Nitrides


Also found in: Dictionary, Thesaurus, Medical.

Nitrides

 

compounds of nitrogen with more electropositive elements, mainly metals. The following groups of nitrides are distinguished on the basis of structure and properties:

(1) The saltlike nitrides of metals of Groups I and II of the Mendeleev periodic table; they are easily decomposed by water with the formation of ammonia:

Mg3N2 + 6H2O = 3Mg(OH)2 + 2NH3

(2) The covalent nitrides of nonmetals, and also of aluminum, gallium, indium, and thallium. These nitrides, particularly AlN, BN, and Si3N4, are extremely stable chemically, refractory, and heat-resistant and are dielectrics or semiconductors. Among this group, boron nitride is especially important.

(3) Metal-like nitrides of the transition metals—the largest group of nitrides. Their structure is characterized by the introduction of nitrogen atoms into the crystal lattice of the metal. These nitrides often do not obey the rules of formal valence and are nonstoichiometric compounds (ZrN, Mn4N, and W2N) with broad regions of homogeneity, within which a substantial change in their properties takes place. These nitrides are similar to metals in many aspects. They have high electrical and thermal conductance and are refractory (for example, TiN and HfN melt at 3200° and 3380°C, respectively). They differ from metals in their great hardness, brittleness, and lack of plasticity. Metal-like nitrides are chemically highly stable.

Nitrides are formed on the surface of metals under the action of nitrogen or ammonia at 500°–900°C. The nitride coatings impart increased hardness, durability, and corrosion-resistance to metal parts. Parts made from nitrides are used in high-temperature technology, in the construction of gas turbines, in the power industry, and in space technology. Some metal-like nitrides are superconductors (for example, NbN and MoN are superconducting at 15.6°K and 12°K, respectively). The semiconductor and electrical-insulation properties of nitrides are used in semiconductor technology.

REFERENCE

Samsonov, G. V. Nitridy. Kiev, 1969.

G. V. SAMSONOV

References in periodicals archive ?
Next, nitrogen that does not react with the chrome to form chrome nitride will fill micro-fissures in the steel, effectively locking them in place.
The current hypothesis considers the following sequence for the formation of aluminum nitride. The solubility of aluminum nitride in liquid iron decreases with decreasing temperature.
The coating reportedly also provides corrosion resistance similar to that of stainless steel, while its micro-hardness exceeds that of conventional PVD chromium nitride (CRN) coatings, according to Bell.
Komatsu, "Prototype carbon nitrides similar to the symmetric triangular form of melon," Journal of Materials Chemistry, vol.
To get the maximum benefit from the graphene surface, the team used a precise method for creating thin-films, a process known as atomic layer deposition, to grow two different materials on vertically aligned graphene nanosheets: titanium nitride for their supercapacitor's cathode and iron nitride for the anode.
The tubular structure at the atomic level is what gives nanotubes, whether made of carbon or boron nitride, their incredible strength.
Uranium nitride rips the hydrogen atoms off a carbon atom-no easy task.
At temperature of the experiment 2000 [degrees]C orderly arranged accumulations of secondary nitrides were detected over the whole section of the specimen, where content of nitrogen achieved up to 13 wt.%.
As a result of that, MacQueen noted that Ceradyne has developed silicon nitride to a level where valvetrains of heavy-duty diesel engines, high-pressure common rail fuel pumps and unit fuel injection systems can operate with these ceramic components in conditions where more conventional metal components might fail.
The morphology of boron nitride powder is platelet shaped.
Tantalum and its binary and ternary nitrides are highly refractory materials and are stable to extremely high temperatures; they are non-reactive with copper.