Magnesium alloy chips and process for manufacturing molded article using same

Abstract

There is provided chips for injection molding wherein the surfaces of chips made of an aluminum-containing magnesium alloy are coated with carbon powder. A molded article produced by injection molding of such chips for injection molding had excellent bending properties and tensile strength, which vary in a small range. Furthermore, a scrap formed during injection-molding of the chips for injection molding has improved recyclability.

1 . Chips for injection molding wherein the surfaces of chips made of an aluminum-containing magnesium alloy are coated with carbon powder. 
     
     
         2 . The chips for injection molding as claimed in  claim 1 , wherein a content of said carbon powder is 0.01 to 3% by weight. 
     
     
         3 . The chips for injection molding as claimed in  claim 1 , wherein said carbon powder is carbon black. 
     
     
         4 . The chips for injection molding as claimed in  claim 3 , wherein said carbon black has an average primary particle diameter of from 5 to 100 nm and a DBP absorption of from 40 to 200 mL/100 g. 
     
     
         5 . A process for manufacturing the chips for injection molding as claimed in  claim 1 , comprising mixing chips made of an aluminum-containing magnesium alloy with said carbon powder. 
     
     
         6 . A process for manufacturing a molded article made of a magnesium alloy, comprising charging the chips for injection molding as claimed in  claim 1  in an injection-molding machine and then injection-molding the chips. 
     
     
         7 . The process for manufacturing a molded article as claimed in  claim 6 , wherein in said molded article, a complex of aluminum and carbon is dispersed in a magnesium matrix. 
     
     
         8 . A process for manufacturing an ingot made of a magnesium alloy, comprising heat-melting a scrap formed during injection-molding of the chips for injection molding as claimed in  claim 1  in the presence of a flux and then cooling it. 
     
     
         9 . The process for manufacturing an ingot as claimed in  claim 8 , wherein a ratio (C 2 /C 1 ) of a carbon content C 2  (% by weight) in said ingot to a carbon content C 1  (% by weight) in said scrap is 0.1 or less.