Nitrides ternary compounds

The most important application of the LP measurements is establishing the chemical composition of the ternary compounds. For nitrides, a standard accuracy of X-ray measurements of about 10 ppm would allow us to determine the composition with an error of about 0.1%. Unfortunately, lack of reliable data for elastic parameters of all nitrides and for lattice parameters of AIN and InN leads to a lowering of this accuracy to about 1%. 

Ternary phases with structures different from those of the phases of the binary boundary systems are more the exception than the rule. Such phases have been reported in the systems Nb-Mo-N, Ta-Mo-N, Nb-Ta-N, Zr-V-N, Nb-Cr-N, and Ta-Cr-N. Information about ternary transition metal-nitrogen systems is often available for specific temperatmes only. This is even more the case for quaternary nitride systems, which play a role in the production of carbonitride cermets where quaternary compounds of the types (Ti,Mo)(C,N) and (Ti,W)(C,N) are of interest (see Carbides Transition Metal Solid-state Chemistry), as well as in layer technology where titanium nitride-based coatings of the type Ti(C,B,N) are prepared by magnetron sputtering. Layers consisting of ternary compounds of the type (Ti,Al)N and (Ti,V)N also have favorable properties with respect to abrasion resistance. 

Scheme 1. Synthesis of a ternary compound by reaction of the respective metal oxide/nitride and the nonmetal oxide/nitride.

Binary and Ternary Compounds with Elements of Groups II, III, and V. 2f-ray electron spectroscopy has been used to probe the electronic structures of tungsten borides, nitrides and also some carbides and oxides. Enthalpies of formation AH°298.i5 the tungsten borides WB and W2B have been determined by fluorine calorimetry and are — 66.5 and — 68.2 kJ mol respectively. The theoretical possibilities of preparing M02B, a-MoB, MO2B5, WjB, a-WB, and W2B5 by chemical vapour deposition is discussed and MoXj (X = B or Be) have been prepared and examined by X-ray methods. ... 

U.S. Bureau of Mines Bull. 672, 674, and 677. Bulletins 672 and 674 cover the elements, binary oxides and binary halides in a very complete fashion. Bulletin 677, summarizes the values from Bulletins 672 and 674, and adds a modest selection of tables for arsenides, antimonides, borides, carbides, carbonates, hydrides, nitrides, phosphides, selenides, silicates, silicides, sulfates, sulfides and tellurides. The coverage of these added compound types, however, is far from complete for example, there are no tables for PbS04, SnS04, GaS and Li2S. The only ternary compounds included are the carbonates, sulfates and silicates, and no quaternary compounds are listed except for a limited number of hydrated compounds. Only brief references are given to the data sources, without attempt to explain the choice between conflicting values. 

Figure 26. The crystal structures of y -Fc4N and Ti3AlN (space group Pm3m). In the binary nitride the nitrogen atoms occupy one quarter of the octahedral voids formed by the cubic close-packed iron atoms. In the ternary compound the nitrogen atoms fill those octahedral voids which are formed solely by the titanium atoms.

Corrosion by Metals Reactions of Si3N4 with metals and alloys are a complex issue, because the atmosphere both for oxygen and nitrogen partial pressures plays a role and silicides, nitrides, or ternary compounds can form. A good compilation of the partly conflicting observations has been provided [116], For the interaction of the related SiAlONs and Fe-based alloys see published work [124]. 

In addition to binary compounds made with elements from the 2d period, ternary compounds may also exhibit higher thermal stability that diamond [218]. Such compounds can be considered as solid solutions of carbon in boron nitride. Efforts to synthesize such compounds have been made both at low and at high pressures. 

Attempts have also been made to electrodeposit elemental semiconductors like silicon [8], as well as compound semiconductors like III-V nitrides [9]. Other II-VI semiconductors like CdS [10], ZnSe [11], ZnTe [12-14], and ZnO [15,16] as well as SnS [17], which is a IV-VI compound semiconductor, have also been electrodeposited in addition to ternary compounds like CuInSe2 [18-22] and quaternary compounds like CuInGaSe2 [23-26] and Cu2ZnSnS4 [27]. 

A continuous series of solid solutions forms between fee LaN and ThN at 1700 C [4] and at 1900°C [1] with only a small negative deviation from the Vegard rule in LaN-rich solutions. No ternary compound exists at 1200°C and Ng pressures up to 30 atm, at which pressure the solid solution decomposes into the binary nitrides ThgNa (sic, probably Th3N4) and LaN [4]. A miscibility gap is predicted with the calculated critical point of 1450 K [2]. 

