Titanium aluminum nitride

Evans R, Smith I, Munz W D, Williams K J P and Yanwood J 1996 Raman microscopic studies of ceramic coatings based on titanium aluminum nitride ICORS 96 XVth Int. Conf. on Raman Spectroscopy ed S A Asher and P B Stein (New York Wiley) pp 596-7... 

There are several vacuum processes such as physical vapor deposition (PVD) and chemical vapor deposition (CVD), sputtering, and anodic vacuum arc deposition. Materials other than metals, ie, tetraethylorthosiHcate, silane, and titanium aluminum nitride, can also be appHed. 

TAP triallyl phosphate TiALN titanium aluminum nitride... 

Subramanian B, Muraleedharan CV, Ananthakumar R, Jayachandran M. A comparative study of titanium nitride (TiN), titanium oxy nitride (TiON) and titanium aluminum nitride (TiAlN), as surface coatings for bio implants. Surf CoatTechnol 2011 205(21-22) 5014-20. 

Kraus, B.D., Moore, J.T., and DeBoer, S.J. (2002) Batch processing for semiconductor wafers to form aluminum nitride and titanium aluminum nitride. 

In the example in Figure 2.112, the thermal properties (short-term isolation) of a special titanium aluminum nitride (TIAIN) layer, which was applied in a PVD (physical vapor deposition) process, were used to hide the weld lines and adjust the gloss level in a structure-grained surface of a shifting gate cover made from PC (Polycarbonate). Figure 2.113 shows a direct comparison of surfaces that are coated and uncoated. 

Nitrides are used for wear-resistant applications, most notably surface engineering of cemented carbide cutting tools and tool steels. Titanium nitride (TiN) is the most frequently employed coating, but titanium car-bonitride (TiCN), hafnium carbide (HfC), titanium aluminum nitride (TiAlN), titanium zirconium nitride (TiZrN), and chromium nitride (CrN) have also been used commercially. These coatings are applied by vapor deposition techniques (Fig. 2). 

Magnesium reacts slowly at lower temperatures to give the amide, as do all active metals this reaction is catalyzed by transition metal ions. Aluminum nitride [24304-00-5] AIN, barium nitride [12047-79-9] Ba2N2, calcium nitride [12013-82-0] Ca2N2, strontium nitride [12033-82-8], Sr2N2, and titanium nitride [25583-20-4], TiN, may be formed by heating the corresponding amides. 

Next to Cr C2, TiC is the principal component for heat and oxidation-resistant cemented carbides. TiC-based boats, containing aluminum nitride, AIN, boron nitride, BN, and titanium boride, TiB2, have been found satisfactory for the evaporation of metals (see Boron compounds, refractory boron compounds Nitrides). 

CVD plays an increasingly important part in the design and processing of advanced electronic conductors and insulators as well as related structures, such as diffusion barriers and high thermal-conductivity substrates (heat-sinks). In these areas, materials such as titanium nitride, silicon nitride, silicon oxide, diamond, and aluminum nitride are of particular importance. These compounds are all produced by CVD. 1 1 PI... 

The combination of toxic hazard and high price (itself in part due to the extra measures needed in production processes to ensure the workers safety) has been an effective brake on commercial development of beryllium chemistry. Where possible substitute, albeit less effective, materials are often used titanium as an alternate lightweight metal or carbon fiber composites, phosphor-bronzes in place of beryllium alloys, aluminum nitride in place of BeO (1). 

In all these studies which were carried out over the five-year period, 1904-1909, the effects of catalysts on these fixations of nitrogen were investigated. For the barium compounds, iron oxide acted as a catalyst. For the titanium nitrides, various other metal oxides as well as a number of inorganic salts proved to be effective. For the silicium nitrides and aluminum nitrides, again metal oxides and salts had beneficial effects but in other proportions and to another extent than found for the titanium nitrides. Often, two or more catalysts were added to the reaction mixtures with beneficial effects, but no systematic quantitative comparisons were carried out at this time. Table I lists some of these experiments. 

A variety of other ceramics are prepared by pyrolysis of preceramic polymers.32,38 Some examples are silicon carbide, SC, tungsten carbide, WC, aluminum nitride, AIN, and titanium nitride, TiN. In some cases, these materials are obtained by simple pyrolysis in an inert atmosphere or under vacuum. In other cases a reactive atmosphere such as ammonia is needed to introduce some of the atoms required in the final product. Additional details are given in Chapter 9. 

In the following sections some examples are given of the ways in which these principles have been utilized. The first example is the use of these techniques for the low temperature preparation of oxide ceramics such as silica. This process can also be used to produce alumina, titanium oxide, or other metal oxides. The second example describes the conversion of organic polymers to carbon fiber, a process that was probably the inspiration for the later development of routes to a range of non-oxide ceramics. Following this are brief reviews of processes that lead to the formation of silicon carbide, silicon nitride, boron nitride, and aluminum nitride, plus an introduction to the synthesis of other ceramics such as phosphorus nitride, nitrogen-phosphorus-boron materials, and an example of a transition metal-containing ceramic material. 

