Cold storage material particle, cold storage device, refrigerator, cryopump, superconducting magnet, nuclear magnetic resonance imaging apparatus, nuclear magnetic resonance apparatus, magnetic field application type single crystal pulling apparatus, and method for producing cold storage material particle
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Solution Overview
Problem
Cold storage material particles in cryogenic refrigerators are prone to breakage and pulverization due to pressure vibrations and thermal shocks, leading to reduced refrigeration capacity and reliability.
Innovation Solution
Development of cold storage material particles comprising a rare earth element, silver, or copper, with an additive metal element that forms multivalent metal ions, optimized for high volume specific heat, mechanical strength, and heat transfer, using a production method involving alginic acid aqueous solutions and gelling processes to enhance sintering and thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cold storage material particles are used in cryogenic refrigerators, then refrigeration capacity is achieved through heat exchange with helium gas, but the particles break and pulverize due to pressure vibrations and thermal shocks, reducing refrigeration capacity and reliability
Solution Approach 1:
The invention uses composite cold storage material particles comprising a core shell structure where a rare earth element compound core is coated with a metal matrix. This composite structure combines the high volume specific heat of rare earth compounds with the high mechanical strength and thermal conductivity of metals, resolving the contradiction between reliability and mechanical strength.
Solution Approach 2:
The invention changes the physical and chemical parameters of the cold storage material by selecting specific rare earth elements (Gd, Tb, Dy) and metals (Al, Cu, Ag) with optimized atomic concentrations. The metal content is controlled at 1-50 at% to balance mechanical strength enhancement while maintaining sufficient volumetric specific heat for refrigeration performance.
2Use of energy by moving object
If cold storage material particles are used in cryogenic refrigerators, then heat exchange with helium gas provides refrigeration capacity, but thermal conductivity is insufficient leading to reduced heat transfer efficiency
Solution Approach 1:
The metal coating layer in the composite particle structure provides high thermal conductivity pathways for heat exchange between the helium gas and the rare earth element core. This resolves the contradiction by using the metal's superior thermal conductivity to enhance overall heat transfer while the rare earth core maintains high volumetric specific heat.
3Quantity of substance
If high-volume specific heat materials are used to achieve high refrigeration capacity, then mechanical strength is insufficient causing particle breakage under pressure vibrations
Solution Approach 1:
The composite structure combines rare earth element compounds (high volumetric specific heat) with metal matrices (high mechanical strength). The metal coating protects the brittle rare earth core from mechanical damage while maintaining the high heat storage capacity needed for cryogenic refrigeration.
Solution Approach 2:
The invention applies different material properties to different parts of the particle: the rare earth element core provides high volumetric specific heat for refrigeration capacity, while the metal coating provides mechanical strength and thermal conductivity. This local differentiation of material quality resolves the contradiction between volumetric specific heat and mechanical strength.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The particles exhibit improved mechanical strength, thermal conductivity, and heat transfer, maintaining high refrigeration capacity and long-term reliability by optimizing the atomic concentration and distribution of additive metal elements, thereby reducing manufacturing costs and enhancing performance.
Implementation Method 1
optimized for high volume specific heat, mechanical strength, and heat transfer, using a production method involving alginic acid aqueous solutions and gelling processes to enhance sintering and thermal conductivity
Implementation Method 2
cold is generated by performing heat exchange between the cold storage material particles and helium gas passing through the cold storage device
Implementation Method 3
using a production method involving alginic acid aqueous solutions and gelling processes to enhance sintering and thermal conductivity
Data Source
AI summary
A cold storage material particle of an embodiment includes at least one first element selected from the group consisting of a rare earth element, silver (Ag), and copper (Cu) and a second element that is different from the first element and forms a multivalent metal ion in an aqueous solution, in which an atomic concentration of the second element is 0.001 atomic % or more and 60 atomic % or less, and a maximum value of volume specific heat at a temperature of 20K or less is 0.3 J/cm3·K or more.