Thixotropically 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 first particle portion dispersed in the matrix portion and containing c-BN or w-BN as a main component. An average particle diameter of the first particle portion in a cross section is 10.0 μm or less, and an area fraction of the first particle portion in the cross section is 2.0% or more and 20.0% or less.

What is claimed is: 
     
         1 . A thixotropically molded product comprising:
 a matrix portion containing Mg as a main component; and   a first particle portion dispersed in the matrix portion and containing c-BN or w-BN as a main component, wherein   an average particle diameter of the first particle portion in a cross section is 10.0 μm or less, and   an area fraction of the first particle portion in the cross section is 2.0% or more and 20.0% or less.   
     
     
         2 . The thixotropically molded product according to  claim 1 , wherein
 an average particle diameter of the first particle portion in the cross section is 0.5 μm or more and 8.0 μm or less.   
     
     
         3 . The thixotropically molded product according to  claim 1 , further comprising:
 a second particle portion dispersed in the matrix portion and containing Mg 2 Si as a main component; and   a third particle portion dispersed in the matrix portion and containing MgO as a main component.   
     
     
         4 . The thixotropically molded product according to  claim 3 , wherein
 when a site in which at least one of the first particle portion, the second particle portion, and the third particle portion is aggregated to a size exceeding a particle diameter of 30 μm in the cross section is defined as an aggregated portion,   a total of the number of particles in the first particle portion, the number of particles in the second particle portion, and the number of particles in the third particle portion is defined as a total number of particles, and   a proportion of the number of aggregated portions to the total number of particles is defined as an aggregated portion number density,   the aggregated portion number density is 1000 ppm or less.   
     
     
         5 . The thixotropically molded product according to  claim 3 , wherein
 a total area of the second particle portion and the third particle portion in the cross section is 1.0 or more and 30.0 or less when an area of the first particle portion is 100.   
     
     
         6 . The thixotropically molded product according to  claim 1 , wherein
 Vickers hardness of a surface is 75 or more.   
     
     
         7 . A thixotropic molding material comprising:
 a metal body containing Mg as a main component;   boron nitride particles adhering to a surface of the metal body and containing c-BN or w-BN as a main component; and   a bonding portion interposed between the metal body and the boron nitride particles, wherein   an average particle diameter of the boron nitride particles is 10.0 μm or less, and   a ratio of the boron nitride particles to a total of the metal body and the boron nitride particles is 2.0 mass % or more and 15.0 mass % or less.   
     
     
         8 . The thixotropic molding material according to  claim 7 , wherein
 the bonding portion contains interposed particles which are made of an inorganic material and have an average particle diameter smaller than that of the boron nitride particles, or a resin.   
     
     
         9 . 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, boron nitride particles containing c-BN or w-BN as a main component, a binder, and a dispersion medium;   a stirring step of stirring the mixture; and   a drying step of adhering the boron nitride particles to a 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 boron nitride particles is 10.0 μm or less, and   in the mixture, a ratio of the boron nitride particles to a total of the metal body and the boron nitride particles is 2.0 mass % or more and 15.0 mass % or less.