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Crucible Materials
Published in Nagaiyar Krishnamurthy, Metal–Crucible Interactions, 2023
Silicon nitride has high strength and high hardness due to strong covalent bonds. These bonds also make sintering difficult. In 1961, Deeley et al. achieved high densities by hot pressing previously formed silicon nitride powder using sintering additives. Using magnesium oxide, full density was reached by hot pressing at 1850°C under 23 MPa. The strength of this material was substantially better than that of RBSN.
Ceramic Armour
Published in Paul J. Hazell, Armour, 2023
Silicon nitride (Si3N4), like silicon carbide, can be formed through the reaction bonding process where shaped silicon powder is fired in a nitrogen-rich environment. However, the porosity of the product manufactured in this way is relatively high and therefore renders the material inappropriate for ballistic applications. Nevertheless, silicon nitride can be sintered or hot pressed and has found some niche applications in defeating small arms. However, against hard-cored AP projectiles, its performance is similar to a high-quality alumina.
Ternary Adamantine Semiconductors
Published in Lev I. Berger, Semiconductor Materials, 2020
Applications of Si3N4 are as an insulating diffusion mask in microelectronic technology; the nonelectronic applications are as a matrix material for ceramic composites and a material for machine tools, bearings, and some engine parts. The utilization of many potential applications is still somewhat limited by the lack of toughness of the silicon nitride films and reliability of the technology of their preparation.6.177
Effect of silicon nitride microstructure on characteristics of FSW tool for steel and tool life
Published in Welding International, 2023
Kai Funaki, Yoshiaki Morisada, Takayuki Fukasawa, Yutaka Abe, Hidetoshi Fujii
In this study, we focused on silicon nitride as a material whose main raw material is inexpensive and has excellent high-temperature properties. Silicon nitride materials are widely used in product fields where wear resistance and high-temperature properties are required. The most common applications are bearing balls used in high-load environments such as machine tools and products requiring a certain level of reliability such as aircrafts and automobiles [8,9]. Other applications include radar dome materials that take advantage of their high-temperature properties, brake materials for elevator emergency stops [10], bearing balls for wind turbine generators and fan motors that take advantage of their insulating properties, and insulating substrates for power modules used in automobiles.
Effect of nitrogen gas pressure during heat treatment on the morphology of silicon nitride fibers synthesized by carbothermal nitridation
Published in Journal of Asian Ceramic Societies, 2018
Sotaro Baba, Tomoyo Goto, Sung Hun Cho, Tohru Sekino
Silicon nitride (Si3N4) ceramics have high strength, high toughness, low density, excellent high-temperature strength and a low dielectric constant. Si3N4 is therefore widely used as a structural material in turbocharger rotors, ball bearings, cutting tools, etc. On the other hand, one-dimensional silicon nitride nanomaterials such as fibers and whiskers have many special applications. They are used as reinforcing fibers in various matrices such as resins, metals and ceramics, for example, to improve their mechanical and thermal properties. Hirao et al. [1] produced an oriented Si3N4 whisker-reinforced composite Si3N4 matrix combining high strength and toughness. Kusunose et al. [2] produced an epoxy/Si3N4 nanowire composite that improved thermal conductivity. To develop higher-performance materials using silicon nitride fibers, it is necessary to control the structure of the bulk materials precisely; thus, morphology and crystalline phase control of the silicon nitride fibers is very important.
Mechanical Properties and Unlubricated Sliding Wear Behavior Study of Silicon Nitride-Based Cermets
Published in Tribology Transactions, 2022
Sushree Sefali Mishra, Debasis Chaira
Silicon nitride (Si3N4) has a unique combination of high-temperature hardness and strength with acceptable toughness, chemical inertness, low density, and excellent thermal shock resistance. Hence, it is widely used as a wear-resistant material (1–8). It has a wide variety of engineering applications that involve metallic surface contact, such as cutting and forming tools, die drawing, roller bearings, and automotive or aerospace engine parts (2, 3). Silicon nitride is well known for its use in bearing systems as a ball component under lubricated conditions. However, the sliding contact of Si3N4 under dry conditions produces a high wear rate. This is due to the intrinsic brittle nature of the ceramic, which affects the abrasive wear (9). It has been reported that incorporation of β-Si3N4 whiskers or some metallic phases into Si3N4 ceramics improves the toughness and wear properties compared to monolithic Si3N4 in both dry and lubricated conditions (10). There has also been investigation of the mechanical properties of Si3N4 ceramics being improved by a suitable selection of sintering additives and reinforcing elements (11–13). For better performance of monolithic Si3N4- or Si3N4-based cermet, the effects of wear parameters and microstructures of materials are very important. Several factors, such as friction force, normal load, sliding velocity, atmospheric humidity, characteristics of friction pairs, and so on, play an essential role in wear behavior (5, 6, 14).