Disproportionation Reaction Of Gd-Co Alloy Induced By High-energy Ball-Milling In Heptanes And Its Application

Aiming at the development of new preparing technique of rare earth permanent magnets, the disproportionation reaction of several rare earth transition compounds high-energy ball-milled in heptane have been investigated. Detailed works are as follows.1. High-energy ball-milled in heptane, Gd Co₅ compound disproportioanted into Gd H2+δ and α-Co。The H atom come from the decomposion of heptane. heated to 800 ℃ under vacuum, Gd H2+δ decomposes and Gd₂Co₁₇ is formed. Small amount of Gd Co₅ phase remains in the samples with short mill time（400 minutes） and enhance the permanent properties, due to the incomplete disproportionation reaction. Extension of mill time results the appearance of α-Co and Gd Co C2 phases2. Gd_1.2Co₅ alloy with increased content of Gd was processed by the identical technique as above. It is found that more content of Gd results the appearance of magnetically hard Gd Co₅ phase in the final product and increases its permanent magnetic properties. While the increase of Gd also increase the proportion of α-Co and Gd Co C2 phases.3. Light rare earth transition compound YCo₅ alloy was processed by the identical technique as above. YCo₅ alloy shows a behavior similar to that of Gd Co₅, only there is no magnetically hard YCo₅ phase in the sample with the shortest mill time（400 minutes）. Short ball mill time is more suitable for the sake of permanent magnetic properties of light rare earth transition compound prepared by this technique.It can be concluded from this work that:1. it is an universal law that the R-T（R=rare earth） compounds disproportionate into rare earth hydrides and α-Co when they are high-energy ball-milled in heptane.2. The product after desorpion reaction is prone to be R2Co17 rather than RCo₅.