Nitriding of metals

Nitrides of Metals of the First Transition Series R. Juza... 

Hydrolysis of the nitride of a metal. The nitrides of metals such as magnesium react with water to produce ammonia and the hydroxide of the metal thus ... 

In the remaining part of this chapter one such approach, the nitriding of metal surfaces, will be discussed in some detail since it could lead both to higher ion fractions and to a lower effective-Z than that of the pure metal. 

Fluid-solid reactions include thermal decomposition of minerals, roasting (oxidation) of sulfide ores, reduction of metal oxides with hydrogen, nitridation of metals, and carburization of metals. Each t3 e of reaction will be discussed finm the thermodynamic point of view. Then reaction kinetics for all of the various rate determining steps in fluid-sohd reactions will be discussed for two general models shrinking core and shrinking particle. 

The direct nitridation of metal powders is commonly used to produce... 

These two issues have contributed to extensive research on metal-organic precursors for the deposition of nitrides of metals in groups III-V. There has been considerable interest, as well as progress, in CVD of GaN and AIN because these materials have been in the technological spotlight recently, and their depositions involve similar chemistry. The synthesis of new precursors continues to proceed at a high rate. The precursor strategies that have resulted are summarized in several recent review articles " . 

The formation of silicon nitride whiskers was observed in several different reactions, including vapor deposition, CVD, and growth from a melt. However, only the following techniques are considered to have commercial significance nitriding of metallic silicon or silicon-silica mixture, carbothermal reduction of silica with simultaneous nitridation, and thermal decomposition of silicon halides. 

Other synthesis methods have also been developed but may not be practiced on a large commercial scale as compared to those indicated above. Examples of syntheses that begin from liquid phase precursors include the sol-gel, hydrothermal, and Pechini methods. In the course of these reaction schemes, polycondensation or precipitation occurs, and the volatile components are removed, often by thermal methods. Other synthesis routes to ceramic materials include the nitridation of metals to form metal nitrides and the carbothermal reduction of oxides to form carbides and borides. 

Transition metal nitrides can be prepared easily by nitridation of metals, oxides, and other precursors containing the transition metal (e.g. sodium or ammonium salts) ... 

Interstitial alloys are formed between metals and non-metaUic or semi-metallic elements such as boron, phosphorus, carbon and nitrogen the latter occupy holes in the metal structure, which may however have to expand or re-arrange to accommodate them. Carbides and nitrides of metals of the first Transition Series form spontaneously during catalytic reactions where the reactants contain these atoms, and are themselves catalytically active. They do not exist as stable compounds of the noble metals of Groups 8 to 10. 

Wirth et al. [72] have examined a range of materials including tantalum nitride (TajNg), aluminum nitride, and titanium nitride for their performance in the HER reaction. AIN and TiN were synthesized by direct nitridation of metallic Al or Ti using Nj at temperatures above 1000 C whilst TajNg was a commercial sample. This synthetic route resulted in low surface area nitrides which was intended as... 

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