Performance characteristics and applications of silicon nitride materials

What is silicon nitride?

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; Antioxidant at high temperatures. And it can also resist cold and hot shocks. When heated to over 1000 ℃ in the air, it will not shatter even after rapid cooling and heating. It is precisely because silicon nitride ceramics have such excellent properties that people often use them to manufacture mechanical components such as bearings, turbine blades, mechanical sealing rings, permanent molds, etc. If high-temperature resistant and heat-resistant silicon nitride ceramics are used to manufacture the heating surface of engine components, it can not only improve the quality of diesel engines, save fuel, but also improve thermal efficiency. China, as well as countries such as the United States and Japan, have developed this type of diesel engine.

Overview of Silicon Nitride

Silicon nitride (Si3N4) contains three crystal forms and two common crystal forms.

One type is α- Si3N4, needle shaped crystal, white or grayish white; Another type is β- Si3N4 is a dark dense granular polyhedron or short prism.

Due to the long stacking sequence, α The hardness of the phase is higher than β Xiang.

However, compared to β Compared to others, α The chemical properties of the phase are unstable.

Therefore, at high temperatures in the liquid phase, it is always caused by α Transforming into β Xiang. Therefore, β- Si3N4 is the main form used in silicon nitride ceramics.

Application of silicon nitride

Silicon nitride is used as advanced refractory material, such as when combined with sic to form SI3N4-SIC refractory material for blast furnace shafts and other parts; If cooperating with BN, SI3N4 BN material will be used for horizontal continuous casting separation rings. The SI3N4-BN series horizontal continuous casting separation ring is a fine structured ceramic material with a uniform structure and high mechanical strength. Good heat resistance and impact resistance, without being wetted by molten steel, meeting the requirements of continuous casting technology. Silicon nitride ceramic materials have excellent properties such as high thermal stability, strong oxidation resistance, and high product dimensional accuracy. Due to its high bond strength, silicon nitride is a covalent compound that can form an oxide protective film in air. Therefore, it also has good chemical stability. It is not oxidized below 1200 ℃, and the formation of a protective film at 1200-1600 ℃ can prevent further oxidation. It is not wetted or corroded by many molten metals or alloys such as aluminum, lead, tin, silver, brass, nickel, but can be corroded by molten solutions such as magnesium, nickel chromium alloys, and stainless steel.

Silicon nitride ceramic materials can be used for components in high-temperature engineering, advanced refractory materials in metallurgical industry, corrosion-resistant and sealing components in chemical industry, and cutting tools and tools in mechanical processing industry.

Due to the strong bonding between silicon nitride and silicon carbide, aluminum oxide, thorium dioxide, boron nitride, etc., it can be used as a bonding material for modification in different ratios.

In addition, silicon nitride can also be applied to solar cells. After depositing silicon nitride film using PECVD method, not only can it serve as an anti reflection film to reduce the reflection of incident light, but also during the deposition process of silicon nitride film, the reaction product hydrogen atoms enter the silicon nitride film and silicon wafer, playing a role in passivating defects. The ratio of silicon nitride to silicon nitride atoms here is not strictly 4:3, but fluctuates within a certain range depending on the process conditions. Different atomic ratios correspond to different physical properties of the thin film.

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

Characteristics of silicon nitride

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

Silicon nitride price

The price of silicon nitride ceramics varies randomly with production costs, transportation costs, international situation, exchange rates, and the supply and demand relationship in the silicon nitride market. Tanki New Materials Co. Ltd aims to assist all industries and chemical wholesalers in finding high-quality, low-cost nanomaterials and chemicals by providing a full range of customized services. If you are looking for silicon carbide materials, please feel free to contact us for the latest prices of silicon carbide.

Silicon nitride supplier

As a global supplier of silicon nitride, 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 range of powder materials (including oxides, carbides, nitrides, single metals, etc.), high-purity targets, functional ceramics, and structural devices, and provided OEM services.

Chemical Composition of Silicon Nitride Si3N4 Powder: