Aluminum nitride applications

Aluminum alkoxides, polymerizations of poly[bis(methoxyethoxyethoxy)phos-phazene] molecular composites, 258-266 Aluminum nitride applications, 427... 

The major application of CVD aluminum nitride is for electronic components. At this time, most of the AIN powder is produced by CVD and originates in Japan and is used by the Japanese industry.b l... 

A GaN substrate would be a help in this respect but it would need to be semi-insulating. In addition, GaN has a poor thermal conductivity and is not very suitable due to this negative material property. Aluminum nitride substrates may become the substrate of choice for GaN high-frequency applications. It has a reasonable thermal conductivity and is intrinsically semi-insulating but only time will tell. 

Besides the continuous fibers, application of metallorganic polymers to heat-resistant coatings, dense ceramic moldings, porous bodies, and SiC matrix sources in advanced ceramics via polymer infiltration pyrolysis (PIP) have been developed. Novel precursor polymers have been synthesized and investigated for ceramics in addition to PCS (Table 19.1). For SiC ceramics, various Si-C backbone polymers have been synthesized. Their polymer nature (e.g., viscosity, stability, cross-linking mechanism, and ceramic yield) are, however, fairly different from PCS. On the other hand, polysilazane, perhydropolysilazane, polyb-orazine, aluminum nitride polymers, and their copolymers have been investigated... 

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. 

Typical fillers carbon fiber, glass fiber, graphite lubricant for wear resistant applications molybdenum sulfide, PTFE. antimony trioxide, barium titanate, clay, silica, aluminum nitride, smectite... 

The transamination route employed for the CVD growth of Si3N4 (Sect. 5.5.1) and AIN (Sect. 5.5.2) are also applicable for ZriN4 [202], Hf3N4, andTa3Ns [203], As with aluminum nitride, deposition occurs at temperatures significantly lower than those reported for traditional CVD routes. In each case the homoleptic amido compounds (25 and 26) were employed as the precursors. 

Thermally conductive adhesives may be filled with metal, ceramic, or inorganic particles. Silver-filled epoxies have high thermal conductivities, but may not be used where there is a risk of electrical shorting. In such cases, epoxies or other polymers filled with electrically resistive, but thermally conductive materials such as aluminum nitride, boron nitride, alumina, or beryllia must be used. Some applications for thermally conductive adhesives include attachment of power devices, heat sinks, large components such as capacitors and transformers, large ceramic substrates, and edge connectors. 

Electronic ceramics include barium titanate (BaTiOs), zinc oxide (ZnO), lead zirconate titanate [Pb(ZrJ ii ()03], aluminum nitride (AIN), and HTSCs. They are used in applications as diverse as capacitor dielectrics, varistors. 

Many of the applications of AIN require it to be in consolidated in the form of substrates or crucibles. It is an electrical insulator and has a high thermal conductivity (better than Fe), which makes it attractive for use in electronic packaging. Aluminum nitride crucibles are used to contain metal melts and molten salts. 

I 9 AIN Ceramics from Nanosized Plasma Processed Powder, its Properties and Application Table 9.1 Characteristics of aluminum nitride ceramics. 

The most efficient alloying elements for improving oxidation resistance of iron in air are chromium and aluminum. Use of these elements with additional alloyed nickel and silicon is especially effective. An 8% Al-Fe alloy is reported to have the same oxidation resistance as a 20% Cr-80% Ni alloy [51]. Unfortunately, the poor mechanical properties of aluminum-iron alloys, the sensitivity of their protective oxide scales to damage, and the tendency to form aluminum nitride that causes embrittlement have combined to limit their application as oxidation-resistant materials. In combination with chromium, some of these drawbacks of aluminum-iron alloys are overcome. 

Aluminum nitride (AlN) has interesting properties, such as a high thermal conductivity (70-210 W m for the polycrystalline material, and up to 285 W m for single crystals), a high volume resistance, and moderate dielectric properties. The thermal expansion coefficient of AlN is close to that of silicon, and it is one of the most mechanically strong and thermally stable ceramics. These excellent attributes make AlN a useful material for many applications [160, 161]. 

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