United Magnet Technology Corp.

United States

These magnets are characterized by high magnetism, and are also resistant to both rust and high temperature.These magnets represent the highest magnetic energy product after neodymium magnets. They are also highly corrosion-resistant without being rustproofed and offer excellent temperature characteristics as well. These are rare-earth magnets resistant to high temperature.These sintered products consist mainly of samarium (Sm) and cobalt (Co), and are available with two kinds of material: 1-5 series and 2-17 series.The 1-5 series has high magnetic coercive force (Hcj), but is easy to magnetize and adjust magnetism. Magnets of this series also exhibit relatively stable performance under changing temperature.The 2-17 series has high magnetism and offers excellent temperature stability in magnetic characteristics as well. Samarium-cobalt magnets are relatively low in mechanical strength. Caution should therefore be exercised in handling these magnets to prevent chipping and cracking.

Microwave magnets can generate constant magnetic field to control electric current so that microwave signal is amplified and information can be smoothly transmitted. Microwave magnets are widely used in magnetrons, cathode-ray tubes, isolators

This type of magnet achieves the highest magnetic energy of all permanent magnets now in practical use. The main phase of the magnetism of rare-earth magnets developed conventionally was a two-component alloy. However, neodymium magnets combine neodymium with iron and boron to constitute a three-component, anisotropic-sintered rare-earth magnet with an atomic ratio of Nd 2 Fe 14 B 1.The neodymium magnet exhibits excellent performance in terms of size reduction, thinning, weight reduction and enhancing the efficiency of applied equipment. However, its magnetic characteristics and corrosion-resistance performance require caution in use of the product at high temperature. For the dynamic characteristics of the product at high temperature, the Br temperature characteristics of the magnet must be sufficiently considered.The main characteristics of neodymium magnets are as follows:a) Its maximum energy product (BH max) far exceeds that of ferrite (4.5 MGOe) and samarium-cobalt magnets (30 MGOe). Some models even exceed 48 MGOe.b) Since it consists mainly of relatively inexpensive neodymium and iron, it offers better cost performance than samarium-cobalt magnets that contain much cobalt, and poses no concern over availability.c) Although these magnets have temperature characteristics inferior to those of samarium-cobalt magnets, heat-resistant materials have been developed with higher magnetic coercive force for the following: NF-H series, NF-SH series and NF-UH series.d) Of the main components, iron accounts for nearly 70%. To ensure rustproofing, these magnets are equipped with Ni electrolytic plating as standard.

These magnets are based mainly on iron (Fe), aluminum (Al), nickel (Ni) and cobalt (Co). The magnets are fragile and not ductile. Therefore, after the raw metal is melted at high temperature and turned into an alloy, it is cast into a casting mold. These magnets are therefore also known as cast magnets.Al-Ni-Co magnets achieve high Br values and high temperature stability, readily cause low-temperature demagnetization and thermal demagnetization, achieve high mechanical strength, and offer other advantages. However, these magnets have low magnetic coercive force (Hcj) and readily undergo demagnetization due to an external magnetic field, are unsuited for thin products, and placed under other constraints. In the design process, it is therefore important to select a method of magnetization that allows for sufficient shape and magnetic characteristics, and a method of assembly in which consideration is given to demagnetization.Alnico magnets can be manufactured in one of two ways. The most common method is by casting, but there are times when sintering is also suitable in production. Aluminum, Cobalt, Nickel, Copper and Iron are the components that make up this alloy. Due to its brittle nature, Alnico magnets are not really suitable for structural use. Despite this, its still a very hard substance, so drilling and machining it can be a challenge.Regardless of the method of production (casting or sintering), it can be used for various applications in its off the shelf state. However, a smoother surface can be created by precision grinding, which will increase its tolerance and usefulness still further, but as you might expect, this is more expensive.Due to the nature of production (if casting, sand molds need to be made and if sintering, the process will need die presses), ordering a small amount of the magnets is usually cost prohibitive. It can be done, but is likely to feature increased charges or at the very least a minimum quantity order requirement.There are various grades of Alnico available at United Magnets, although the main standard grade is Alnico 5. The different production methods will also present slightly different finishes to the magnet structure, for example, if they have been cast, there will be tiny air holes present, whereas those produced by sintering will not have these holes. They also sometimes have a protective coating added. This is generally considered unnecessary because the corrosion resistance is already very high. If not for protection, there will sometimes be a coating added to simply make it look nicer. The Alnico Red Magnet range is, as the name suggests, after a red coating has been added to the product.