How is silicon nitride Si3N4 powder produced?

Overview of Silicon Nitride Si3N4 Powder

Silicon nitride is a compound of silicon and nitrogen. Silicon nitride is an inorganic substance with the chemical formula Si3N4. It is an important structural ceramic material with high hardness, inherent lubricity, and wear resistance. It is an atomic crystal; it is resistant to oxidation at high temperatures. Moreover, it can resist the impact of cold and heat. It will not be broken if it is heated to above 1000°C in the air, cooled rapidly and then heated rapidly. It is precisely because of the excellent characteristics of silicon nitride ceramic that people often use it to manufacture mechanical components such as bearings, turbine blades, mechanical seal rings, permanent molds, and so on. If silicon nitride ceramics, which are resistant to high temperatures and difficult to transfer heat, are used to make the heating surfaces of engine components, not only can the quality of the diesel engine be improved, fuel savings, and thermal efficiency can be improved. 

Characteristics of Silicon Nitride Si3N4 Powder

Silicon nitride ceramics have high fracture toughness and strength at room temperature. Even at high temperatures, their strength will not drop too much, and high temperature stability is good. It has the following characteristics:

(1) Silicon nitride material has low linear expansion coefficient, good thermal conductivity and excellent thermal shock resistance;

(2) The hardness of silicon nitride is very large, 99.5, second only to a few superhard materials such as diamond and BN;

(3) Silicon nitride has a small friction coefficient, self-lubricating and abrasion resistance;

(4) Silicon nitride has good mechanical properties, hot pressing and reaction sintering samples can obtain high bending strength, even up to Giga Pa. Its high temperature stability is good, and it still has high bending strength at high temperature, and high temperature creep is small;

(5) Silicon nitride material has good insulating properties and is a good insulating material at high temperatures;

(6) The chemical properties of silicon nitride are very stable, and it is not corroded by all inorganic acids except hydrofluoric acid. It can also exist stably in some alkalis;

(7) When silicon nitride ceramics are oxidized, a dense silicon dioxide film is easily formed on the surface to prevent continued oxidation. Its anti-oxidation temperature can reach 1400℃, and it can reach 1870℃ when used in a reducing atmosphere.

(8) Silicon nitride is non-wetting to high-temperature metal solution and molten slag, and can be used as a high-temperature metal solution filter and an excellent corrosion-resistant material for molten slag.

Silicon nitride is considered by the material industry as an engineering ceramic material with excellent comprehensive performance, which can be used in high temperature fields.

Although the properties of silicon nitride have long been well known, the silicon nitride (approximately 2×5µm in size) that exists in the natural world of the earth was only discovered in meteorites in the 1990s. To commemorate the pioneer of mass spectrometry research, Alfred Otto Carl Neal named this type of silicon nitride ore found in nature "nierite". However, there is evidence that this type of silicon nitride ore in meteorites may have been found in Azerbaijan in the former Soviet Union earlier. Meteorites containing silicon nitride minerals have also been found in Guizhou Province, China. In addition to meteorites on Earth, silicon nitride is also distributed in cosmic dust in outer space.

How is silicon nitride Si3N4 powder produced?

Hexagonal β-Si3N4 can be directly processed to silicon nitride, and nitrogen can be processed at 100-1400°C.

SiCL4(L)+6NH3(g)→Si(NH)2(S)+4NH4Cl(S) 0℃ under conditions

3Si(NH)2(S)→Si3N4(S)+N2(g)+3H2(g) under 1000℃

Or use carbothermal reduction reaction under nitrogen atmosphere at 1400-1450°C under nitrogen atmosphere: 3SiO2(S)+ 6C

(S)+2N2(g)→Si3N4(S)+6CO(g)

However, if the silicon raw material used is of high purity, it will cause silicon nitride to produce silicate and iron containing impurities. The silicon nitride synthesized by the decomposition of diamine is amorphous and needs to be further annealed at 1400-1500°C in nitrogen before it can be converted into crystalline powder. The decomposition of diamine is only important. Commercially, silicon nitride is produced by a nitridation method. Carbothermal reduction reaction is the simplest method to produce silicon nitride, and it is also the most economical method to produce silicon powder in industry.

Electronic grade silicon nitride film is made by chemical vapor deposition or plasma enhanced chemical vapor deposition technology:

3 SiH4 (G) + 4 NH3 (g) → Si3N4 (S) + 12 H2 (g)

3 SiCL4 (G) + 4 NH3 (g) → Si3N4 (S) + 12 HCl (g)

3 SiCL2H2 (G) + 4 NH3 (g) → Si3N4 (S) + 6 HCl (g) + 6 H2 (g)

If you want to deposit silicon nitride on a semiconductor substrate, there are two methods available:

Vertical or horizontal tube furnaces use low-pressure chemical vapor deposition technology at relatively high temperatures.

Plasma-enhanced chemical vapor deposition technology is carried out at a relatively low temperature under vacuum conditions.

The battery parameters of silicon nitride are different from that of single textile silicon. Therefore, depending on the deposition method, the generated silicon nitride film may generate tension or stress. In particular, when plasma-enhanced chemical vapor deposition technology is used, the tension can be reduced by adjusting the deposition parameters.

The soluble gel is used to prepare silica, and then the silicon nanowires are treated with silica gel to process the carbothermic reduction method and nitride. The special carbon particles in silica gel are produced by glucose at 1200 to 1350 °C.

Application of silicon nitride Si3N4 powder

Manufacturing structure: such as metallurgy, machinery, aviation, aerospace.

Surface treatment of metals and other materials: such as molds, knives, turbine blades.

Composite materials: such as metal, ceramic and graphite composite materials, rubber, plastics

Colorless transparent self-lubricating wear-resistant nanoparticle film for mobile phones;

Advanced surface protection, such as automobiles;

jack;

Ball valves and parts;

Corrosion resistant turbine;

Manufacturing ball/roller bearings, bushings, valves and other wear parts in metallurgy, aviation, chemical, energy, machinery and other industries;

Manufacturing cutting tools, molds, cylindrical wall coatings, turbine rotors and blades;

Manufacturing ceramics, graphite, rubber, metal, adhesives and other composite materials.

Nozzles, rockets and missile nozzles.

Silicon nitride Si3N4 powder price

The price of silicon nitride Si3N4 powder will vary randomly with changes in production costs, transportation costs, international situations, exchange rates and the supply and demand of silicon nitride Si3N4 powder. 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 silicon nitride Si3N4 powder, please feel free to send an inquiry to get the latest price of silicon nitride Si3N4 powder.

Silicon Nitride Si3N4 Powder Supplier

As a global silicon nitride Si3N4 powder supplier, Tanki New Materials Co.,Ltd. has extensive experience in the performance, application and cost-effective manufacturing of advanced engineering materials. The company has successfully developed a series of powder materials (titanium nitride, silicon nitride, titanium nitride, etc.) high-purity targets, functional ceramics and structural devices, and provides OEM services.

Chemical Composition of Silicon Nitride Si3N4 Powder