These results also support the theoretical explanation of the synthesis of titanium nitride and aluminum nitride given above. They show that metal chlorides can be decomposed and metals deposited in the intense low pressure plasma under similar conditions as those employed for the synthesis of nitrides. The interpretation of the experimental results given in Ref.33 can now be considered as the initial step in the development of the ideas presented in this review (see also30 ). 

Metals and ceramics (claylike materials) are also used as matrices in advanced composites. In most cases, metal matrix composites consist of aluminum, magnesium, copper, or titanium alloys of these metals or intermetallic compounds, such as TiAl and NiAl. The reinforcement is usually a ceramic material such as boron carbide (B4C), silicon carbide (SiC), aluminum oxide (A1203), aluminum nitride (AlN), or boron nitride (BN). Metals have also been used as reinforcements in metal matrices. For example, the physical characteristics of some types of steel have been improved by the addition of aluminum fibers. The reinforcement is usually added in the form of particles, whiskers, plates, or fibers. 

Thermal Evaporation The easiest way of evaporating metal is by means of resistance evaporators known commonly as boats . Boats, made of sintered ceramics, are positioned side by side at a distance of approximately 10 cm across the web width (Fig. 8.1). Titanium boride TiB2 is used as an electrically conductive material with boron nitride BN (two-component evaporator) or BN and aluminum nitride AIN (three-component evaporator) as an insulating material [2]. By combination of conductive and insulating materials, the electrical properties of evaporators are adjusted. 

More than one boride phase can be formed with most metals, and in many cases a continuous series of solid solutions may be formed. Several methods have been used for the relatively large-scale preparation of metal borides. One that is commonly used is carbon reduction of boric oxide and the appropriate metal oxide at temperatures up to 2000 °C. Fused salt electrolysis of borax or boric oxide and a metal oxide at 700 1000 °C have also been used. Small-scale methods available include direct reaction of the elements at temperatures above 1000 °C and the reaction of elemental boron with metal oxides at temperatures approaching 2000 °C. One commercial use of borides is in titanium boride-aluminum nitride crucibles or boats for evaporation of aluminum by resistance heating in the aluminizing process, and for rare earth hexaborides as electronic cathodes. Borides have also been used in sliding electrical contacts and as cathodes in HaU cells for aluminum processing. 

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. 

All precursors are amorphous up to calcination temperatures of around 600°C. At higher temperatures, in most cases powders with extremely small crystallite sizes of around 20-40 nm are formed (Fig. 7). A further increase in calcination temperature promotes crystal growth. With aluminum nitride, a white powder with a low oxygen and carbon content is obtained [97]. Other main group element precursors exhibit fairly different behaviors Mg and Ca precursors yield metal cyanamide [99]. Calcination of the transition element precursors (Fig. 8) results in the formation of nitrides, carbonitrides, or carbides. For the titanium-containing precursors, TiN/TiC solid solutions can be obtained [96] the quantity of carbon strongly depends on the calcination atmosphere applied (argon, 31 wt% ammonia, 5.1 wt%). 

Aluminum is used as the anode and nichrome as the cathode. There is also available in the cell a catalytic amount of titanium for fixation purposes, in addition to naphthalene, which serves a purpose again in the reduction stage. The electrolyte is tetrabutylammonium chloride. Aluminum isopropoxide increases the over-all efliciency and turns this process into a catalytic one. This system starts with titanium tetraiso-propoxide. Reduction takes place, presumably again to the titanium (II) level. We have evidence from electrochemical experiments that titanium (II) is produced and involved in the fixation. Titanium (II), once formed, picks up N2 from the atmosphere and forms the complex, which then is available for reduction by sodium naphthalenide. Naphthalene is present in a catalytic amount and is reduced at the cathode to the radical anion. In this experiment, one can actually see it as a greenish color at the cathode. Naphthalenide reduces the No compound, producing the nitride. Normally, the reaction would stop at this point. We believe that in the electrochemical process, aluminum (III) abstracts nitride from titanium and forms aluminum nitride. This nitride transfer also can be observed in nonelectrolytic reactions. Thus, aluminum nitride is stored and ammonia is available at any time, merely by protonation. Both titanium and naphthalene are catalytic and permit operation of an over-all catalytic process. 

Nitrogen concentration in the crystals decrease with increasing amounts of aluminum or titanium added to the solvent/catalyst (Fig. 15). Even when large amounts of aluminum are added, it is difficult to achieve purity levels of less than 0.1 p.p.m. nitrogen. This is to be expected as the aluminum nitrides are believed to readily decompose, whilst titanium nitrides are not readily decomposed, making titanium... 

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