Multicomponent Magnet Assemblies With Local High-Coercivity Regions

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Solution Overview

Problem

The production of multicomponent permanent magnets with varying magnetic properties is complex and costly due to the need for multiple processing steps and high consumption of expensive heavy rare earth elements, which are not efficiently distributed within the magnets, leading to issues with coercivity loss at high temperatures and in extreme magnetic stray fields.

Innovation Solution

A method of manufacturing multicomponent permanent magnets by independently producing and connecting magnet components with different coercivity levels, using a higher amount of coercivity-enhancing elements like heavy rare earth elements only where needed, and ensuring an electrically conductive connection to maintain reproducible magnetic properties and reduce production costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If heavy rare earth elements are added to increase coercivity, then the magnet can withstand high temperatures and extreme magnetic fields, but the cost increases and remanence decreases

Engineering Contradiction:
Improvecoercivity at high temperatureVSAvoidcost and remanence
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies local quality by creating a multicomponent magnet structure where different regions have different compositions and magnetic properties. Specifically, a first permanent magnet component has a first composition with lower heavy rare earth content (higher remanence), while a second permanent magnet component has a second composition with higher heavy rare earth content (higher coercivity). This allows high coercivity to be provided only where needed to withstand extreme magnetic fields, while other regions maintain higher remanence, thus resolving the contradiction between reliability and material quantity/cost.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If multicomponent magnets are produced by combined sintering of different magnet powder grades, then high-performing magnets with reduced HRE amounts are achieved, but the production process becomes complicated and expensive

Engineering Contradiction:
ImproveHRE consumptionVSAvoidproduction complexity
Core Design Contradiction:
Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent applies segmentation by dividing the multicomponent magnet into separately produced permanent magnet components. Each component is produced independently with its specific composition and magnetic properties, then the components are assembled together. This segmentation approach simplifies manufacturing compared to combined sintering, as each component can be produced using standard processes optimized for its specific grade, avoiding the complexity of simultaneously sintering multiple powder grades together.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If different grades of permanent magnet material are produced in the same process, then multicomponent structure is achieved, but it is difficult to optimize processing conditions for each grade

Engineering Contradiction:
Improvedifferent magnetic propertiesVSAvoidprocessing condition optimization
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

By segmenting the magnet production into separate components, each component can be processed independently under optimized conditions for its specific material grade. The first permanent magnet component and second permanent magnet component are produced separately, allowing full optimization of sintering temperature, holding time, and other processing parameters for each composition without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by producing and characterizing each permanent magnet component separately before assembly. This allows the magnetic properties of each component to be optimized and verified independently, ensuring that each component meets its specific performance requirements before being combined into the final multicomponent magnet structure.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3729475B1Multicomponent magnet assemblies for electrical machines
Publication Date: 2023.09.06 ABB (SCHWEIZ) AG
  • EP3729475B1 patent drawingFigure 1~2
  • EP3729475B1 patent drawingFigure 3~4A
  • EP3729475B1 patent drawingFigure 4B~4C

AI summary

A method for manufacturing a multicomponent permanent magnet, and a multicomponent permanent magnet are proposed. The multicomponent permanent magnet has a first permanent magnet having a R-T-B-composition, wherein R is at least one selected from the group consisting of Y, Ce, La, Pr, Nd, Sm, Eu and Gd and T is one or more transition metal elements including Fe; and a second permanent magnet having a R-T-B-composition, wherein R is at least one selected from the group consisting of Y, Ce, La, Pr, Nd, Sm, Eu and Gd and T is one or more transition metal elements including Fe, the second magnet comprising at least one of a heavy rare earth element (HRE) and an increased amount of Ce and/or Co, the second magnet having different magnetic properties, in particular a higher coercivity, than the first magnet. The first magnet and the second magnet are connected mechanically, whereby the connection is electrically conductive with an adjusted electrical resistivity.