Preparation and main application of magnesium silicide

Overview of magnesium silicide Mg2Si powder

Magnesium silicide ,an inorganic compound, has a chemical formula of Mg₂Si and a molecular weight of 76.71. Cyan or light purple powder, cubic crystal. The melting point is 1102°C and the relative density is 1.94.

Magnesium silicide is insoluble in cold water and decomposes in hot water. It can be completely decomposed in vacuum, or heated to 1200°C under hydrogen flow. Stable to alkaline solutions. Decomposes to produce silane and hydrogen. Mg2Si is the only stable compound in the MG-Si binary system. It has the characteristics of high melting point, high hardness, and high elastic modulus. It is a narrow band gap n-type semiconductor material that can be used in optoelectronic devices, energy devices, lasers, semiconductors and heavy metals. Fields such as temperature control communication have important application prospects. In the Mg2Si phase, the crystal has an overall structure, belonging to a face cubic lattice, the space group is FM3M, the group number is 225, and the lattice constant a=0.6391nm. In the crystal structure, each Si atom is located at the (0, 0, 0) position, forming a face cubic structure with side length A. The MG atom is located at each position (0.25, 0.25, 0.25). The MG atom is located in the center of the tetrahedron composed of Si atoms. Magnesium silicide is a narrow band gap semiconductor. The growth of the crystal exhibits n-type conductivity, but it can be doped by doping Ag, Ga, Sn and possibly Li (high doping level).

As the focus of solar energy development and utilization, the polysilicon industry has shown rapid development and expansion in my country in recent years, effectively promoting the development of my country's new energy industry. The photovoltaic industry centered on solar power technology has developed rapidly. At present, the main reason for the rapid development of solar power generation technology is still the production cost of polysilicon, the main material for preparing solar power equipment, which accounts for about 50% of the total cost of solar power generation. Exploring low-cost, high-quality polysilicon production methods is one of the effective ways to promote the rapid development of the photovoltaic industry. As the high-purity polysilicon market is severely in short supply, many downstream companies in the photovoltaic solar industry are suffering from the shortage of polysilicon. In terms of the technology for producing high-purity polysilicon, a variety of production process routes coexist at present. The main traditional processes for polysilicon production in the world are the modified Siemens method and the silane thermal decomposition method. Among them, the silane thermal decomposition method is a low-energy, high-yield method that has developed rapidly in recent years. Silane, as an indispensable special gas for the production of polysilicon and energy-saving glass, is widely used in electronic products, high-efficiency solar cells, aerospace and military industries. At present, the methods for producing silane in the world mainly include the Japanese Komatsu electronic method (magnesium silicide method), the lithium hydride reduction method of trichlorosilane, the American MEMC company’s proprietary sodium aluminum hydride reduction method of silicon tetrafluoride and the UCC method (chlorosilane method). Hydrogenation and secondary disproportionation reactions). Magnesium silicide method has the advantages of low investment, mature technology and low energy consumption. As an important raw material for the production of silane by magnesium silicide method, the existing research mainly focuses on the research of magnesium silicide preparation equipment, and there is little research on the preparation process of magnesium silicide. 

Preparation of Magnesium Silicide Mg2Si Powder

Method 1: Mix 100g of silicon powder and magnesium powder with a particle size of 180 mesh in a certain molar ratio, mix them into an iron boat, put it into a tubular reactor, evacuate and replace the reaction system with hydrogen for 3 times, then evacuate to 133Pa,

The reactor is closed, the temperature is slowly raised to a certain temperature, and after the reaction is kept for a period of time, the temperature is lowered to room temperature at a certain rate, and the reaction product is taken out, and samples are taken for XRD analysis after grinding. Through the research on the preparation process of magnesium silicide, the optimized process conditions are: reaction temperature 600℃, reaction time 4h, molar ratio of Mg:Si 2.02:1, cooling rate 10℃/min, product quality is stable, and magnesium silicide content is greater than 98%.

Method 2: A method for preparing magnesium silicide powder, according to the following process steps:

(1). Fully stir magnesium powder and silicon powder with a mass ratio of 1.6-2. The particle size of the magnesium powder is 50-200 mesh, and the particle size of the silicon powder is 50-200 mesh. The ball milling is carried out under the protection of% argon, and the ball milling time is 0.5 to 2 hours;

(2) Put the ball-milled powder into a quartz crucible, and heat it in a tube furnace under the protection of 99.99% argon. The heat treatment time is 0.5 to 2 hours. The reaction temperature in the tube furnace The temperature is 450～600oC, and the product is taken out after the reaction is cooled to below 80oC;

(3) Put the obtained product into a ball milling tank, continue ball milling under the protection of 99.99% argon gas, the ball milling time is 0.1 to 5 hours, and the particle size of the powder is 1 to 5 microns to obtain the final product.

Magnesium silicide Mg2Si powder application

Magnesium silicide is mainly used to synthesize other silicides. Examples of its applications are as follows:

1) Synthesize MgSiN2 powder. It belongs to the field of preparation of non-oxide ceramic powder. It is prepared by reacting magnesium silicide or a mixture of magnesium silicide and α-Si3N4 as starting materials in 1-10MPa nitrogen or a mixture of nitrogen and hydrogen (95-98%: 5-2%). During the production process, there is no need for pre-compacting, and the reaction is carried out in an upright annular cylinder or disc-shaped container made of carbon felt. The invention adopts a combustion synthesis process. Compared with literature reports, it not only has the advantages of no environmental pollution, low energy consumption, and suitability for industrial large-scale production, but also has high purity of the synthesized product, and the oxygen content can be controlled to <0.5%, which is suitable for preparation High-strength, high thermal conductivity silicon nitride and aluminum nitride ceramic substrate materials and additives for microelectronic packaging materials, etc.

2) The use of by-products in the preparation of silane by the magnesium silicide method. Because the by-product has a high ammonia storage density; because the hydrogen content of ammonia is as high as 17.6wt% and combined with low-temperature catalytic ammonia decomposition to produce hydrogen, the solid metal ammonia complex with high ammonia content becomes a new type of hydrogen storage material. Used in the field of fuel cells. Compared with the method of preparing metal ammonia complex by reaction of alkaline earth metal halide and ammonia gas adopted by scholars at home and abroad, the process of preparing Mg(NH3)6Cl2 by magnesium silicide method is simple and has been produced. In the process, the comprehensive utilization of solid waste, environmental protection and energy conservation are all of great significance.

Magnesium silicide Mg2Si powder price

The price product factors of magnesium silicide Mg2Si powder, such as production cost, transportation cost, international situation, exchange rate, supply and demand, vary randomly. Tanki New Materials Co., Ltd. aims to help various industries and chemical wholesalers find high-quality, low-cost nanomaterials and chemicals by providing a full set of customized services. If you are looking for magnesium silicide Mg2Si powder product materials, please feel free to contact us for the latest price of magnesium silicide Mg2Si powder.

Magnesium silicide Mg2Si powder supplier

As a global magnesium silicide MgSi2 powder supplier, Tanki New Materials Co., Ltd. has extensive experience in the performance, application and cost-effective manufacturing of advanced and engineered materials. The company has successfully developed a series of powder materials (molybdenum disilicide, titanium silicide, calcium silicide, iron boride), high-purity targets, functional ceramics and structural devices, and provides OEM services.