METHOD FOR PRODUCING MnAL ALLOY

Abstract

An object of the present invention is to reduce a variation in the component of a MnAl alloy deposited by a molten salt electrolysis method to thereby obtain high magnetic characteristics. In a MnAl alloy manufacturing method that electrolyzes molten salt containing a Mn compound and an Al compound to deposit a MnAl alloy, the MnAl alloy is additionally charged into the molten salt during electrolysis. According to the present invention, the concentration of the Mn compound is maintained by additional charging of the Mn compound, so that it is possible to reduce a variation in the composition of the MnAl alloy to be deposited to thereby maintain stable production conditions.

1 . A method for manufacturing a MnAl alloy, the method comprising electrolyzing molten salt containing a Mn compound and an Al compound to deposit a MnAl alloy, wherein the method is characterized by additionally charging the Mn compound into the molten salt during electrolysis. 
     
     
         2 . The method for manufacturing a MnAl alloy as claimed in  claim 1 , wherein a concentration of the Mn compound in the molten salt is maintained at 0.2 mass % or more by additional charging of the Mn compound. 
     
     
         3 . The method for manufacturing a MnAl alloy as claimed in  claim 1 , further comprising performing a heat treatment to the MnAl alloy deposited by electrolysis. 
     
     
         4 . The method for manufacturing a MnAl alloy as claimed in  claim 3 , wherein a temperature of the heat treatment is set to 400° C. or more and less than 600° C. so as to impart metamagnetism to the MnAl alloy. 
     
     
         5 . The method for manufacturing a MnAl alloy as claimed in  claim 3 , wherein a temperature of the heat treatment is set to 600° C. or more and 700° C. or less so as to increase residual magnetization of the MnAl alloy. 
     
     
         6 . The method for manufacturing a MnAl alloy as claimed in  claim 3 , wherein the heat treatment is performed in an inert gas atmosphere or in a vacuum atmosphere. 
     
     
         7 . The method for manufacturing a MnAl alloy as claimed in  claim 1 , wherein a powdery MnAl alloy is deposited by performing electrolysis with an electricity amount of 50 mAh or more per 1 mass % of concentration of the Mn compound in the molten salt and per electrode area 1 cm 2 . 
     
     
         8 . The method for manufacturing a MnAl alloy as claimed in  claim 1 , wherein the molten salt further contains an alkali metal halide. 
     
     
         9 . The method for manufacturing a MnAl alloy as claimed in  claim 8 , wherein the molten salt further contains a rare earth halide or an alkaline earth halide. 
     
     
         10 . The method for manufacturing a MnAl alloy as claimed in  claim 1 , wherein a temperature of the molten salt during electrolysis is 150° C. or more and 700° C. or less, and an electricity amount per electrode area 1 cm 2  is 30 mAh or more and 120 mAh or less.