Composite surface protecting method for neodymium-iron-boron magnet

Abstract

The invention discloses a composite surface protecting method for a neodymium-iron-boron magnet, comprising the following steps of: pretreating a neodymium-iron-boron magnet, electroplating or phosphating the pretreated neodymium-iron-boron magnet, spraying a corrosion-resistant coating on the surface of the electroplated neodymium-iron-boron magnet, pre-curing the sprayed neodymium-iron-boron magnet, curing the pre-cured neodymium-iron-boron magnet and performing vapour phase deposition on the cured neodymium-iron-boron magnet. The composite surface protecting method for the neodymium-iron-boron magnet has the following advantages that: the combining stability between the plating and the neodymium-iron-boron magnet and the corrosion-resistant property of the plating are improved by meansof the corrosion-resistant coating; the electroplating treatment and the spraying treatment are further enhanced by the vapour phase deposition; meanwhile, a circular hole structure of the neodymium-iron-boron magnet is further plated so that the integrated plating on the surface of the neodymium-iron-boron magnet is uniform; and the endurance time of the neutral salt spray test of the compoundedneodymium-iron-boron magnet can reach more than 300 hours.

Description

technical field [0001] The invention relates to a protection method for NdFeB magnets, in particular to a surface composite protection method for NdFeB magnets. Background technique [0002] NdFeB magnets have excellent magnetic properties and high cost performance, and are widely used in technical fields such as electronics, motors and communications; however, NdFeB magnets are very active and are easily corroded, resulting in rust, pulverization or Problems such as loss of magnetism greatly limit the service life and application fields of NdFeB magnets; at present, the electroplating treatment on the surface of NdFeB magnets is mainly used to improve its anti-corrosion performance, although the electroplating layer isolates NdFeB magnets to a certain extent. The contact between the boron magnet and the external environment improves the corrosion resistance of the NdFeB magnet. However, due to the limitations of the electroplating process, there are more or less pores in th...

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Problems solved by technology

[0002] NdFeB magnets have excellent magnetic properties and high cost performance, and are widely used in technical fields such as electronics, motors and communications; however, NdFeB magnets are very active and are easily corroded, resulting in rust, pulverization or Problems such as loss of magnetism greatly limit the service life and application fields of NdFeB magnets; at present, the electroplating treatment on the surface of NdFeB magnets is mainly used to improve its anti-corrosion performance, although the electroplating layer isolates NdFeB magnets to a certain extent. The contact between the boron magnet and the external environment improves the corrosion resistance of the NdFeB magnet. However, due to the limitations of the electroplating process, there are more or less pores in the electroplating coating, and the external environment can contact the NdFeB magnet through these pores. , so as to corrode NdFeB magnets; especially when electroplating NdFeB magnets with a large depth-to-diameter ratio (depth-to-diameter ratio ≥ 1) with a circular hole (inner hole diameter ≤ 10mm) structure, the roundness of the NdFeB magnet It is difficult to form a uniform electroplating coating in the depth of the hole, and the coating on the surface of the deep hole is very thin, which will become a breakthrough for the corrosion of the NdFeB magnet, shortening the corrosion resistance protection period of the NdFeB magnet surface coating; after electroplating treatment NdFeB magnets with a round hole structure with a large depth-to-diameter ratio can generally only withstand the neutral salt spray test for about 36 hours, which cannot meet the needs of power motor magnets for corrosion resistance and motor operation reliability