The Q66 will maintain its existing routing between Flushing and Long Island City. The new Q63 will also provide new Rush service along Northern Blvd.

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Even NASA scientists recognized its unique properties when silicon nitride bearings were used in the main engines of the Space Shuttle. It was identified as one of the few monolithic ceramic materials capable of surviving the severe thermal shock and thermal gradients generated in hydrogen / oxygen rocket engines and proved completely reliable throughout the entire Space Shuttle program.

Precision Ceramics stocks a range of standard silicon nitride ceramic rods, which are all precision turned to an excellent surface finish. These rods can be used as bearings, pistons, engine components, or in a variety of other assemblies. In addition, Precision Ceramics offers full machining/grinding services for custom silicon nitride component manufacturing.

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There are several different methods used to produce Silicon Nitride. Each method produces materials with slightly differing properties.

This method uses a silicon nitride powder that has been mixed with sintering aids to promote liquid phase sintering (typically yttria, magnesium oxide, and/or alumina) as well as binders to improve the mechanical strength of the green ceramic body.

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Silicon Nitride (Si3N4) has the most versatile combination of mechanical, thermal, and electrical properties of any advanced ceramic material. It is a high performance advanced ceramic that is extremely hard and has exceptional thermal shock and impact resistance. It surpasses the high temperature capabilities of most metals and has a superior combination of creep and oxidation resistance. Additionally, its low thermal conductivity and high wear resistance make it an excellent material that can withstand the toughest of conditions in the most demanding industrial applications. Silicon Nitride is an excellent choice when high-temperature and high-load abilities are needed.

Disclaimer: The values presented are mean and typical of those resulted from test samples. They are provided as an indication only to serve as guidance in the design of ceramic components and are not guaranteed in any way. The actual values can vary according to the shape and size of the envisioned component.

Silicon Nitride can be machined in green, biscuit, or fully dense states. It can be machined relatively easily into complex geometries while in the green or biscuit form. However, the sintering process that is required to fully densify the material causes the silicon nitride body to shrink approximately 20%. This shrinkage means that it is impossible to hold very tight tolerances when machining silicon nitride pre-sintering. In order to achieve very tight tolerances, fully sintered material must be machined/ground with diamond tools. This processes uses a very precise diamond coated tool/wheel to abrade away the material until the desired form is created. This can be a time-consuming and costly process due to the inherent toughness and hardness of the material.

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HPSN is produced by uniaxially pressing silicon nitride powder with sintering additives while applying heat at the same time. This process requires a special type of press and die. It produces a silicon nitride with excellent mechanical properties. However, only simple shapes can be produced. Because it is impossible to green-machine a component that is hot-pressed, diamond grinding is the only way to create complex geometries. Because of the high costs and difficulties associated with diamond grinding and hot-pressing, its use is typically limited to the production of simple components in small quantities.

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This method consolidates the silicon nitride powder by using high pressures and high temperatures. A silicon nitride body with closed porosity is isostatically pressed (uniform pressure on all sides) via an inert gas at up to 2000 bar while the chamber is simultaneously heated. This process effectively squeezes any pores/defects from the material while it is sintering and brings the density closer to theoretical. HIPing improves the mechanical properties and reliability, however, it is an expensive process that is typically only used in very select circumstances.

Unlike traditional ceramics that tend to be hard and brittle, Zirconia offers high strength, wear resistance, and flexibility far beyond those of most other technical ceramics.

Precision Ceramics stocks a range of standard silicon nitride ceramic rods, which are all precision ground to an excellent surface finish. These rods can be used as bearings, pistons, engine components, or in a variety of other assemblies. In addition, Precision Ceramics offers full machining/grinding services for custom silicon nitride component manufacturing.

This is the most popular method for producing high-strength and complex geometry silicon nitride components. This method uses a silicon nitride powder that has been mixed with sintering aids to promote liquid phase sintering (typically yttria, magnesium oxide, and/or alumina) as well as binders to improve the mechanical strength of the green ceramic body. The powder is pressed into the desired form and green-machining can take place. The parts are then placed into a furnace that has a pressurized nitrogen atmosphere to aid with densification and prevent the evaporation/decomposition of the silicon, nitrogen, and additives.

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Compared with other technical ceramics, the low thermal expansion coefficient of Silicon Nitride provides good thermal shock resistance. It is extremely hard, fracture-tough, surpasses the high temperature capabilities of most metals, and also has a superior oxidation resistance. As a consequence, silicon nitride can withstand the toughest conditions in the most demanding high-temperature and high-load applications.