While most of the binary carbides and nitrides considered above form unlimited homogeneous solid solutions, some other 5 and p elements (B, Be, Al, Mg, etc.) have only a low solubility in these phases. As their content in carbides and nitrides increases, ternary compounds with very specific crystal structures are formed which were reviewed by Alyamovsky et al (1981) and Goldschmidt (1967). It is well known (see Samsonov, Serebryakov and Neronov (1975)) that B or transition metal borides do not form unlimited solid solutions, when interacting with MX phases (X = C, N) and single-phase TiNjBj, compounds exist over a narrow composition range for example, when z + y = 0.62-0.94, y < 0.03 (see Alyamovsky, Zainulin and Shveikin (1976)). As the B/N ratio increases. 

Synthetic routes derived from molecular and non-molecular precursors have expedited the development of technologically important 2- and 3- dimensional materials. Such approaches have often proved superior to conventional ceramic techniques in that high purity bulk samples or thin films can be prepared at lower temperatures much more rapidly. Predominant among the precursor methods are those based on decomposition reactions. These either involve gaseous species, such as those used in chemical vapor deposition (CVD), or solids. Examples include the pyrolysis of the gas-phase precursor [(CH3)2A1(NH2)]3 to produce aluminum nitride (i) and the thermal decomposition of solid state carbonate precursors of calcium and manganese (Cai j,Mn C03, 0 < x < 1) to produce several of the known ternary compounds in the Ca-Mn-O system (2). Single-displacement reactions are also common as precursor methods. These approaches usually involve gas-phase reactions and are also used in CVD techniques. Examples here include the formation oi... 

Ceramic superconducting films are divided into three classes, Bl-type compounds, ternary compounds, and high-temperature oxide superconductors. The Bl-type (NaCl-type structure) compound superconductors consist of nitrides and carbides with 5A, 6A, and 7A transition metals, such as TiN, ZrN, HfN, VN, NbN TaN, MoN, WN, TiC, ZrC, HfC, VC, NbC, TaC, MoC, WC, NbNi tC t, hex-MoN, and hex-MoC. Regarding the thin-film material, it is notable that NbN and NbN] (C ( (x = 0.08 and 0.15) have superconducting critical temperature, T, values of 17.3 and 17.8 K, respectively. The deposition method used is almost always sputtering or CVD. The properties of films deposited by the former method are superior. A highly reliable Josephson device was realized with an NbN film. 

Among cerium-containing nitride-type compounds, ternary nitrides in which Ce is tetravalent are formed with electropositive metals such as lithium or barium. These hygroscopic compounds are essentially ionic in character. In addition, oxynitrides containing cerium and barium are also known. However, surprisingly, no ionic ternary nitride (or quaternary oxynitride) involving other R elements has been described. 

Klesnar and Rogl (1992) have also studied phase relations and phase stabilities at T = 1400°C in the ternary systems R-B-N where R is Nd, Sm or Gd in this case ternary compounds are found to be stable. Three different stoichiometries were observed with these early lanthanides RBN2, R3B2N4 and Ri5Bg(N,0)25. In addition, Kikkawa et al. (1997) have recently reported the preparation under high pressure of another orthorhombic La-B-N phase. All these ternary lanthanide boron(oxy)nitrides are rather unstable under moist conditions. 

PrBN2-type. The existence of ternary compounds associating nitrogen, boron and a lanthanide was first mentioned by Gaude (1983) with the RBN2 nitrides (R = Nd, Sm),... 

Dr. Roger Marchand from the CNRS in the University of Rennes reviews ternary and higher order nitride materials in chapter 166. The synthesis of ternary compounds is reviewed and the products are categorized by their composition and the nature of the chemical bonding they exhibit. The structures of the compounds are discussed where possible. The consequences of the chemical properties for the physical properties are considered wherever studies have been made. 

Phosphides. Compounds of phosphoms containing the more electropositive elements are generally called phosphides. A large number of binary phosphides as well as many ternary mixed-metal phosphides, metal phosphide nitrides, etc, are known. Some binary phosphides, such as those of nickel, exhibit a variety of stoichiometries (Ni P, Ni P2, Nq2P5, Ni2P, Ni P, NiP, NiP2, NiP ), whereas others, such as aluminum, form only one (AlP). Metalloids such as B and Si also form phosphides. 

Figure 7.15 (a) Enthalpy of formation of ternary oxides and nitrides from their binary constituent compounds as a function of the ratio of ionic potential [16]. Reprinted with permission from [16] Copyright (1997) American Chemical Society, (b) Gibbs energy of the oxide-sulfide equilibrium for group 1 and 2 metals at 1773 K as a function of the optical basicity of the metal. 

Most known quaternary nitrides contain lithium and are synthesized by reacting a lithium-containing ternary nitride with a metal or metal nitride (Table 8.1, Equation 5). Many of the quaternary nitrides reported also may be synthesized by the reaction of the elements either under N2 or with Li3N. Very few true quaternary compounds are known, and further studies of ternary systems are needed before advances in the synthesis of quaternary systems can be realized. 

---