Molded Product, Thixotropic Molding Material, And Method Of Producing Thixotropic Molding Material

Abstract

A thixotropically molded product includes: a matrix portion containing Mg as a main component; and a particle portion dispersed in the matrix portion and containing α-Al2O3 as a main component. In a cross section, a total area fraction of the particle portion in a range of 500 μm square around a point at a depth of 1 mm from a surface is 0.5% or more and 30.0% or less.

What is claimed is: 
     
         1 . A thixotropically molded product comprising:
 a matrix portion containing Mg as a main component; and   a particle portion dispersed in the matrix portion and containing α-Al 2 O 3  as a main component, wherein   in a cross section, a total area fraction of the particle portion in a range of 500 μm square around a point at a depth of 1 mm from a surface is 0.5% or more and 30.0% or less.   
     
     
         2 . The thixotropically molded product according to  claim 1 , wherein
 when a 2θ diffraction pattern is obtained by X-ray diffraction, the 2θ diffraction pattern has an Mg peak assigned to a (100) plane of Mg and an Al 2 O 3  peak assigned to a (012) plane of α-Al 2 O 3 , and   the 2θ diffraction pattern satisfies I(Mg)>I(Al 2 O 3 ), where I(Mg) is an intensity of the Mg peak, and I(Al 2 O 3 ) is an intensity of the Al 2 O 3  peak.   
     
     
         3 . The thixotropically molded product according to  claim 1 , wherein
 a Young's modulus is 46 GPa or more,   tensile strength is 180 MPa or more,   an electrical conductivity is 9% IACS or less, and   a linear expansion coefficient is 20×10 −6 /K or less.   
     
     
         4 . A thixotropic molding material comprising:
 a metal body containing Mg as a main component;   alumina particles adhering to a surface of the metal body and containing α-Al 2 O 3  as a main component; and   a bonding portion interposed between the metal body and the alumina particles, wherein   an average particle diameter of the alumina particles is 20.0 μm or less, and   a ratio of the alumina particles to a total of the metal body and the alumina particles is 1.0 mass % or more and 20.0 mass % or less.   
     
     
         5 . The thixotropic molding material according to  claim 4 , wherein
 the bonding portion contains interposed particles which are made of an inorganic material and have an average particle diameter smaller than the average particle diameter of the alumina particles, or a resin.   
     
     
         6 . The thixotropic molding material according to  claim 5 , wherein
 the inorganic material is a silicon oxide.   
     
     
         7 . The thixotropic molding material according to  claim 4 , wherein
 the metal body contains at least one of aluminum and zinc.   
     
     
         8 . A method of producing a thixotropic molding material comprising:
 a preparation step of preparing a mixture containing a metal body containing Mg as a main component, alumina particles adhering to a surface of the metal body and containing α-Al 2 O 3  as a main component, a binder, and a dispersion medium;   a stirring step of stirring the mixture; and   a drying step of adhering the alumina particles to the surface of the metal body via the binder by removing at least a part of the dispersion medium from the stirred mixture, wherein   an average particle diameter of the alumina particles is 20.0 μm or less, and   in the mixture, a ratio of the alumina particles to a total of the metal body and the alumina particles is 1.0 mass % or more and 20.0 mass % or less.