In general, the disclosure is directed to bulk iron-nitride materials having a polycrystalline microstructure having pores including a plurality of crystallographic grains surrounded by grain boundaries, where at least one crystallographic grain includes an iron-nitride phase including any of a body centered cubic (bcc) structure, a body centered tetragonal (bct), and a martensite structure. The disclosure further describes techniques producing a bulk iron-nitride material having a polycrystalline microstructure, including: melting an iron source to obtain a molten iron source; fast belt casting the molten iron source to obtain a cast iron source; cooling and shaping the cast iron source to obtain a bulk iron-containing material having a body-centered cubic (bcc) structure; annealing the bulk iron-containing material at an austenite transformation temperature and subsequently cooling the bulk iron-containing material; and nitriding the bulk iron-containing material to obtain the bulk iron-nitride material.

Nitride stabilized metal nanoparticles and methods for their manufacture are disclosed. In one embodiment the metal nanoparticles have a continuous and nonporous noble metal shell with a nitride-stabilized non-noble metal core. The nitride-stabilized core provides a stabilizing effect under high oxidizing conditions suppressing the noble metal dissolution during potential cycling.

Bulk iron nitride can be synthesized from iron nitride powder by spark plasma sintering. The iron nitride can be spark plasma sintered at a temperature of less than 600 C. and a pressure of less than 600 MPa, with 400 MPa or less most often being sufficient. High pressure SPS can consolidate dense iron nitrides at a lower temperature to avoid decomposition. The higher pressure and lower temperature of spark discharge sintering avoids decomposition and limits grain growth, enabling enhanced magnetic properties. The method can further comprise synthesis of nanocrystalline iron nitride powders using two-step reactive milling prior to high-pressure spark discharge sintering.

A method may include annealing a material including iron and nitrogen in the presence of an applied magnetic field to form at least one Fe.sub.16N.sub.2 phase domain. The applied magnetic field may have a strength of at least about 0.2 Tesla (T).

The invention relates to a method for producing transition metal compounds having the general composition Me.sub.aC.sub.bN.sub.cH.sub.d where Me=transition metal or transition metal mixture, a=1-4, b=6-9, c=8-14 and d=0-8, wherein a reaction mixture consisting of transition metals and/or transition metal compounds and non-condensed or slightly condensed CNH compounds are subjected to a heat treatment, wherein the content of transition metals and/or transition metal compounds is at least 6 mole percent, preferably 10 to 40 mole percent, relative to the reaction mixture. The invention further relates to transition metal compounds produced in such a manner and to uses thereof.

A process of producing a cathode electrocatalyst for metal-air batteries includes providing a carbon source suspension, a metal source solution, and a nitrogen source solution, subjecting the carbon source suspension and the metal source solution to a low-temperature hydrothermal reaction, subjecting a first precursor-containing product thus formed and the nitrogen source solution to a high-temperature hydrothermal reaction, and subjecting a second precursor thus formed to a heating treatment under a protective atmosphere. A cathode electrocatalyst produced by the process is also disclosed.

A method may include annealing a material including iron and nitrogen in the presence of an applied magnetic field to form at least one Fe.sub.16N.sub.2 phase domain. The applied magnetic field may have a strength of at least about 0.2 Tesla (T).

In general, the disclosure is directed to bulk iron-nitride materials having a polycrystalline microstructure having pores including a plurality of crystallographic grains surrounded by grain boundaries, where at least one crystallographic grain includes an iron-nitride phase including any of a body centered cubic (bcc) structure, a body centered tetragonal (bct), and a martensite structure. The disclosure further describes techniques producing a bulk iron-nitride material having a polycrystalline microstructure, including: melting an iron source to obtain a molten iron source; fast belt casting the molten iron source to obtain a cast iron source; cooling and shaping the cast iron source to obtain a bulk iron-containing material having a body-centered cubic (bcc) structure; annealing the bulk iron-containing material at an austenite transformation temperature and subsequently cooling the bulk iron-containing material; and nitriding the bulk iron-containing material to obtain the bulk iron-nitride material.

In general, the disclosure is directed to bulk iron-nitride materials having a polycrystalline microstructure having pores including a plurality of crystallographic grains surrounded by grain boundaries, where at least one crystallographic grain includes an iron-nitride phase including any of a body centered cubic (bcc) structure, a body centered tetragonal (bct), and a martensite structure. The disclosure further describes techniques producing a bulk iron-nitride material having a polycrystalline microstructure, including: melting an iron source to obtain a molten iron source; fast belt casting the molten iron source to obtain a cast iron source; cooling and shaping the cast iron source to obtain a bulk iron-containing material having a body-centered cubic (bcc) structure; annealing the bulk iron-containing material at an austenite transformation temperature and subsequently cooling the bulk iron-containing material; and nitriding the bulk iron-containing material to obtain the bulk iron-nitride material.

The system for plasma dissociation of hydrocarbons is a plasma-based system for dissociating a feed gas, such as a hydrocarbon gas, and recombining the components thereof into desired materials. The system for plasma dissociation of hydrocarbons includes a chamber having a plasma inlet and a plasma source for projecting a plasma through the plasma inlet into an interior of the chamber. A rotating member is mounted in the interior of the chamber and the rotating member is driven to rotate by a motor or the like such that the plasma impinges on a surface of the rotating member while the rotating member is rotating to form a solid material. The solid material falls from the rotating member under the force of gravity and/or centrifugal force while it is rotating and is collected on an interior floor surface of the chamber.