COPPER POWDER AND MANUFACTURING METHOD THEREOF

PROBLEM TO BE SOLVED: To provide copper powder which allows an electrical conductor to hardly cause defects such as cracks and blisters.SOLUTION: The copper powder includes a plurality types of flat particles having different aspect ratios. In order to obtain the aspect ratio of copper powder, 300 or more pieces of particles are measured. The aspect ratio ranging from 1.00 to 3.00 is divided into 30 sections with a width of 0.10. The median of each section is taken as the representative value of the section. The appearance frequency in each of the sections is plotted with respect to the central value. The neighboring plotted points are connected with segment lines to make a line graph. In the graph, all of the segment lines corresponding to the central values ranging from 1.35 to 1.85 have negative or zero gradients, respectively.SELECTED DRAWING: Figure 1 【課題】導電体にクラックやブリスター等の欠陥が発生しづらくなる銅粉を提供すること。【解決手段】銅粉は、アスペクト比の異なる複数種類の扁平粒子を含む。銅粉のアスペクト比を３００個以上の粒子について測定し；１．００から３．００までのアスペクト比の範囲を、０．１０の幅で３０個の区間に分け；前記区間の代表値として該区間の中央値をとり、該中央値に対して該区間に含まれる個数頻度をプロットし；隣接するプロット間を線分で結んだ折れ線グラフを作成したとき、前記中央値が１．３５から１．８５までの間のすべての線分の傾きが、それぞれ負の値であるか又は０である。【選択図】図１