Technical progress depends on materials that allow the manufacture of powerful components and systems. Silicon nitride (Si3N4) is one such a material. The high-performance ceramic features a combination of exceptional properties but also imposes high requirements on the manufacturing process.
Silicon nitride is a highly resistant material used in lightweight construction and high-temperature applications. It is an ideal option for components previously made of steel, when high temperature stability combined with low weight, resistance to corrosive influences as well as abrasion resistance are required.
Si3N4 was developed for industrial use during the second half of the last century. At that time, it was necessary to find an alternative to metallic materials used in turbines or combustion engines exposed to mechanical and thermal stresses that would allow higher operating temperatures and increased efficiency. High requirements imposed on processing i.e. production of powdered raw materials, shaping, sintering and high cost, are the reasons that the material has mostly been used for specific applications until now.
With a low density of 3.2 to 3.3 g cm–³, silicon nitride is almost as light as aluminum with 2.7 g cm–³ and a bending strength of up to 1000 MPa. In addition, Si3N4 is characterized by high resistance to wear and exceeds high-temperature properties of most metals such as high-temperature strength and creep resistance.
Other features are its low coefficient of thermal expansion resulting in very high thermal shock resistance as well as high fracture toughness (7 MPam1/2). Therefore, workpieces made of Si3N4 are insensitive to shocks and impacts. These workpieces withstand operating temperatures up to 1300° C, and are resistant to corrosive effects and chemicals such as acids and alkaline solutions or special molten metals such as aluminum.
All these properties make silicon nitride ideal for use with components exhibiting high mechanical strength even when exposed to sudden stresses and showing consistent resistance to high operational temperatures, corrosive media and heavy wear.
The company Sembach specializes in ceramics and has gained extensive experience in the construction, shaping and manufacture of workpieces made of high-performance ceramics over the course of many decades. Using injection molding, dry pressing and 5-axis milling, Sembach efficiently manufacture complex shaped prototypes and large-batch components of silicon nitride (SSN). As the company stated, it is ready to participate in the development and opening up of new applications for silicon nitride, a high class, high-performance ceramic material thanks to its varied properties.
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