MgB2 Superconducting Wire Joint via Boron Powder Compaction
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Solution Overview
Problem
The existing methods for connecting MgB2 superconducting wires result in porous joints with low current-carrying capacity, limiting the efficiency and critical magnetic field strength of superconducting systems.
Innovation Solution
A method involving the compaction of bulk boron powder with exposed wire filaments, followed by infiltration with molten magnesium to form a dense MgB2 matrix, maintaining porosity and enhancing the joint's current-carrying capacity by creating well-defined superconducting paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MgB2 filaments are overlapped and heated with boron powder and magnesium powder to form MgB2 connection, then superconducting connection is achieved, but the generated MgB2 is highly porous and current-carrying capacity is relatively small
Solution Approach 1:
The invention applies preliminary action by pre-forming a compressed element from boron powder before infiltration. This compressed element serves as a pre-prepared substrate that maintains structural integrity and controlled porosity, allowing subsequent magnesium infiltration to occur in a controlled manner. The pre-compression step ensures that the final MgB2 joint achieves high density and low porosity, resolving the contradiction between reliability and manufacturing precision.
Solution Approach 2:
The compressed element acts as an intermediary between the magnesium source and the final MgB2 joint structure. By introducing this intermediate compressed boron powder element, the invention enables controlled transformation from porous powder mixture to dense MgB2 joint, achieving both high current-carrying capacity and low porosity simultaneously.
2Ease of manufacture
If bulk boron powder is compressed with wire filaments to form compressed element, then porosity is maintained for infiltration, but density of the joint may be reduced
Solution Approach 1:
The invention applies parameter changes by controlling the compression parameters of the boron powder to achieve optimal porosity. The compression is performed with specific pressure and density parameters that maintain sufficient porosity for magnesium infiltration while ensuring high enough initial density to achieve dense final joint after infiltration. This parameter optimization resolves the contradiction between ease of manufacture and manufacturing precision.
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
This method produces high-density MgB2 joints with improved current-carrying capacity and stability, facilitating efficient and cost-effective connections between MgB2 superconducting wires without increasing porosity, thus enhancing the overall performance of superconducting systems.
Implementation Method 1
the compressed element is infiltrated by molten magnesium starting from the surface of the compressed element
Implementation Method 2
the bulk powder is compacted together with the projecting exposed end regions of the filaments to form a compressed element, wherein the compressed element is infiltrated by molten magnesium starting from the surface of the compressed element
Implementation Method 3
boron and magnesium react to form MgB2
Data Source
AI summary
A method for superconductingly connecting two or more wires (1, 2), each comprising at least one filament (3a-3d) that contains MgB2 or a mixture of Mg and B, wherein a superconducting connection is realized through exposed end regions (4a) of the filaments (3a-3d) via an MgB2 matrix, is characterized in that a bulk boron powder (4) is provided into which the exposed end regions (4a) of the filaments (3a-3d) of the wires (1, 2) project, the boron of the bulk boron powder (4) being present in amorphous modification. The bulk powder (4) is then compacted together with the projecting exposed end regions (4a) of the filaments (3a, 3b) to form a compressed element (8) and the compressed element (8) is infiltrated with molten magnesium (10) from the surface (13) of the compressed element (8). The method improves the quality, in particular, the current-carrying capacity and the critical magnetic field strength of a superconducting connection of MgB2 superconducting wires.