Silicon nitride, with the chemical formula Si3N4, is an inorganic compound that appears as a light off-white powder or solid. It can be synthesized through two main methods: heating high-purity silicon powder in a nitrogen atmosphere, or reacting silicon halides with ammonia gas under controlled conditions. A key characteristic of this material is its excellent chemical stability—it does not react with any inorganic acids except hydrofluoric acid, and it boasts strong corrosion resistance as well as high-temperature oxidation resistance, making it suitable for harsh working environments.
As an advanced high-tech material, silicon nitride has a wide range of derivatives and related products, including ferrosilicon nitride, ferrochrome nitride, and silicon manganese nitride, which are widely used in various industrial fields. In recent years, the silicon nitride industry has witnessed significant technological advancements and market growth, driven by increasing demand from emerging sectors such as new energy vehicles and semiconductor manufacturing.
Latest Silicon Nitride Industry News 2026
2026 has seen remarkable progress in the silicon nitride industry, with several key developments shaping its future. A new international patent related to silicon nitride ceramic substrates was published in early March 2026, focusing on improving the preparation process of silicon nitride green bodies and ceramic sheets. This technology is expected to enhance the thermal conductivity and reliability of silicon nitride substrates, which are core components for third-generation semiconductor power modules in high-voltage fast-charging vehicles.
According to industry research reports, the global silicon nitride market sales volume is expected to reach 0.91 billion US dollars in 2026, with a compound annual growth rate (CAGR) of 4.70% from 2026 to 2033. The market growth is mainly driven by the rising demand for silicon nitride in electric vehicles, aerospace, and semiconductor industries. Additionally, a new national standard for silicon nitride ceramic substrates was officially released in 2025, which will standardize product quality and promote the healthy development of the industry.
Another notable advancement is the development of a new Cf/Si3N4 composite material with ultra-high temperature resistance and anti-brittleness. This material, composed of carbon fiber reinforcement and silicon nitride matrix, is designed for use in aerospace high-temperature structural components, expanding the application scope of silicon nitride in extreme environments.
Physical and Chemical Indexes of Silicon Nitride
The chemical composition of silicon nitride (Si3N4) varies slightly according to its grade, and the following table shows the standard indexes for the common Si3N485-99 grade, which is widely used in industrial production. The table is designed to be compatible with WordPress basic format to avoid display errors.
| Grade | N (%) | Si (%) | Ca min (%) | O min (%) | C min (%) | Al min (%) | Fe min (%) |
| Si3N485-99 | 32-39 | 55-60 | 0.25 | 1.5 | 0.3 | 0.25 | 0.25 |
Features of Silicon Nitride Powder
Silicon nitride powder is a critical raw material for manufacturing silicon nitride ceramics, and its performance directly affects the molding, sintering, and final product quality of silicon nitride ceramics. High-quality silicon nitride powder has the following key features:
It exhibits excellent corrosion resistance, thermal shock resistance, and wear resistance, enabling it to operate stably at temperatures below 1900 degrees Celsius.
It has superior fracture toughness, stable chemical composition, and good thermal conductivity, which is essential for heat dissipation in high-temperature applications.
The powder contains high-purity nitrides, featuring low expansion rate, high thermal conductivity, and high strength, with almost no shrinkage during heating, ensuring dimensional stability of the final products.
It possesses high strength and wear resistance, making it suitable for producing high-performance components.
It has strong high-temperature oxidation resistance—after long-term use at high temperatures, an oxide film forms on the surface, protecting the internal material from chemical reactions and extending its service life.
Ceramic-grade silicon nitride powder, which is widely used in high-end applications, typically has high alpha-phase content, high purity (impurity content less than 200ppm), narrow particle size distribution, and high sintering activity. These characteristics make it ideal for manufacturing silicon nitride cutting tools, bearing balls, and other products requiring high sintering performance.
Applications of Silicon Nitride
Silicon nitride has a wide range of applications across multiple industries, thanks to its excellent comprehensive performance. It is widely used in steelmaking, metallurgy, machinery, chemical engineering, electronics, military, and nuclear industries, as well as in normal and high-temperature sealing abrasives such as wear-resistant rubber, plastics, and ceramics.
In the steelmaking industry, silicon nitride coatings effectively solve the problem of oxidation and burnout during billet heat treatment. Experimental data shows that nano-silicate anti-oxidation coatings containing silicon nitride can reduce the oxide scale of ordinary hot-rolled plates from 3%-5% to 0.1%-0.8%, and the oxide scale of stainless steel hot-rolled plates from 1%-3% to less than 0.2%. Additionally, silicon nitride is used as a key component in tap hole mud, which enhances sintering activation, corrosion resistance, and crack resistance, ensuring stable sealing of blast furnace mouths and easy breaking. It is also used as a nitrogen enhancer in the production of HRB400 hot-rolled steel bars, forming a new alloying process that improves the performance and stability of the steel bars. Compared with boron nitride, silicon nitride has the second-highest nitrogen content per unit mass and a lower price, making it a cost-effective nitrogen-increasing material.
In the metallurgical industry, silicon nitride is used as a high-performance refractory material for high-temperature engineering components. Due to its high-temperature resistance, low friction coefficient, self-lubricating property, and stability in most metal alloy solutions, it is widely used to manufacture tools and molds for metal processing, such as core rods, extrusion and wire drawing molds, rolls, conveyor rollers, heating element fixtures, thermocouple sleeves, metal heat treatment supports, crucibles, aluminum liquid guides, and aluminum ladle linings. When combined with SiC, it forms Si3N4-SiC refractory materials used in blast furnace shafts and other parts. When mixed with BN, Si3N4-BN materials are used to make horizontal continuous casting separation rings, which have uniform structure, high mechanical strength, good thermal shock resistance, and are not wetted by molten steel, meeting the process requirements of continuous casting.
In the mechanical industry, silicon nitride ceramics are used to produce bearing balls, rollers, ball seats, molds, new ceramic cutting tools, pump plungers, and spindle sealing materials. In the chemical industry, they are used as wear-resistant and corrosion-resistant components such as ball valves, pump bodies, combustion vaporizers, and filters. With the development of the electronics and semiconductor industries, silicon nitride ceramic materials are also increasingly used in electronic components, military equipment, and nuclear industry components.
Production Process of Silicon Nitride
Silicon nitride products can be classified into reaction-sintered products, hot-pressed products, atmospheric sintered products, isostatic pressure sintered products, and reactive re-fired products according to their fabrication processes. Among these, reaction sintering is the most commonly used method for producing silicon nitride refractory products due to its simplicity and cost-effectiveness.
The reaction sintering process involves the following steps: first, finely ground silicon powder (with a particle size generally less than 80μm) is formed by machine pressing or isostatic pressing. After the green body is dried, it is heated to 1350～1400℃ in a nitrogen atmosphere, and nitridation occurs simultaneously during the sintering process to form silicon nitride. The performance of the final product is greatly influenced by raw material conditions, calcination process, and atmosphere conditions.
Silicon powder usually contains impurities such as Fe, Ca, Al, and Ti. Fe acts as a catalyst in the reaction process, promoting the diffusion of silicon, but it can also cause defects such as pores. The main functions of Fe as an additive are: promoting the formation of an SiO2 oxide film on the product surface; forming an iron-silicon melt system, where nitrogen dissolves in liquid FeSi2 to promote the formation of β-Si3N4. However, excessive Fe content or overly large Fe particles can lead to pores and other defects, reducing product performance. Generally, the addition amount of Fe is 0-5%. Impurities such as Al, Ca, and Ti can easily form eutectics with silicon, and appropriate addition can promote sintering and improve product performance.
The particle size of silicon powder also affects the sintering process: the finer the particle size and the larger the specific surface area, the lower the sintering temperature required. Compared with coarse-grained silicon powder, fine-grained silicon powder produces products with higher α-Si3N4 content, smaller microscopic pores, and higher density when the particle size ratio is appropriate.
Temperature has a significant impact on the nitridation rate. The nitridation reaction starts at 970-1000℃, and the reaction rate accelerates around 1250℃. In the high-temperature stage, if the temperature exceeds the melting point of silicon (1420℃) too quickly, the exothermic reaction will cause silicon to flow, leading to melting and collapse of the silicon powder body. Therefore, strict temperature control is crucial during the sintering process.