Nitrides refractory

Smith, P. M., et al., Chemical Vapor Deposition of Ternary Refractory Nitrides for Difiusion Barrier Applications, Proc. 13th. Int. Conf. on VLSI Multilevel Interconnections, Sandia National Labs., Albuquerque, NM (1996)... 

Other useful refractory nitrides for corrosion protection are silicon nitride (Si3N4) and boron nitride (BN). Silicon nitride has good corrosion resistance and is not attacked by most molten metals as shown in Table 17.6 (see Ch. 10). 

In the field of high-temperature combustion synthesis, metals have been reacted with nitrogen, both in the gaseous and liquid phases, to form refractory nitrides [2], In most cases, this nitriding process is heterogeneous. 

Diamond Hints, although not approaching bulk diamond, are harder than most refractory nitride and carbide thin films, which makes them attractive for tribological coatings. Transparency in the visible and infrared regions of the optical spectrum can be maintained and index-of-refraction values approaching that of bulk diamond have been measured. Electrical resistivities of diamond films have been produced within the full range of bulk diamond, and thermal conductivities equivalent to those of bulk diamond also have been achieved. As substrates for semiconductor electronic devices, diamond films can be produced by both the PACVD and IBRD techniques. 

A theoretical analysis of combustion synthesis of refractory nitrides was presented by Munir and Holt in 1987.37 They predicted the existence of an activation energy due to chemical reaction or mass-transport. Glassman et al. in 1987,38 in their thermodynamic analysis of TiN formation, examined the possibility of creating TiN by a self-sustained reaction of the metal particles and nitrogen gas in a rocket motor. They reported that for the stoichiometric ratio of 0.5 mole N2/mole titanium, the reaction has... 

The nitrides and carbides of titanium and zirconium and the carbide of hafnium are extremely hard substances, resembling metals both in appearance and in electrical conductivity. Their formulae approach AxBh but some departure from stoichiometry is possible. Each of these refractory substances has the sodium chloride structure, described alternately (p. 190) as cubic close-packed arrays of metal atoms with the small nonmetal atoms in the octahedral holes. Note, however, that the parent metals themselves do not have cubic close-packed structures. Thus, the older view of such nitrides and carbides as lattices of the parent metals that are expanded to accommodate nitrogen or carbon atoms in the holes (interstices) is not admissible. The nature of the bonding in such refractory nitrides and carbides appears to be linked to the nature of bonding in metals in general, an important and interesting topic, but best pursued in more advanced works. 

McLaine LA, Coppel CP, Little AD (1966) Equilibrium studies of refractory nitrides. 

S. Zhang and Z. A. Munir, The combustion synthesis of refractory nitrides Part II, the synthesis of niobium nitride, J. Mater. Sci. 1991, 26, 3380-3385. 

The experimental researches by definition of the mechanism and laws of SHS-Az various refractory nitrides and carbonitrides are carried out. It was discovered that the burning of azide SHS systems has in most cases been complex in nature. 

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

Complex halides of nitrided elements were similarly used to obtain other refractory nitrides such as silicon, boron, and aluminum nitrides. In this case, the following chemical reactions with the stoichiometric component ratio (n = 1) were used ... 

Synthesis Refractory Nitrides in a Mode of Burning with Solid Nitriding Reagents/Reffactory Nitrides, Naukova Dumka, Kiev, pp. 27-30 (in Russian). 

The refractory nitrides are in many respects similar to the refractory carbides. They are hard and wear-resistant with high melting points and good chemical resistance. They are important industrial materials and have a significant number of major applications in cutting and grinding tools, wear surfaces, semiconductors, and others. 

This chapter is a review of the general characteristics of the refixictory nitrides and their classification. Like the refiactory carbides (see Ch. 2), the refractory nitrides can be divided into two major types the interstitial nitrides reviewed in Chs. 10 and 11 and the covalent nitrides, reviewed in Chs. 12 and 13. 

This difference is large with the interstitial nitrides (Ti-N 1.5, V-N 1.4, Zr-N 1.6, Nb-N 1.4, Hf-N 1.7, Ta-N 1.5) but less pronounced with the covalentnitrides(B-N 1.0, Al-N 1.5, Si-N 1.2). Since nitrogen has a higher electronegativity than carbon, refractory nitrides show a greater electronegativity difference than the equivalent carbides. 

As mentioned in Ch. 9, the refractory nitrides consist of two structurally different types generally known as interstitial and covalent nitrides. This chapter provides a general review of the structural characteristics and composition of the interstitial nitrides and follows the outline of Ch. 3, Interstitial Carbides Structure and Composition. Some of these interstitial nitrides, titanium nitride in particular, are major industrial materials. 

The observations on thermal expansion of refractory carbides in Sec. 2.0 of Ch. 4 are applicable to the refractory nitrides. Table 11.3 shows that generally the higher the bond energy of the compound, the lower the expansion. 

Refractory Nitrides. The various chemical preparation reactions for refractory nitride powders are summarized in Table 14.3.[2][5][i2]-[i6]... 

Table 14.3 Chemical Preparation of Refractory Nitride Powders...

As shown in the table, most refractory nitride powders may be produced by the reaction of the metal halide with ammonia. Another common production method is the reaction of an oxyhalide (i.e., Cr02Cl2),... 

How much of an impact CVD carbide and nitride powders will have is not clear at this time since applications have yet to reach the commercial stage in any significant manner. Still, the success of a number of development programs strongly suggests that CVD may soon become a major powder-production technology. This is already evident in Japan which is a recognized leader, particularly in refractory nitrides. 

The adiabatic temperature iJad) of the compound, i.e., the processing temperature at which no heat enters or leaves the system, can be used as an indication of the temperature at the combustion front. As shown in Table 14.4, this temperature can be very high, particularly with the refractory nitrides. 

All refractory nitrides can be produced as coatings by CVD and, for most of them, CVD remains a major production process. CVD titanium nitride (TiN) is the most important nitride coating from an application standpoint. It is used extensively mainly for wear- and erosion-resistant applications and as a difrusion barrier and antireflection coating in semiconductor devices.l l... 

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