Iron titanium hydride

Saita et al. [215] used hydriding combustion synthesis for a direct production of TiFe. In the experiments, an exothermic reaction of Ti with hydrogen (Ti -i- i = TiHj + 144 kJ) was utilized for HCS of TiFe because the adiabatic flame temperature of this reaction was estimated to be 2,000°C, which is sufficiently high for melting both iron and titanium. A 1 1 molar mixture of elemental Ti and Fe pow-... 

Titanium iron hydrides are among the materials which, at the present time, appear to have potential for practical applications as an energy-storage medium (7). The formation and properties of titanium iron hydride have been studied by Reilly and Wiswall (3), who found that the reaction proceeds in two steps as indicated by Reactions 5 and 6. Both hydrides have dissociation pressures above 1 atm at room temperature in contrast to TiH2 which is very stable. Titanium iron is representative of intermetallic compounds that consist of an element (titanium) capable of forming a stable hydride and another element (iron) that is not a hydride former or at best, forms a hydride with great difficulty. Iron presumably plays a role in destabilizing the hydrides. Titanium also forms a 1 1 compound with copper (there are other intermetallic compounds in the titanium-copper system) and this fact, coupled with the observation that copper... 

Further developments in the storage and transport of hydrogen concern hydrogen in the form of hydrides of titanium/iron hydride TiFeH, 95 or magnesium/nickel hydride MgNiH4 2. 

Compared to hydride storage, with its weight problems, cryo-adsorption looked good—on paper, at least. Proponents claimed that weight could be cut by as much as one-third compared to titanium-iron hydride, but volume requirements were higher by a factor of 3. In any event, nothing much has been heard about it in recent years, and it seems to have fallen by the wayside. 

T riphenylphosphine-lodine. DESULFURIZATION Iron carbonyl. Titanium(IV) chloiide-Lithium aluminum hydride, Zinc-Chloio-methylsilane. 

One example of snch an alloy is titanium iron hydride, the last entry in Table 8.16 of the following section. In terms of mass this is not a very promising material it is the volumetric measure that is the advantage of these materials. It requires one of the lowest volumes to store 1kg in Table 8.16 certainly it is one of the lowest practical materials. It actually holds more hydrogen per unit volnme than pnre liquid hydrogen. ... 

Among catalysts derived from intermetallic compounds, titanium-iron systems have received some attention. The precise course of reactions involved is not clear. For example, it is claimed that the catalyst derived from a suitably activated TiFe intermetallic phase is TiN + Fe. The TiN is said to react with molecular hydro-gen. On the other hand, in a series of patents on Fe-Ti systems, covering a range of iron-to-titanium ratios, with or without addition transition elements, it is quite clearly regarded that the titanium is capable of forming hydrides. Whatever the mechanism, such systems appear capable of promoting ammonia synthesis in commercial yields at 300 °C, 80 atm, while some are even claimed to be active at 125 °C and 1 atm. Rare earth metals, in combination with iron, ruthenium, or cobalt, can also function as catalysts. Again, the rare earth metals seem to be... 

The interstitial carbides These are formed by the transition metals (e.g. titanium, iron) and have the general formula M, C. They are often non-stoichiometric—the carbon atoms can occupy some or all of the small spaces between the larger metal atoms, the arrangement of which remains essentially the same as in the pure metal (cf. the interstitial hydrides). 

One of the principal advantages of hydrides for hydrogen storage is safety (25). As part of a study to determine the safety of the iron—titanium—manganese metal hydride storage system, tests were conducted in conjunction with the U.S. Army (26). These tests simulated the worst possible conditions resulting from a serious coUision and demonstrated that the metal hydride vessels do not explode. 

Fig. 2. Iron—titanium hydride vessel (508 kg hydride, 6.4 kg hydrogen) performance of the Provo-Orem (Utah) bus at 3.4 MPa (493 psi) charge pressure, having 22 cylinders, each with a 75 mm dia and 1750 mm length, where (-) indicates tank pressure. To convert MPa to psi, multiply by 145. See text.

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