Process for producing a magnetocaloric composite material and a corresponding heat exchanger
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Solution Overview
Problem
Conventional methods for manufacturing magnetocaloric composite materials for heat exchangers are costly, energy-intensive, and often use toxic components, with inadequate coating of particles and mechanical stability, leading to fatigue failure and inefficient heat transfer.
Innovation Solution
A method involving pretreatment of magnetocaloric particles followed by immersion in a nickel bath for chemical metal coating, utilizing substances like nickel(II) chloride, ammonium chloride, and sodium citrate, to form a mechanically and chemically stable composite material through electroless nickel plating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If low-melting metal alloys are used to bond magnetocaloric particles, then the particles can be joined together, but the mechanical stability and chemical resistance are insufficient leading to fatigue failure
Solution Approach 1:
The invention changes the bonding mechanism from mechanical bonding using low-melting metal alloys to chemical bonding through electroless nickel plating. The nickel coating forms a chemically stable layer that bonds particles together through metallurgical bonding, providing superior mechanical strength and fatigue resistance compared to low-melting alloy bonding.
Solution Approach 2:
The invention creates a composite structure where magnetocaloric particles are coated with nickel and bonded together. This composite approach combines the magnetic properties of the magnetocaloric material with the mechanical strength and chemical stability of nickel, achieving both functional and structural requirements.
2Reliability
If conventional metal alloy bonding is used, then particles can be joined, but complete coating of all particles cannot be guaranteed and toxic components are used
Solution Approach 1:
The electroless nickel plating process is a self-service chemical deposition method where nickel ions are reduced and deposited onto the particle surfaces through a chemical reaction. The process automatically coats all particles uniformly without requiring manual application or complex equipment, ensuring complete coverage while avoiding toxic bonding agents.
Solution Approach 2:
The invention replaces the mechanical and thermal process of melting and pouring metal alloys with a chemical deposition process. The electroless plating uses chemical reactions to deposit nickel onto particles at lower temperatures, eliminating the need for high-temperature melting and toxic low-melting alloys while ensuring uniform complete coating.
3Strength
If molten metal alloy is used to bond particles, then particles can be joined, but significant energy consumption is required to melt the metallic composite material
Solution Approach 1:
The invention changes the bonding process from high-temperature melting to low-temperature chemical deposition. The electroless nickel plating occurs at temperatures below 100°C, dramatically reducing energy consumption compared to melting metal alloys while still achieving strong metallurgical bonding between particles.
4Ease of manufacture
If polymer matrix is used to bond magnetocaloric particles, then particles can be joined, but heat transfer to the transport medium is insufficient
Solution Approach 1:
The invention creates a composite structure where magnetocaloric particles are coated with nickel and bonded together through metallurgical bonding. This nickel-nickel metallic composite provides superior thermal conductivity compared to polymer matrices, enabling efficient heat transfer to the transport medium while maintaining manufacturing simplicity through the electroless plating process.
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 method produces a cost-effective, non-toxic, and highly stable magnetocaloric composite material with enhanced heat transfer properties, suitable for various applications, including magnetic refrigeration units, by ensuring complete particle coating and improved mechanical stability.
Implementation Method 1
immersing the large number of particles present in the shaped body in a bath, in particular a nickel bath, in order to join the particles in the bath together to form a composite material by chemical metal coating
Implementation Method 2
chemical precipitation of nickel is used, as a result of which mechanically and chemically stable heat exchangers can be manufactured
Data Source
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AI summary
A process for producing a magnetocaloric composite material for a heat exchanger is disclosed. The process comprises the following steps: providing (S110) a multitude of particles (110) of a magnetocaloric material in a shaped body (200) and immersing the multitude of particles (110) present in the shaped body (200) into a bath in order to coat the particles by a chemical reaction and bond them to one another.