Characteristics and preparation of silicon nitride

Silicon nitride synthesis method

Hexagonal β-Si3N4

Silicon nitride can be directly combined with elemental silicon and nitrogen under the condition of 1300-1400℃:

3 Si(s) + 2 N2(g) → Si3N4(s)

Can also be synthesized with diimine

SiCl4(l) + 6 NH3(g) → Si(NH)2(s) + 4 NH4Cl(s) at 0 ℃

3 Si(NH)2(s) → Si3N4(s) + N2(g) + 3 H2(g) at 1000 ℃

Or use carbothermal reduction reaction to synthesize under a nitrogen atmosphere at 1400-1450°C:

3 SiO2(s) + 6 C(s) + 2 N2(g) → Si3N4(s) + 6 CO(g)

The synthetic method of nitriding elemental silicon powder was developed in the 1950s with the rediscovery of silicon nitride. It is also the first method for mass production of silicon nitride powder. However, if the purity of the silicon raw material used is low, the produced silicon nitride will contain impurity silicate and iron. The silicon nitride synthesized by the diamine decomposition method is amorphous, and it needs to be further annealed under nitrogen at 1400-1500℃ to convert it into a crystalline powder. The diamine decomposition method is second only to the importance of Nitriding is a commercial production method of silicon nitride. Carbothermal reduction reaction is the easiest way to manufacture silicon nitride and it is also the most cost-effective way to manufacture silicon nitride powder in industry.

Electronic grade silicon nitride film is manufactured 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:

Use low-pressure chemical vapor deposition technology at relatively high temperatures using vertical or horizontal tube furnaces.

The plasma-enhanced chemical vapor deposition technology is carried out under relatively low temperature vacuum conditions.

The unit cell parameters of silicon nitride are different from that of elemental silicon. Therefore, depending on the deposition method, the generated silicon nitride film may generate tension or stress. Especially when using plasma-enhanced chemical vapor deposition technology, the tension can be reduced by adjusting the deposition parameters.

Firstly, silica is prepared by the sol-gel method, and then the silica gel containing ultra-fine carbon particles is processed by the carbothermal reduction method and nitridation at the same time to obtain silicon nitride nanowires. The ultrafine carbon particles in silica gel are produced by the decomposition of glucose at 1200-1350°C. The reactions involved in the synthesis process may be:

SiO2(s) + C(s) → SiO(g) + CO(g)

3 SiO(g) + 2 N2(g) + 3 CO(g) → Si3N4(s) + 3 CO2(g) or

3 SiO(g) + 2 N2(g) + 3 C(s) → Si3N4(s) + 3 CO(g)

Features of Silicon Nitride

Except for hydrofluoric acid and hot phosphoric acid, it does not react with other inorganic acids and has strong corrosion resistance

Overview of silicon nitride Si3N4 powder

Silicon nitride Si3N4 powder is an inorganic substance with a chemical formula of Si3N4. It is an important structural ceramic material with high hardness, inherent lubricity, wear resistance, atomic crystallinity and high temperature oxidation resistance.

Application of silicon nitride Si3N4 powder

The main uses of silicon nitride Si3N4 powder are as follows

1) Manufacturing structural equipment: metallurgy, machinery, aviation, aerospace, etc.

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

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

4) Colorless, transparent, self-lubricating, wear-resistant nano-particle film, used for high-level surface protection such as mobile phones and automobiles.

5) Ball bearings.

6) Ball valves and parts.

7) Corrosion resistant turbine.

Other applications of silicon nitride Si3N4 powder

Silicon nitride Si3N4 powder is used as high-grade refractory material. For example, SI3N4-SIC refractory materials and sic are used in blast furnace bodies and other parts, and SI3N4-BN materials and BN are used in horizontal continuous casting separation rings. Continuous casting separation ring is a fine structure ceramic material with uniform structure, high mechanical strength, good thermal shock resistance, and will not be wetted by molten steel, which meets the requirements of continuous casting process

Silicon nitride Si3N4 powder ceramic material has excellent properties such as high thermal stability, strong oxidation resistance, and high product dimensional accuracy. Since silicon nitride is a covalent compound with high bonding strength, it can form an oxide protective film in the air, so it also has good chemical stability and will not be oxidized below 1200°C. The protective film formed at 1200~1600°C can prevent further oxidation and will not be penetrated by many molten metals or alloys such as aluminum, lead, tin, silver, brass, and nickel. Or corrosion, but it can be corroded by molten magnesium, nickel-chromium alloys, stainless steel and other melts.

Silicon nitride Si3N4 powder ceramic materials can be used for high-temperature engineering parts, advanced refractories in the metallurgical industry, corrosion-resistant parts and seals in the chemical industry, tools and knives in the machining industry, etc. It can form a strong bond with silicon carbide, aluminum oxide, thorium dioxide, boron nitride, etc., so it can be used as a bonding material to be modified in different proportions.

In addition, silicon nitride can also be applied to solar cells. After the silicon nitride film is coated by the PECVD method, it can not only be used as an anti-reflection film to reduce the reflection of incident light, but also in the deposition process of the silicon nitride film, the hydrogen atoms of the reaction product enter the silicon nitride film and the silicon wafer passivation Defects. The ratio of the number of silicon nitride to silicon atoms here is not strictly 4:3, but depends on the process conditions within a certain range. Internal fluctuations, different atomic ratios correspond to different physical properties of the film.

Used in ultra-high temperature gas turbines, aircraft engines, electric furnaces, etc.

Silicon nitride Si3N4 powder price

The price of silicon nitride Si3N4 powder will change randomly according to factors such as production cost, transportation cost, international situation, exchange rate, and supply and demand of silicon nitride Si3N4 powder market. 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.

Specification of Silicon Nitride Si3N4 Powder:
Product Name:Silicon Nitride
Purity:99%
Particle Size:0.5um-1um (α phase)

Chemical Composition of Silicon Nitride Si3N4 Powder: