Silicon nitride ceramics have three crystal structures of α, β and γ, among which the α and β phases are the most common forms of silicon nitride. Because of their excellent resistance to wear, corrosion, high temperature, oxidation, thermal shock, as well as low specific gravity, silicon nitride materials are regarded as the most promising materials in high-temperature structural ceramics.
Advantages of Silicon Nitride Tube
Extremely High Hardness
Silicon nitride ceramic is a superhard material with a hardness of up to HRA91-93. Its mechanical characteristics are superior to those of oxide ceramics, and has better compressive strength and impact resistance.
Excellent Thermal Properties
Silicon nitride tubes have excellent thermohardness and can withstand high temperatures of up to 1300-1400°C. But if the temperature exceeds 1200°C, they will appear breakage as the usage time rises, and their strength will reduce as well. Consequently, the long-term service temperatures of silicon nitride tubes are typically not above 1200 °C. In addition, when compared to oxide ceramic tubes like alumina and zirconia, the hot-pressed and sintered silicon nitride tube offers greater thermal shock resistance. When heated to 1000°C and placed in cold water, it will not break, making it appropriate for rapid cooling and rapid heating situations under high temperatures.
Corrosion and Oxidation Resistance
With the exception of hydrofluoric acid, silicon nitride ceramics do not react with other inorganic acids. They have great corrosion resistance and high temperature oxidation resistance.
Self-Lubricating
Silicon nitride ceramics are naturally self-lubricating and can be utilized without lubricants.
Small High-Temperature Creep
Silicon nitride tubes exhibit small high-temperature creep, and produce very little slow plastic deformation when subjected to high temperatures and constant loads.
Low Coefficient of Friction
Because silicon nitride tubes undergo less chemical reaction with carbon, they have a low friction coefficient of only 0.1-0.2. They can increase the efficiency of mechanical operation when compared to metal materials.
Light Weight
Silicon nitride ceramics have a low theoretical density and are significantly lighter than steel and engineering super-heat-resistant alloy steel. As a result, alloy steel can be replaced with Si3N4 ceramics in situations where materials must have high strength, low density, and high temperature resistance.
Characteristics of Silicon Nitride Tube
Composition and Manufacturing
Usually, to make silicon nitride tubes, powder is compacted and then sinters at high temperatures under regulated conditions. The mechanical integrity and performance qualities of the tubes depend on their attaining a dense and homogeneous microstructure, which this manufacturing process guarantees.
Hardness and Mechanical Strength
Outstanding mechanical characteristics are one of silicon nitride tubes' distinguishing qualities. They are much more fracture tough and have a greater flexural strength than conventional ceramics like zirconia and alumina. For this reason, silicon nitride tubes are very resistant to mechanical damage and fracture even in the event of heat shock or collision.
Thermal stability
Temperature stability of silicon nitride tubes is well known. They are resistant to appreciable dimensional changes or mechanical property deterioration at temperatures over 1000°C under continuous use. Their thermal resilience makes them perfect for uses in furnaces, kilns, and thermal processing equipment where exposure to high temperatures is typical.
Chemical Resistance
Apart from its mechanical and thermal characteristics, silicon nitride tubes have outstanding chemical resistance. Their ability to withstand corrosion by acids, alkalis, and many other chemical compounds increases their usefulness in demanding industrial settings where exposure to corrosive chemicals is a worry.
Various Industries Applications
Many industries and applications make substantial use of silicon nitride tubes:
Metallurgical Industry: They are utilized in high-temperature operations like metal smelting and casting as crucibles and thermocouple protection tubes.
Technology of Semiconductors
Silicon nitride tubes are insulating elements in semiconductor wafer manufacturing and process tubes in diffusion furnaces.
Department of Energy
They are essential to many thermal management applications, including heat exchanger and combustion lining uses in gas turbine engines.
Medical and Dental
Silicon nitride tubes' biocompatibility, wear resistance, and sterilizing procedure tolerance make them useful in medical devices and implants.
