Examples of Neodymium Magnets
Examples of Neodymium Magnets
NdFeB magnets are labeled with a letter or two which indicates the magnetic strength of the grade. The grades range from N24 to with N52 being the strongest magnetic strength that is available.
Magnets are classified as "soft" or hard ferromagnetic materials. The soft ones such as iron that has been annealed can be easily magnetized and then demagnetized. The harder ferromagnetic materials like alnico and ferrite resist magnetization.
NdFeB
The Nd2Fe14B is a compound made from the rare earth element called neodymium. It has a tetragonal crystalline structure with a high saturation magnetic field and an anisotropy that is uniaxial. Other elements are able to be added to alloys to create different magnetic properties. These other metals include dysprosium, praseodymium, with minor amounts of aluminum (Al) Cobalt (Co), and Boron (B) in the neodymium magnetic material.
In its atomic structure, neodymium has four unpaired electrons which is higher than iron's (3 unpaired). It can therefore have massive magnetic dipole moments. This property gives neodymium magnets their incredible magnetic power. It is 18 times stronger than normal ferrite and 12 times stronger than Samarium Cobalt.
If the material is exposed to water, it will quickly corrode, a condition called "ferrolytic corrosion". The corrosion can cause an irreparable structural change - either the magnet is smashed into a powder composed of tiny magnetic particles or spalling of the surface layer. NdFeB Magnets need to be shielded or encased with a hermetic coating to avoid corrosion and preserve their magnetic properties.
NdPr
Rare earth elements like Neodymium, Praseodymium or NdPr are to the green revolution what Thailand and Ibiza were to travellers before becoming a secret for everyone. NdPr is an essential element in the high-tech sector, where its ferromagnetism makes for strong and lightweight magnets. These magnets are vital to making sleek designs in batteries electric wind turbines and vehicles, which are changing our lives. They are also bringing us closer to a sustainable economy.
These technologies make use of NdFeB magnetic materials that require a huge quantity of raw materials. This includes the rare earths with heavy weights, such as praseodymium and neodymium. These rare earths, which are in short supply due to the aggressive growth goals of global emobility as well as green technology manufacturers, are also in short supply. China is winning this race which could lead to a radical price change in the NdPr industry.
To meet these increasing demand goals, Chinese producers are ramping up their capacity rapidly. And that's creating pressure on the world's EV manufacturers to sign long-term agreements with their Chinese suppliers to ensure constant supplies of magnets. Adamas predicts that NdPr oxide will reach 200 dollars per kilogram in 2030. This is a significant increase over the current prices that are driven mainly by supply-side bottlenecks and projections of rising market deficits in NdPr oxide globally.
Samarium Cobalt
Oft referred to as SmCo, Samarium Cobalt magnets are among the strongest permanent magnetic materials available. Although they aren't as strong as NdFeB, they can operate at high temperatures, possess higher temperature coefficients and significantly higher corrosion resistance. They also provide outstanding resistance to demagnetization.
SmCo can be produced in two ways: by sintering and isostatic pressing. During the sintering procedure super-fine samarium gets pressed to a solid using rubber dies placed over the magnet in order to create equally on all sides. The result is a dense magnet with better magnetic properties, but also smaller in size. The isostatic process produces a magnet with less magnetic properties and larger in size, however, it is more reliable and stable than the sintering process.
SmCo is among the most difficult rare earth magnets that can be made and requires the use of specialized tools. SmCo is brittle and requires diamond tools to avoid damage. Additionally, samarium-cobalt is extremely reactive with oxygen in the air. This makes it necessary to have an atmosphere of protection when processing and sintering and to add a variety alloying elements to the melt. SmCo is generally thought to be the most suitable choice for applications that require a high magnet strength at extreme temperatures, such as sensors, motors, and generators.
Iron Nitride
Iron Nitride is a magnetizing compound that is used in magnets, electric motors and magnetic resonance imaging. It is created by heating iron to high temperatures, and then decomposing into its constituent elements, which are iron and nitrogen. It is possible to regulate the structure of FeN by adding dopant elements like cobalt (Co) and titanium (Ti) and copper (Cu) and zinc (Zn). Mossbauer spectroscopy has proven to be a useful instrument to study different site characterizations in FeN including those of compounds and phases.
The energy maximum of NdFeB is described in Mega Gauss Oersteds. However, this number does not tell us much about the performance of the magnet in a specific application. To predict the performance of a magnetic device, it is necessary to take into account other magnetic characteristics. These include remanence and coercivity.
The process of making Neodymium magnetics begins with a liquid alloy made of NdFeB and other rare earth metals which is melted and poured onto the rotating cold disk. The molten material will solidify into a ribbon in a short time. The material is then chopped into 200 mp pieces which are then joined to polyamides. Injection molding can be used to create magnets. The magnets that result are graded by the letters of their NdFeB grade classification, with higher grades offering greater magnetic energy.