Pure copper plate

Abstract

This pure copper plate or sheet contains 99.96% by mass or greater of Cu, in which when an average crystal grain size of crystal grains in a rolled surface is represented by X μm and an amount of Ag is represented by Y mass ppm, an expression of 1×10−8≤X−3Y−1≤1×10−5 is satisfied, and when a ratio of J3, in which all three grain boundaries constituting a grain boundary triple junction are special grain boundaries, to all grain boundary triple junctions is defined as NFJE and a ratio of J2, in which two grain boundaries constituting a grain boundary triple junction are special grain boundaries and one grain boundary constituting the grain boundary triple junction is a random grain boundary, to all grain boundary triple junctions is defined as NFJ2, an expression of 0.30<(NFJ2/(1−NFJ3))0.5≤0.48 is satisfied.

1 . A pure copper plate or sheet comprising:
 99.96% by mass or greater of Cu,   wherein when an average crystal grain size of crystal grains in a rolled surface is represented by X μm and an amount of Ag is represented by Y mass ppm, a relational expression of 1×10 −8 ≤X −3 Y −1 ≤1×10 −5  is satisfied,   a surface orthogonal to a rolling width direction is used as an observation surface, measurement regarding a matrix is performed on a measurement area of 10000 μm 2  or greater at every measurement intervals of 0.25 μm by an EB SD method, measured results are analyzed by data analysis software OIM to obtain a CI value in each measurement point, a measurement point in which a CI value is 0.1 or less is removed, an orientation difference between crystal grains is analyzed, a boundary having 15° or more of an orientation difference between neighboring measuring points is assigned as a grain boundary, an average grain size A is acquired according to Area Fraction, measurement regarding the matrix is performed at every measurement intervals which are 1/10 or less of the average grain size A by the EBSD method, measured results are analyzed by the data analysis software OIM with a measurement area of 10000 μm 2  or greater in a plurality of visual fields such that a total of 1000 or more crystal grains are included to obtain a CI value in each measurement point, a measurement point in which a CI value is 0.1 or less is removed, an orientation difference between crystal grains is analyzed, and a boundary having 15° or more of an orientation difference between neighboring measuring points is assigned as a grain boundary, a coincidence boundary with Σ29 or less is defined as a special grain boundary, and the other grain boundaries are defined as random grain boundaries, in grain boundary triple junctions analyzed by the OIM, when a ratio of J3, in which all three grain boundaries constituting a grain boundary triple junction are special grain boundaries, to all grain boundary triple junctions is defined as NF J3  and a ratio of J2, in which two grain boundaries constituting a grain boundary triple junction are special grain boundaries and one grain boundary constituting the grain boundary triple junction is a random grain boundary, to all grain boundary triple junctions is defined as NF J2 , an expression of 0.30<(NET2/(1−NF J3 )) 0.5 ≤0.48 is satisfied.   
     
     
         2 . The pure copper plate or sheet according to  claim 1 , further comprising:
 Mg, and   Sn wherein   a total amount of Mg and Sn is in a range of 0.1 mass ppm or greater and 100 mass ppm or less.   
     
     
         3 . The pure copper plate or sheet according to  claim 1 , further comprising:
 Sn wherein   an amount of S is in a range of 1 mass ppm or greater and 20 mass ppm or less.   
     
     
         4 . The pure copper plate or sheet according to  claim 1 , further comprising:
 Pb;   Se; and   Te, wherein   a total amount of Pb, Se, and Te is in a range of 0.3 mass ppm or greater and 10 mass ppm or less.   
     
     
         5 . The pure copper plate or sheet according to  claim 1 , further comprising:
 Sr;   Ba;   Ti;   Zr;   Hf; and   Y, wherein   a total amount of Sr, Ba, Ti, Zr, Hf, and Y is 10 mass ppm or less.   
     
     
         6 . The pure copper plate or sheet according to  claim 1 , further comprising:
 Al;   Cr;   P;   Be;   Cd;   Ni; and   Fe, wherein   a total amount of Al, Cr, P, Be, Cd, Ni, and Fe is in a range of 0.3 mass ppm or greater and 10 mass ppm or less.   
     
     
         7 . The pure copper plate or sheet according to  claim 1 , wherein
 a ratio d max /d ave  of a maximum crystal grain size d max  to an average crystal grain size d ave  in a range of 50 mm×50 mm after a heat treatment maintained at 800° C. for 1 hour is 20 or less, and   the average crystal grain size d ave  is 400 μm or less.   
     
     
         8 . The pure copper plate or sheet according to  claim 1 ,
 wherein a Vickers hardness of the copper plate or sheet is 150 Hv or less.