52 results about "Magnetic phase transition" patented technology

The invention provides a MnCoGe-based magnetic material with a giant piezocaloric effect as well as a preparation method and application thereof. A chemical general formula of the MnCoGe-based magnetic material is MnCoGe1-xInx, wherein x is more than 0 and less than or equal to 0.03, and the MnCoGe-based magnetic material has a Ni2In type hexagonal structure. The MnCoGe-based magnetic material has the characteristic that martensitic structural phase transition and magnetic phase transition are coupled, and coupling is carried out at the temperature close to room temperature. The MnCoGe-based magnetic material shows an adverse piezocaloric effect under the action of pressure, the amplitude of entropy change under the action of pressure of 3kbar and at the temperature close to room temperature is at least 50J / (Kg.K). Along with change of In content, the magnetic structure coupling temperature Tmstru of the material is adjustable at a wide temperature region close to room temperature, so that the giant piezocaloric effect appears in the wide temperature region close to room temperature. The MnCoGe-based magnetic material has the advantages of simple preparation method, green and environmental-friendly raw materials, high efficiency and energy conservation.

The invention belongs to the field of magnetic refrigeration, and specifically relates to a cobalt-manganese-tin-based alloy material and a preparation method thereof. The molecular formula of the cobalt-manganese-tin-based alloy material is Co 1‑x mn 1+x Sn, where x=0.02‑0.10, its structure is hexagonal. The alloy material overcomes the shortcomings of the small magnetic entropy change half-peak width and large thermal hysteresis of the first-order magnetic phase transition. Its phase transition behavior is a second-order magnetic phase transition, which has a large magnetocaloric effect and avoids Large thermal hysteresis effect. Cobalt-manganese-tin alloy has low cost and broad application prospects, and can be applied to many important fields of the national economy involving refrigeration and cryogenic technology.

The invention discloses a magnetic phase-change microcapsule for performing thermal protection on a normal structure in thermal physical therapy. The magnetic phase-change microcapsule is a spherical microcapsule which is composed of a phase-change material (1), magnetic particles (2) and a liposome shell (3), and the mean diameter thereof is 1nm-1mm. In the invention, the phase-change material (1) is solid-liquid or / and liquid-solid phase-change material with high phase change heat and the phase change temperature at -10-0 DEG C or 38-100 DEG C according to different thermal physical therapeutic processes such as thermal therapy, cold therapy, cryosurgery or cold-heat alternating therapy and the like; the magnetic particles (2) are magnetic micro / nano-particles or magnetotactic bacteria;and a liposome is taken as a capsule carrier for lowering toxicity of the material and protecting an encapsulated material. The invention provides a safe and effective thermal protection material with novel concept. In the invention, the magnetic phase-change microcapsule can be gathered into a target organ with blood circulation under the action of an applied magnetic field; phase-change latent heat and low thermal conductivity of the phase-change material are adopted to carry out thermal protection on the normal structure; and the material is widely applied to thermal physical therapy, and the application method thereof is simple, feasible and reliable.

The invention relates to the technical field of high-entropy alloys and discloses a six-element high-entropy alloy with a first-order magnetic phase transition and a preparation method thereof. The six-element high-entropy alloy with the first-order magnetic phase transition has a general formula structure of MgaMnbFecCodNieGdf and is obtained by electrochemical reduction deposition, wherein an electrolyte in the electrochemical reduction deposition comprises the following components: dimethyl sulfoxide, tetraethylammonium hexafluorophosphate, vitamin C, GdCl3, FeCl2, CoCl2, NiCl2, MnCl2 and MgCl2. The prepared alloy is an amorphous alloy, the magnetic transition of the prepared alloy is the magnetic transition caused by strong electron correlation without being restrained by the crystal form transformation of a material, and therefore, the high-entropy alloy has the advantages of large temperature range of magnetic phase transition, controllable critical transition temperature and reversibility.

The present invention involves the technology field of magnetic phase transformation materials, and the invention has disclosed an MN absent -position MN replaced by BI 2 SB consequences and their preparation methods and applications, MN replaced by BI 2 The chemical formula of the SB conformity is: mn 2‑y SB 1‑x BI x Among them, Y is the absence of MN atoms, X represents the replacement amount of BI on SB, 0 <y <1, 0 <x ≤0.4;Then use the method of doping or element replacement to prepare the MN default MN replaced by BI 2 SB conformity alloy, regulates the first -level magnetic phase change and obtains a rich magnetic function in the alloy. 2 The SB consecutive is widely used in multiple fields such as magnetic refrigeration, magnetic storage, magnetic sensing, energy capture and energy exchange, and the preparation methods are simple and convenient, less energy consumption, low preparation costs, and suitable for industrial production.

The invention relates to a preparation method of a high-coercivity Fe-Pt alloy, which belongs to the technical field of new materials. Fe-Pt-B alloy strips with low Pt content were prepared by arc or induction melting and single-roller stripping as precursor alloys, and then prepared by dealloying the precursor alloy strips in a weakly acidic environment by electrochemical process The nanoporous Fe-Pt alloy with uniform pore size is then subjected to vacuum annealing treatment, and the hard magnetic L10-FePt phase is obtained through phase transformation, so that the alloy has high coercive force. The coercive force of the Fe-Pt alloy prepared by the method provided by the invention exceeds 6.12kOe under an external magnetic field of 18kOe, which is much higher than that of the Fe-Pt alloy prepared by the traditional method. The invention provides a new method for the preparation of the permanent magnetic material, and also opens up a new application field for the nanoporous metal material.