When buying magnets, we generally determine the material first, but what seems to be a very simple choice, but to take into account all factors, will soon become complicated. rare earth neodymium magnets and ceramic ferrite magnet as the two most common magnets, many customers in the custom magnet, will ask us: my custom magnet should use which material magnet?
So what are the factors that we need to take into account? Such as performance, magnetism, appearance, cost, efficiency, system weight, system size, form factor, aesthetics, lead time and other considerations. Today, we will analyze the difference between ferrite and neodymium magnets from several aspects.
Comparison of the appearance of rare earth neodymium magnets and ceramic ferrites
What is neodymium magnet and ferrite magnet?
Neodymium magnet (NdFeB):
It can be divided into bonded NdFeb and sintered NdFeb. Bonding is actually injection molding, while sintering is vacuum molding by high temperature heating. Neodymium magnets are by far the most powerful permanent magnets at room temperature (second only to holmium magnets at absolute zero, but far stronger than all known permanent magnets at room temperature). Material grades are N35-N52; Various shapes can be processed according to specific requirements: round, square, punching, magnetic tile, magnetic bar, convex, trapezoid, etc. Despite these advantages, the surface is easy to rust, so it is usually necessary to make some protective surface treatment: nickel plating, zinc plating, gold plating, epoxy plating, etc. The applicable ambient temperature of ordinary Ndfeb magnets is below 80 degrees, and the Curie temperature is 320~380 degrees.
Ferrite magnets (Ceramic):
It can be divided into sintered ceramic ferrite, injection molded ferrite. It is a permanent magnet material, composed of barium and strontium iron body, this magnetic material in addition to strong demagnetization performance, there are low cost advantages. Ferrite magnets are hard and brittle, requiring special machining technology. The opposite-sex magnet, because it is oriented in the direction of manufacture, must be magnetized in the direction taken, while the same sex magnet, because it is not oriented, can be magnetized in any direction, although a slightly stronger magnetic induction is often found on the smallest side of the compression surface. The magnetic energy product ranges from 1.1MGOe to 4.0MGOe. The applicable ambient temperature of ordinary ferrite magnets is below 250 degrees. Due to its low cost, ferrite magnets have a wide range of applications and are currently the most widely used permanent magnet materials.
Difference between neodymium magnets and ferrites in appearance:
Ferrite magnet: The texture of ferrite magnets is loose and there is no metallic luster, because of corrosion resistance and oxidation resistance, generally not electroplated, usually black.
Neodymium iron boron magnet: Neodymium magnets are basically electroplated, otherwise it is easy to rust. The coating is nickel copper nickel, zinc, gold, epoxy and so on. The surface color will be different according to the coating choice, more is nickel plating, the color is silver white
Difference between ceramic ferrite and rare earth Neodymium magnet in composition and structure;
Ferrite: Ferrite is an important oxide material, mainly composed of iron oxide (Fe2O3). Specifically, ferrite is a crystal structure composed of iron ions (Fe3+) and oxygen ions (O2-). Its chemical formula can be expressed as Fe3O4, where the molar ratio of iron ions to oxygen ions is 3:4.
Neodymium iron boron: Neodymium iron boron is an alloy composed of three elements: neodymium (Nd), iron (Fe), and boron (B). Their crystal structure is tetrahedral and belongs to hard magnetic materials.
Neodymium magnet composition detailed introduction;: Main composition and proportion of rare earth neodymium magnets
The difference between NdFeb and ferrite in gauss strength:
Ferrite magnet: According to the information, ferrite magnetic force is usually 500-1600 gauss, sintered ferrite density is 4.9(g/cm3), injection ferrite density is 3.8(g/cm3)
Ndfeb magnet: In the state of bare magnetic, Ndfeb magnetic force can reach about 3500 gauss. Sintered density 7.5(g/cm3), bonded neodymium magnet density 6(g/cm3)
The difference between NdFeb and ferrite in performance:
Ferrite magnets have a higher Curie temperature than neodymium magnets, so they retain magnetization better at higher temperatures. This gives the product more room to operate at higher temperatures than neodymium magnets. Although neodymium magnets with high coercivity can resist temperatures above 200 ° C (up to 230 ° C), the cost of these temperature grades is higher than that of lower temperature resistant grades. Ferrite can work all the way up to 300 ° C, and its temperature coefficient actually increases by 0.27% / ° C, which means that as the temperature increases, ferrite actually has stronger coercivity.
However, after more than 250 ° C, it is recommended to choose samarium-cobalt magnets, because at higher temperatures you do lose some magnetic field - 0.20% per degree Celsius as the temperature rises.
Not only temperature resistance, ferrite also has advantages over neodymium magnets in corrosion resistance and oxidation resistance, and neodymium magnets are also easy to rust because of poor corrosion resistance, so it is generally necessary to process the coating.
The difference between NdFeb and ferrite in price:
Neodymium magnets Although the magnetic force is much stronger than ferrite, but also because of high performance, it is used more, and the price is higher than ferrite. If it is made of low magnetic force, large size needs high temperature resistance, and used in humid environments, we generally recommend the use of ferrite material, if it is a fine small size magnet, you can consider neodymium magnets.
The advantages and disadvantages:
Advantages of ferrite magnet: high permeability, cheap price, temperature resistance and corrosion resistance, strong demagnetization performance, suitable for low-frequency applications
Ferrite magnet disadvantages: low magnetic force, non-smooth appearance and black.
Neodymium magnet advantages: Neodymium Magnets Are Easier to Machine than Ferrite Magnets, strong magnetic force, cost-effective, stable performance, a wide range of uses, can choose different color coating and luster, with good mechanical properties.
Disadvantages of Ndfeb magnet: poor temperature characteristics, fragile, high price is not suitable for large size, poor corrosion resistance and need coating.
To sum up, the choice of NdFeb or ferrite depends on the specific application needs, if you need strong magnetic properties and relatively small size, especially in low temperature environments, Ndfeb may be a better choice. For some low-power, high-temperature applications, ferrite may be more suitable.
The above is the difference between ferrite VS neodymium magnets, I hope it will help you. We are Courage magnet manufacturer, if there is a magnet purchase need, please contact us for customization.
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