Structural application, silicon nitrides

Applications. Silicon nitride is die leading material for components in advanced automotive, diesel, and gas turbine engines. The range of potentially useful ceramic parts includes both static structural components and dynamic ones such as turbocharger rotors, gasifier turbine rotors, valves, valve guides, valve seats, piston components, cam followers, fuel injector links, and bearings. Some of these parts have been commercialized, others are... 

The market for silicon nitride is fast growing, particularly in structural and chemical resistance applications and as a thin film in semiconductor devices.P 1... 

Non-oxide ceramics such as silicon carbide (SiC), silicon nitride (SijN ), and boron nitride (BN) offer a wide variety of unique physical properties such as high hardness and high structural stability under environmental extremes, as well as varied electronic and optical properties. These advantageous properties provide the driving force for intense research efforts directed toward developing new practical applications for these materials. These efforts occur despite the considerable expense often associated with their initial preparation and subsequent transformation into finished products. 

This type of material is commonly used in the production of semiconductor devices.57 The silica layer is used as a starting layer for integrated circuit (IC) build-up. IC layer materials range from single crystals and doped polycrystalline silicon, silicon nitride, thermally-grown oxide to vapour deposited or sputtered metal or metal silicide layers. Structural adhesion of the various layers is obtained by the application of organosilanes, such as AEAPTS, APTS and GPTS. 

Since their mechanical properties are maintained at high temperatures (up to 1700 K), silicon nitride-based materials are attractive for use in high-temperature structural applications in chemically aggressive environments. For example, several properties of a Si3N4-based ceramic (Si3N4-l-SiC+TiN), suitable for ceramic engines, are shown in Table Vm. 

Non-oxide ceramic materials such as silicon carbide has been used commercially as a membrane support material and studied as a potential membrane material. Silicon nitride has also the potential of being a ceramic membrane material. In fact, both materials have been used in other high-temperature structural ceramic applications. Oxidation resistance of these non-oxide ceramics as membrane materials for membrane reactor applications is obviously very important. The oxidation rate is related to the reactive surface area thus oxidation of porous non-oxide ceramics depends on their open porosity. The generally accepted oxidation mechanism of porous silicon nitride materials consists of two... 

Numerous ceramics are deposited via chemical vapor deposition. Oxide, carbide, nitride, and boride films can all be produced from gas phase precursors. This section gives details on the production-scale reactions for materials that are widely produced. In addition, a survey of the latest research including novel precursors and chemical reactions is provided. The discussion begins with the mature technologies of silicon dioxide, aluminum oxide, and silicon nitride CVD. Then the focus turns to the deposition of thin films having characteristics that are attractive for future applications in microelectronics, micromachinery, and hard coatings for tools and parts. These materials include aluminum nitride, boron nitride, titanium nitride, titanium dioxide, silicon carbide, and mixed-metal oxides such as those of the perovskite structure and those used as high To superconductors. 

Silicon nitride ceramics are one of the most promising materials for structural applications. The properties of the silicon nitride ceramics depend on the phases present and their microstructures. This paper describes how to approach microstructural design of these materials by using the phase equilibrium diagrams of silicon nitride-metal oxide systems. 

Silicon nitride (Si3N4) has received considerable research and development interest because it has high mechanical properties, electronic properties, low density and corrosive resistance at high temperatures. It can be widely used in structural and functional applications. The CVD process is an effective technique to manufacture silicon nitride materials with ultra-high-purity and unique properties. 

Silicon nitride (see Nitrides) is a key material for structural ceramic applications in environments of high mechanical and thermal stress such as in vehicular propulsion engines. Properties which make this material uniquely suitable are high mechanical strength at room and elevated temperatures, good oxidation and creep resistance at high temperatures, high thermal shock resistance, excellent abrasion and corrosion resistance, low density, and, consequendy, alow moment of inertia. Additionally, silicon nitride is made from abundant raw materials. 

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