), which is usually used in watches, cameras and similar electronic products.

A large number of chemical reactions use reticulated and crystalline silver as catalysts. For example, silver is used as a catalyst for formaldehyde in plastic production and for ethylene oxidation in petrochemical industry.

The flexibility and strength of silver promote the connection of materials (above 600℃ is called brazing, hereinafter referred to as soft welding). Silver brazing alloy has a wide range of applications, from power equipment such as air conditioners and refrigerators to automobile, aerospace and aviation industries.

Compared with other bearings, bearings plated with pure silver have higher fatigue strength and bearing capacity, so they are used in various high-tech and heavy-load occasions.

2. photography.

The photographic process is based on the photosensitivity of silver halide crystal, which consists of soluble silver solution, usually silver nitrate containing soluble alkali metal halide (such as sodium chloride or potassium bromide), and these particles are suspended in unexposed film. The effect of light on silver halide destroyed the structure of this mixture. Under certain conditions, this mixture was reduced to metallic silver by the developer, and the image on the negative was converted into positive. Photographic film is used for X-ray photography, printing and commercial photography. Manufacturers of photographic films need high-purity silver.

3. Silver ornaments and silverware. The machinability of silver is similar to that of gold, both of which have good reflectivity and can reach high brightness after polishing. Pure silver (99.9%) does not lose its luster easily. In order to make jewelry have lasting luster, a small amount of copper is usually mixed into it. Silver is also used in gold alloys with base metals. Since14th century, the standard pure silver with purity of 92.5% has been the standard for making silverware, especially for making "containers" and flat tableware (knives, forks, spoons, etc. ). The coating of electroplated silverware is usually 20 ~ 30 microns thick, and the gold-plated jewelry is only 3 ~ 5 microns.

4. Silver coins.

Compared with gold, silver is more used to make money and enter the circulation field because of its large supply and low value. Most countries have established the silver standard, and silver coins did not become the main currency in circulation until the end of 19. But after the intervention of gold, the silver standard gradually gave way to gold. Silver gradually withdrew from the mint industry, but it still exists in some coins in circulation.

New development of silver

It is very important to evaluate the source of future demand for silver in the past few years. After analyzing and judging more investigations, many potential applications will move from the laboratory to the market. In the past few years, the most noteworthy area of silver is biocide. The application of silver in current-carrying superconductors has also made great progress.

The bactericidal effect of silver has long been recorded. But until recently, the progress of research and production technology of nanoparticles promoted the wide application of silver as a bactericide. At present, new products containing silver have been successfully commercialized, and silver has been successfully applied as a part of artificial goods to achieve the purpose of sterilization with a very small amount.

For example, now the washing machine can release silver particles when washing clothes. The silver ions released by the bandage can shorten the treatment time and reduce the frequency of replacement. The three largest manufacturers of wound products have adopted this technology, which has expanded their development space. Sportswear can regulate body temperature by adding silver ions, and can also reduce body odor.

Similarly, the application of silver surface disinfectant has made a breakthrough, and it has been widely used in food processing plants, disinfection centers and household items.

The application of silver in fungicides is still developing. Cost plays an important role here. On the one hand, people hope to replace silver with other cheap metals, but they are worried that the environment will be destroyed. Biocide manufacturers are constantly applying their products to new fields. The most potential field comes from the construction industry, and pesticides can prevent molds and other bacteria from damaging buildings. The most important building material to be treated is wood. A large number of studies have shown that silver pesticides have a significant destructive effect on woody fungi, insects and other organic organisms.

Another application of silver is in the field of high temperature superconducting wires. High temperature superconducting wires with ceramic core and silver sheath have been developed for new power plants and distribution networks. After the development of the second generation superconducting wire, the conductivity has been improved, the efficiency is higher and the application prospect is broader. Although the second generation uses less silver per meter compared with the first generation superconducting wire rod, the expansion of application scope will also drive the increase of silver consumption.