Invention Grant
- Patent Title: Method for improving corrosion resistance of neodymium-iron-boron materials by low-temperature oxidation and/or nitridation treatment
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Application No.: US17711551Application Date: 2022-04-01
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Publication No.: US12112884B2Publication Date: 2024-10-08
- Inventor: Mi Yan , Jiaying Jin , Wang Chen , Chen Wu
- Applicant: ZHEJIANG UNIVERSITY
- Applicant Address: CN Hangzhou
- Assignee: ZHEJIANG UNIVERSITY
- Current Assignee: ZHEJIANG UNIVERSITY
- Current Assignee Address: CN Hangzhou
- Priority: CN 2210199160.8 2022.03.02
- Main IPC: H01F41/02
- IPC: H01F41/02 ; C21D8/12 ; H01F1/057

Abstract:
A method for improving the corrosion resistance of NdFeB materials is provided. The method includes in-situ growing a layer of oxide, nitride, or oxynitride on the surface of NdFeB magnet correspondingly by performing at least one of an oxidation treatment and a nitridation treatment at low temperature in a range of 200˜400° C., thereby significantly improving the corrosion resistance of the magnet. The method is simple to operate, low-cost, green, safe, and efficient. Depending on the parameters of the low-temperature oxidation and/or nitridation treatment, the thickness of the oxide, nitride, or oxynitride layer is adjustable from 10 nm to 100 μm, which can improve the corrosion resistance of the magnet while maintaining excellent magnetic properties. Moreover, the thin surface layer is in-situ grown on the NdFeB substrate, which is strong and stable over a long service period and can be applied for mass production.
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