Rare earth neodymium iron boron is also known as neodymium magnet. In 1982, Sumitomo special metal Mr. satakawa discovered neodymium magnet, which is mainly composed of iron Fe (about 65%), boron B (about 1%) and rare earth RE. The main rare earth element is neodymium (nd). Since the end of 1980s, China began to produce Nd-Fe-B materials in batches, and it has been growing rapidly year by year. In 2001, the output accounted for 52.9% of the world output, and in 2008, the output accounted for 78.6% of the world output. Rare earth permanent magnetic materials have been widely used in many industries due to their unique advantages of high magnetic energy product, high coercivity and high remanence.
The advantages of NdFeB are high cost performance and good mechanical properties; The disadvantages are low working temperature, poor temperature characteristics, easy to powdering and corrosion. In order to meet the requirements of practical application, it must be improved by adjusting the chemical composition and using surface treatment methods.
Neodymium iron boron is a kind of fine alloy. There are tiny pores and voids in it. It is easy to absorb oxygen in the atmosphere, which oxidizes rare earth elements and destroys alloy components. Long time causes the magnetic property attenuation until vanishes, affects the overall service life and performance. Therefore, strict anti-corrosion treatment must be carried out before use.
The surface of NdFeB is rough and porous; Strong chemical activity leads to poor adhesion between the coating and NdFeB substrate, which brings potential defects to the electroplating products and leads to blistering and peeling of the coating, which has always plagued the NdFeB electroplating industry,
Specifically, there are the following points:
- neodymium iron boron will rust after oil and water cleaning, forming rust film;
- NdFeB is easy to oxidize and absorb moisture. In order to reduce the loss of NdFeB, the pickling time should be shortened;
- The main production process of NdFeB is sintering. Pickling process has a great influence on the adhesion of sintered NdFeB Ni coating. The results show that the alkaline passivation treatment has better effect on oil removal, water washing, acid washing, water washing, passivation and water washing, and the time and cost of acid washing are larger;
- After the pretreatment of electroplating or electroless plating, if bubbles appear after coating, the holes should be closed.
Jiafei neodymium iron boron automatic electroplating production line develops neodymium iron boron electroplating from simple surface protection technology to a comprehensive technology integrating materials, electroplating process, process design and equipment manufacturing. High hole double roller filter is used to reduce the defect rate of workpiece and improve the ultrasonic efficiency. After multi-channel high-energy ultrasonic precision cleaning, it can completely remove oil, acid and alkali and other substances in neodymium iron boron material micropores, and improve the adhesion of the coating. For neodymium iron boron material with strong chemical activity and corrosion resistance, the intelligent detection system of conductive liquid is developed. On the one hand, it can keep the electrolyte concentration constant, on the other hand, it can monitor the change of current density at any time, In order to ensure uniform coating, full-automatic solution delivery, prevent substrate oxidation, reduce the hydrogen absorption effect of NdFeB microporous surface, fast plating speed, good coating adhesion.
Post time: Jul-07-2021