Application of molybdenum and its alloys
With the development of science and technology, the application of molybdenum in high technology and other fields is also increasing. Next, let's learn about the application of molybdenum and its alloys.
1. Steel industry
According to the world molybdenum consumption statistics, the application of molybdenum in iron and steel industry still occupies the most important position. As an alloying element of steel, molybdenum can improve the strength of steel, especially the high temperature strength and toughness; improve the corrosion resistance of steel in acid-base solution and liquid metal; improve the wear resistance of steel and improve the hardenability, weldability and heat resistance. Molybdenum is a good carbide forming element, which will not be oxidized in the process of steelmaking. It can be used alone or together with other alloy elements.
Molybdenum can be used together with chromium, nickel, manganese and silicon to produce different types of stainless steel, tool steel, high speed steel and alloy steel. The stainless steel has good corrosion resistance, which can be used for corrosion-resistant steel pipe, automobile shell, sewage treatment equipment, etc. A kind of stainless steel with 6% molybdenum can also replace titanium in seawater desalination plant, ocean going ship, offshore oil and gas production pipeline.
Molybdenum series high speed steel has the advantages of carbide inhomogeneity, wear resistance, good toughness and high temperature plasticity, which is suitable for manufacturing forming tools. Molybdenum alloy steel can be used to manufacture machine tool structural parts, industrial vehicles and bulldozing equipment.
2. Agricultural fertilizer
Molybdenum is one of the essential "trace elements" in plants, which can significantly improve the quality and yield of legumes, forages and other crops. Therefore, ammonium molybdate is often contained in fertilizers. Molybdenum can promote the fixation of nitrogen in the air by rhizobia and other nitrogen fixing organisms, and further transform nitrogen into protein needed by plants; molybdenum can promote the absorption of phosphorus by plants and play its role in plants; molybdenum can accelerate the formation and transformation of carbohydrate in plants, improve the content and stability of chlorophyll, and increase the content of vitamin C. Moreover, molybdenum can improve the drought resistance, cold resistance and disease resistance of plants.
The application of molybdenum fertilizer is characterized by small amount, high yield and low cost. It is an important measure to improve the agricultural harvest, especially the soybean harvest.
3. Electronic and electrical
Molybdenum has good conductivity and high temperature performance, especially the thermal expansion coefficient of glass is very close, so it is widely used in the core wire, lead wire, side bar and other parts of the spiral filament in the bulb, as grid and anode support material in the electron tube.
In VLSI, molybdenum is used as the metal oxide semiconductor gate, and the bimetallic effect can be eliminated by mounting the integrated circuit on molybdenum. The ultra-thin seamless molybdenum tube (about 15 μm) can be used as the anode support of the picture tube of high-definition TV. The number of image scanning lines of this kind of TV is 1125, which is 2 times higher than that of ordinary TV. The molybdenum wafer can also be used as the heat insulation of power transistor Base plate and heat sink of screen and silicon rectifier. In modern electronic industry, in addition to pure molybdenum, Mo-Re alloy can be used as structural materials for electron tubes and special light bulbs, and Mo-50Re and TZM alloy can also be used as thermionic cathode structural components in high-power microwave tubes and millimeter wave tubes.
4. Automobile spraying
The melting point of molybdenum is as high as 2620 ℃, and it has good high temperature performance and corrosion resistance, and has strong binding force with steel, so it is the main thermal spraying material in the production of automobile parts. Thermal spraying materials can significantly improve the performance of piston ring, synchronous ring, fork and other worn parts, and can also be used to repair worn crankshaft, roll, shaft rod and other mechanical parts.
5. High temperature components
Due to its high purity, high temperature resistance and low steam pressure, molybdenum is often used to make heating elements and structural materials for high temperature furnaces. Molybdenum has good ablation resistance in fused quartz. It is commonly used as electrode for electrified melting in glass industry, and its service life can reach more than one year. In addition to being used as electrode, molybdenum can also be used as high temperature structural material for glass melting, such as guide groove, tube, etc. Using molybdenum instead of platinum in glass fiber drawing furnace has a good effect and greatly reduces the production cost. In addition, molybdenum and its alloys can also be used as hot isostatic pressing furnace frame, heat shield, sintering and steaming paint boat, etc.
Molybdenum silicide is a widely used material for electric heating components. It has the characteristics of high temperature oxidation resistance, excellent corrosion resistance and high melting point, and has a long service life.
6. Oil exploitation
Molybdenum can not only be used in oil and gas field drilling pipeline, but also often combined with cobalt and nickel as catalyst for petroleum refining pretreatment, mainly for desulfurization of petroleum, petrochemical products and liquefied coal. In the process of hydrogen treatment. Sulfide will react with hydrogen on the surface of the catalyst, so that sulfur ions will be released in the form of hydrogen sulfide. At the same time, nitrogen and metal impurities in crude oil will be eliminated, so as to reduce the poisoning of these impurities on other catalysts during oil refining, so as to improve the color, smell and stability of the product. After passivation, a layer of carbon remains on the surface of Mo based catalyst. If the carbon layer is burned off, the catalyst can recover its activity, and its life can be 1-5 years. Molybdenum plays an important role in petroleum cracking and reforming. It is an ideal electron donor and carrier.
In addition to the above applications, molybdenum and its alloys can also be used in nuclear industry, aerospace and environmental protection.