Ceramic Coating Process for NdFeB Magnets With Uniform Corrosion Protection
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Solution Overview
Problem
NdFeB permanent magnets suffer from poor corrosion resistance and high temperature resistance, especially in humid and high-temperature environments, leading to reduced service life and instability due to chemical and electrochemical corrosion, which existing ceramic coatings fail to adequately address.
Innovation Solution
A preparation device and method using high precision spraying equipment to apply a ceramic coating precursor on NdFeB magnets, followed by high-temperature treatment, combining polysilazane with ceramic materials to form a composite ceramic coating that enhances corrosion, high-temperature, and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plasma spraying is used to form Al2O3-T2 composite ceramic coating on NdFeB permanent magnet, then corrosion resistance is improved, but carrier gas cost increases and process complexity increases
Solution Approach 1:
The patent replaces expensive plasma spraying with a low-cost slurry coating method using simple equipment. The coating slurry is applied via brushing or spraying and cured at relatively low temperatures (800-1000°C), eliminating the need for costly plasma generators and specialized carrier gases while achieving comparable corrosion protection.
Solution Approach 2:
The patent changes the coating formation parameters from high-temperature plasma spraying to low-temperature slurry curing. The slurry contains organic vehicles that evaporate and leave ceramic residues forming the coating at 800-1000°C, significantly reducing process complexity and equipment requirements compared to plasma spraying.
2Reliability
If electrostatic spraying of polypropylene, polyethylene and polystyrene with amine curing agents is used to form anticorrosive coating, then corrosion resistance is improved, but high temperature resistance deteriorates because the coating is organic composite not pure ceramic
Solution Approach 1:
The patent changes the chemical composition parameters of the coating by using inorganic ceramic precursors (metal organic compounds or inorganic salt solutions) instead of organic polymers. After curing at 800-1000°C, the organic vehicles evaporate completely, leaving only inorganic ceramic residues that provide both corrosion resistance and high-temperature stability up to 1000°C.
Solution Approach 2:
The patent utilizes phase transition during curing where organic vehicles in the slurry evaporate and decompose at elevated temperatures, transforming the coating from an organic-inorganic composite to a pure inorganic ceramic coating. This phase transition eliminates organic components that limit high-temperature resistance while maintaining corrosion protection.
3Reliability
If conventional coating methods are used to form anticorrosive coating, then corrosion resistance is improved, but coating thickness uniformity deteriorates
Solution Approach 1:
The patent replaces manual brushing or conventional spraying with an automated dip-coating or controlled spray system that ensures uniform coating application. The slurry is applied in a controlled manner and then dried and cured uniformly, producing consistent coating thickness across the magnet surface and improving 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
The method achieves over 90% utilization efficiency of ceramic precursor, ensures uniform coating thickness, and significantly improves the magnets' anti-corrosion, high-temperature, and wear resistance, meeting the requirements for NdFeB magnets.
Implementation Method 1
heating ceramic coating precursor to form organic ceramic coating
Implementation Method 2
combining polysilazane with ceramic materials to form a composite ceramic coating
Implementation Method 3
spray a layer of ceramic coating precursor precisely on the surface of sintered type NdFeB permanent magnet
Implementation Method 4
high precision spraying equipment to apply a ceramic coating precursor
Data Source
AI summary
The disclosure relates to a preparation device and method of forming a ceramic coating on a sintered type NdFeB permanent magnet. The preparation device comprises a holding barrel, a pump body, a spraying system, and a fixture mechanism. The pump body is connected with the holding barrel and the spraying system and the spraying system is located above the fixture mechanism and there is a distance between the spraying system and the fixture mechanism. The fixture mechanism is connected with a recovery bucket through a pipeline, and the recovery bucket is connected with the holding barrel through the pipeline. The spraying system comprises a nozzle, wherein the inlet of the nozzle is connected with the pipeline of the pump body. The fixture mechanism comprises a support plate, an upper recovery trough plate and a lower recovery trough plate, wherein the lower recovery trough plate is located above the support plate.