Nd-fe-b Permanent Magnet Materials. Gadolinium And Yttrium Preparation Process Research

NdFeB permanent magnet exhibits the highest magnet properties and optimal performance price ratio of all magnet materials, from its inception in 1983, its industries have been the rapid development and widely used in every field of the national economy. With the rapid growth of new rare-earth materials market such as NdFeB permanent magnet material, stimulating the rapid development of rare earth industry, leading to the production scale and capacity of rare earth is much larger than the consumption capacity, and the application of rare earth elements is a serious imbalance, increase the risk of enterprises operation, affect the healthy development of rare earth industry. Therefore, we should speed up the application development of these rare earth elements, look for the new applied fields, keep the balance of the consumption of all rare earth elements. In this paper, it is feasible by means of using low-cost and relative overproduction of gadolinium and yttrium partially replaces the traditional process of neodymium, praseodymium, dysprosium and other rare earth elements preparing new NdFeB permanent magnet materials. Specific study of this article content as follows:The experiment adopts the gadolinium iron alloy, the yttrium iron alloy or the gadolinium yttrium iron alloy to replace pure rare-earth metal producing NdFeB permanent magnetic materials, reduce its cost of production greatly, also decrease the environmental pollution; at the same time, it makes gadolinium, yttrium have a new application field, solve the problem of a great many of gadolinium, yttrium which is set aside, and improve the utilization of rare-earth resources.The key to this experiment is hydrogen explode and two-stage tempering process. The hydrogen explodes can make alloys dehiscence along the Nd-rich phase, make sure the integrity of the grain of Nd₂Fe₁₄B and Nd-rich phase. Using the two-stage tempering process, exceptionally the lower temperature is 500℃(generally that is 600℃) and the extention of the time is 300mins, we can get the optimal magnet properties.For the new type of NdFeB permanent magnet, with the addition of gadolinium, yttrium increasing gradually, remanence and maximum magnetic flux density unilateral decline, but the intrinsic coercivity changed little, slightly first and then decreasing.When the content of gadolinium, yttrium at 2wt%, the intrinsic coercivity is best, but when it is more than 2wt%, the intrinsic coercivity decreases rapidly. At the same time, adding gadolinium,yttrium compound prepared NdFeB permanent magnet is better than the integrated magnetic properties of gadolinium, while adding gadolinium prepared NdFeB permanent magnet has magnetic properties better than the preparation of NdFeB with yttrium.Add a certain content of gadolinium,yttrium can effectively improve the corrosion resistance of NdFeB permanent magnet, and use the combined addition of Tb,Dy,Cu,Al and other elements, the magnetic properties and corrosion resistance are both increase to some extent.We first use the new technology of preparation of new rare-earth permanent magnet, which use gadolinium,yttrium partially replace Pr,Nd,Tb,Dy. The magnetic of the product can reach the original technical indexes of medium and high grade NdFeB, and the thermal stability, corrosion resistance, working temperature is much higher; which can save a 10～30% dosage of Pr,Nd,Tb,Dy and a 5～10% lower reduction cost, and the comprehensive utilization of rare-earth resources is improved too.