Neodymium magnets have different grades, like N35, N42, N52, etc.
It can be confusing for you, if you are a beginning buyer for these strongest rare earth magnets.
This post will explain what the different letter and number in a grade’s name mean.
After reading, you’ll be able to pick the right grade for your application.
The grading codes for neodymium magnets start with the letter ‘N’.
- It tells you that the magnetic material is Neodymium.
- So, all the grade codes for neodymium magnets begin with a letter N.
Meanwhile, there is always a number behind the letter N.
- For example, you can find magnets marked N38, N42, N54, etc.
- This number indicates the Maximum Energy Product of the magnet.
- It has a measurement unit “Mega-Gauss Oersteds (MGOe)”.
You can take it as the primary indicator for the strength of a magnet.
- To make it simple: The bigger the number is, the bigger pull force that a magnet can offer for your application.
You can divide the grades of neodymium magnets into different levels based on their strength and performance.
- Please note there is no official or standard way to do this, and we do this based on our experience and understanding.
- We categorize the magnets to help you easily understand the major differences and how to pick the right grade.
Below is one possible way to divide the grades of neodymium magnets into different levels:
Entry level
These are the lowest grades of neodymium magnets, such as N35, N38, and N40.
They have the lowest energy product (MGOe) and the lowest maximum operating temperature (80°C).
They are suitable for applications that do not require very strong or very durable magnets, such as crafts, toys, jewelry, fridge magnets, etc.
They are also the cheapest and most widely available grades of neodymium magnets.
Middle level
These are the intermediate grades of neodymium magnets, such as N42, N45, and N48.
They have higher energy product (MGOe).
They are suitable for applications that require stronger or more stable magnets, such as electric motors, speakers, hard disk drives, magnetic fasteners, etc.
They are more expensive and less common than the entry level grades of neodymium magnets.
High level
These are the highest grades of neodymium magnets, such as N50, N52, and N55.
They have the highest energy product (MGOe).
They are suitable for applications that require the strongest or most durable magnets, such as medical devices, aerospace, military, etc.
They are also the most expensive and rarest grades of neodymium magnets.
Meanwhile, you can also see 1 or 2 additional letters behind the number.
- For example, you can find magnets marked N35M, N42UH.
- These letters indicate the Maximum Operating Temperature (MOT).
If you use a neodymium magnet in a working environment hotter than its rated MOT:
- It will lose its magnetism proportionally forever.
- So, it’d better to buy neodymium magnets with sufficient temperature resistance.
Currently, N55 is the highest grade for NdFeB magnets.
- But, many magnet manufacturers can only achieve the N52 performance level.
Usually, for a substrate of N35 NdFeB strong magnet measures F64 x 54 x 35 mm in dimension:
- When it comes to magnetization, it’s crucial that the magnetization direction should not exceed the length and width of the substrate block.
- If it does, the magnetic molecules won’t align properly, resulting in a non-magnetic magnet.
This is especially challenging in the production of high-performance N52 NdFeB magnets.
The technical complexities and sintering process are more demanding compared to producing N35 materials.