Nitrides carbonitrides

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%). 

Table 3 Reaction Sequences for Nitrides, Carbonitrides and Carbides of Iron.

The field of application for GDOES is very broad and includes surface treatment studies of samples prepared by different techniques such as galvanization, nitriding, carbonitriding, carburization, diffusion, chemical and thermochemical treatments, thermic treatments, PVD and CVD coating, electrodeposition, painting, and semiconductor multilayer growth. 

For an extensive review on the elastic properties ( and v) of transition metal nitrides, carbonitrides (and carbides) as well as on the porosity correction routines the reader is referred to the tables given in [92]. Upon application and development of high-temperature investigation techniques, such as Brillouin scattering [95,96] a... 

When obtaining other refractory nitrides, carbonitrides, and compositions on their basis, mechanism and chemical stages have a similar nature [31]. 

The parameters influencing both the wave of burning and the completeness of conversion have been determined and qualitatively estimated that is the quality of final products. These data have allowed to optimize SHS-azide process of the large number of nitrides, carbonitrides, and compositions on their basis and to develop technology of their manufacture. 

The basic laws of burning of systems element-sodium azide-halide and synthesis of final refractory powders are investigated. Once the optimal technological parameters of synthesis are found, the technological process of obtaining of powders nitrides, carbonitrides, and compositions on their basis in a mode SHS-Az [12] is developed. It was found that the most appreciable influence on quality of final powders render density of reactor loading, pressure of gaseous medium, ratio of components in system, and size of particles in initial components mixture. 

In this chapter, first we summarized the investigations about nitrides and carbonitrides as cathode catalysts. Second, the stability of nitrides, carbonitrides, and oxides in acid electrolyte was discussed and introduced the applicability of oxides to support of platinum particles. Then, the necessity of modifications of oxides was described. As mentioned above, the modifications of oxides were classified into four ways, and development of oxide-based cathodes was summarized. 

The rare earth boron nitrides, carbonitrides, and borocarbonitrides are described in separate sections. The transition metal boronitrides that have been described in a previous section are interesting compounds in which superconductivity manifests. 

Compares the typical characteristics of carburizing, nitriding, carbonitriding, and ferritic nitrocarburizing... 

A hquid-phase reaction in which TiCl is reacted with hquid ammonia at —35 C to form an adduct that is subsequendy calcined at 1000°C has also been proposed (35). Preparation of titanium nitride and titanium carbonitride by the pyrolysis of titanium-containing polymer precursors has also been reported (36). 

The complex iron carbonitride is the hard component in steels that have been annealed with ammonia (nitrided steels). Complex carbonitrides with iron metals are also present in superaHoys in the form of precipitates. 

Boron-containing nonoxide amorphous or crystalline advanced ceramics, including boron nitride (BN), boron carbide (B4C), boron carbonitride (B/C/N), and boron silicon carbonitride Si/B/C/N, can be prepared via the preceramic polymers route called the polymer-derived ceramics (PDCs) route, using convenient thermal and chemical processes. Because the preparation of BN has been the most in demand and widespread boron-based material during the past two decades, this chapter provides an overview of the conversion of boron- and nitrogen-containing polymers into advanced BN materials. 

The polysilazanes were also melt spun, cured, and pyrolyzed to give silicon carbonitride fibers (Eq. 7). The carbon content of these fibers depends on the molecular composition of the polysilazane and the pyrolysis gas. When ammonia is used as reactive gas pure silicon nitride fibers will be obtained (Eq. 8) [14]. 

Carbonitride alloys, quaternary, 17 218. See also Carbonitrides Carbon nitride entries... 

Zirconium carbide, 4 649t, 686 cemented carbides, 4 656 as industrial hard carbide, 4 674 physical properties of, 4 684t preparation, 4 675, 676 stoichiometry, 4 651 Zirconium carbide nitride, 26 627 Zirconium carbonitride... 

Titanium nitride (or titanium carbonitride) previously called cyano-nitrogen titanium from titanium oxide, carbon and nitrogen, again at about 1400°C. (16). 

---