University of Minnesota

University System of Maryland

Niron Magnetics, Inc.

Other

Yiming Wu

Jian-Ping Wang

Bin Ma

Jinming Liu

Yunho Hwang

Ichiro Takeuchi

Francis Johnson

Yanfeng Jiang

John M Larson

Jun Cui

Reinhard Radermacher

Richard W Greger

Jan Muehlbauer

K Reinhard Radermacher

Jiazhen Ling

Manfred R Wuttig

Xiaowei Zhang

Fan Zhang

Guannan Guo

Kathryn Sara Damien

Suxin Qian

Delin Zhang

Md Aminul Mehedi

YanFeng Jiang

L Anderson Blackburn

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.

Iron-nitride magnet by nitriding a porous structure

Iron nitride nanoparticles and magnet materials made from iron nitride nanoparticles are described. The iron nitride nanoparticles have a core and a shell morphology. The shell is configured to provide a means to nitride the core. The magnetic materials are characterized as having an Msat greater than about 160 emu/g and a coercivity greater than about 700 Oe.

Coercivity-enhanced iron nitride nanoparticles with high saturation magnetization

An example composition may include a plurality of grains including an iron nitride phase. The plurality of grains may have an average grain size between about 10 nm and about 200 nm. An example technique may include treating a composition including a plurality of grains including an iron-based phase to adjust an average grain size of the plurality of grains to between about 20 nm and about 100 nm. The example technique may include nitriding the plurality of grains to form or grow an iron nitride phase.

Iron nitride compositions

Example nanoparticles may include an iron-based core, and a shell. The shell may include a non-magnetic, anti-ferromagnetic, or ferrimagnetic material. Example alloy compositions may include an iron-based grain, and a grain boundary. The grain boundary may include a non-magnetic, anti-ferromagnetic, or ferrimagnetic material. Example techniques for forming iron-based core-shell nanoparticles may include depositing a shell on an iron-based core. The depositing may include immersing the iron-based core in a salt composition for a predetermined period of time. The depositing may include milling the iron-based core with a salt composition for a predetermined period of time. Example techniques for treating a composition comprising core-shell nanoparticles may include nitriding the composition.

Iron-based nanoparticles and grains

Disclosed herein is a permanent magnet comprising: a plurality of aligned iron nitride nanoparticles wherein the iron nitride nanoparticles include &#x3b1;&#x2033;-FeNphase domains; wherein a ratio of integrated intensities of an &#x3b1;&#x2033;-FeN(004) x-ray diffraction peak to an &#x3b1;&#x2033;-&#x3b1;&#x2033;-FeN(202) x-ray diffraction peak for the aligned iron nitride nanoparticles is greater than at least 7%, wherein the diffraction vector is parallel to alignment direction, and wherein the iron nitride nanoparticles exhibit a squareness measured parallel to the alignment direction that is greater than a squareness measured perpendicular to the alignment direction.

Anisotropic iron nitride permanent magnets

A system for heating/cooling includes a plurality of thermoelastic modules. Each of the modules includes one or more structures formed of shape memory alloy, which converts from austenite to martensite upon application of a first stress and release latent heat from the conversion. During a first part of a heating/cooling cycle, a first module is stressed to cause conversion. The latent heat released from the first module is rejected to a heat sink while a second unstressed module absorbs heat from a heat source. During a second part of the heating/cooling cycle, the first and second modules are connected together to transfer heat therebetween for heat recovery. The cycle can be repeated indefinitely with the first and second modules alternating roles. Structures of the thermoelastic cooling material and specific applications thereof are also disclosed.

Solid-state heating or cooling systems, devices, and methods

A cooling system based on thermoelastic effect is provided. The system comprises a heat sink, a refrigerated space and a regenerator coupled to the refrigerated space and to the heat sink to pump heat from the refrigerated space to the heat sink. The regenerator comprises solid thermoelastic refrigerant materials capable of absorbing or releasing heat.

Thermoelastic cooling

Growing community of inventors

Shoreview, MN, United States of America

Yiming Wu