Japan sintered NdFeB sintered magnet molding technology

On the hybrid and electric vehicle drive motor, Nd-Fe-B (neodymium - iron - boron) sintered magnet is the key component essential. Compared with other magnets, neodymium magnets not only strong magnetic force can be sufficient to drive the vehicle power, but also to reduce the motor size to a suitable vehicle use.

Such manufacturing neodymium magnet, an alloy containing the necessary need first to be comminuted into a particulate material, the particles come together to shape and then sintered. Then cut off into desired size to complete. This process always feel like making a cake.

Of course, in the actual production of high-quality neodymium magnet is not so simple. Not only to unify the 3 ~ 5μm particle size, but also pay attention to the uniformity of shape, but also consider the method of heating sintering, etc., it takes a lot of work to make. For example, the alloy pulverized to 3 ~ 5μm after implementation of the "magnetic field forming process" is one of them. This step is to fine powder (micro magnet) crushed orientation. Orientation here refers to the unity of a fixed direction, the higher the orientation of the magnetization direction of the powder, the greater the residual magnetic flux density. When implementing the first step of the fine powder is filled into a mold, applying a strong magnetic field on the powder be oriented, and then extruded into the implementation.

To achieve high orientation, we need inside the mold to create a uniform magnetic field space, which is also very important. Due to the size and configuration of the electromagnet mold, shape, material will cause the magnetic field is uneven, resulting in deterioration of orientation, thus utilizing the magnetic field analysis tools to fine-tune the magnetic field uniformity.

On the issue of manufacturing neodymium magnets, as many reports talking about it, to leave China out of the question. This is because the magnet is mixed in Dy (dysprosium) have mostly mined in China, but China has already begun to export restrictions. In this limit, Dy metal reducing supply on the market, the results of July 2011 Dy metal prices rose to $ 3100 / kg, reached a year ago about 10 times.

So why limit Chinese exports it? For this problem there are all kinds of speculation, but Japanese companies manufacture neodymium magnets give the same answer: "The reason is that we want to get the neodymium magnet manufacturing technology." Neodymium magnet currently share was almost monopolized by Japanese companies. And, as mentioned earlier, manufacture neodymium magnet requires a lot of accumulation of technology, and in this regard has been accumulated is the Japanese companies. In contrast, the Chinese "Although the manufacture of neodymium magnets have indispensable wealth of material, but it can not create a beautiful product." Therefore, China showed the "as long as the establishment of factories, our manufacturing technology professor in China, can supply a large number of raw materials," the exchange, which is one of the specific policies to restrict exports. Of course, more than just the Japanese magnet makers view.

July 2011, "Japanese Economic News" reported that Hitachi Metals decided to make neodymium magnets in China. Hitachi Metals is estimated at between stable procurement of materials and technology to make a choice after the outflow of risk, we decided to ensure that the first purchase.

However, even factories in China, it will not necessarily lead to immediate skills drain. On this issue, the process is relatively good Japanese car manufacturers. Japanese auto makers in order to sell cars in China, it is necessary to set up joint ventures with Chinese companies to build factories in China. And China can obtain the appropriate technology through joint ventures. "As allow the sale of cars on the huge Chinese market in exchange, we were asked to professors take years to accumulate engine technology", which can be described as exactly the same situation neodymium magnet