Composite polycrystal and tool with composite polycrystal
A polycrystalline composite comprising diamond particles and non-diamond carbon, wherein: the sum of the content Vd of the diamond particles and the content Vg of the non-diamond carbon is more than 99% by volume based on the total volume of the polycrystalline composite; the median diameter d50 of the diamond particles is 10 nm or more and 200 nm or less; the dislocation density of the diamond particles is 1.0×10 13 m −2 or more and 1.0×10 16 m −2 or less; and the content Vd of the diamond particles and the content Vg of the non-diamond carbon satisfy the relationship represented by the formula 1:0.01<Vg/(Vd+Vg)≤0.5 Formula 1.
1 . A polycrystalline composite comprising diamond particles and non-diamond carbon, wherein:
a sum of a content Vd of the diamond particles and a content Vg of the non-diamond carbon is more than 99% by volume based on the total volume of the polycrystalline composite;
a median diameter d50 of the diamond particles is 10 nm or more and 200 nm or less;
a dislocation density of the diamond particles is 1.0×10 13 m −2 or more and 1.0×10 16 m −2 or less; and
the content Vd of the diamond particles and the content Vg of the non-diamond carbon satisfy a relationship represented by formula 1:
0.01
<
Vg
/
(
Vd
+
Vg
)
≤
0.5
.
Formula
1
2 . The polycrystalline composite according to claim 1 , wherein the dislocation density of the diamond particles is 2.0×10 15 m −2 or more and 1.0×10 16 m −2 or less.
3 . The polycrystalline composite according to claim 2 , wherein the dislocation density of the diamond particles is 2.0×10 15 m −2 or more and 7.0×10 15 m −2 or less.
4 . The polycrystalline composite according to claim 1 , wherein the median diameter d50 of the diamond particles is 10 nm or more and 100 nm or less.
5 . The polycrystalline composite according to claim 1 , further comprising boron, wherein
a content of the boron is 0.01% by mass or more and 1% by mass or less based on a total mass of the polycrystalline composite.
6 . The polycrystalline composite according to claim 1 , wherein the content Vd of the diamond particles and the content Vg of the non-diamond carbon satisfy a relationship represented by formula 2:
0.03
≤
Vg
/
(
Vd
+
Vg
)
≤
0.4
.
Formula
2
7 . The polycrystalline composite according to claim 1 , wherein a content of at least one metal element selected from the group consisting of a Group 4 element, a Group 5 element and a Group 6 element in the periodic table, and iron, aluminum, silicon, cobalt and nickel is less than 1% by volume.
8 . The polycrystalline composite according to claim 1 , wherein a content of at least one inevitable impurity selected from the group consisting of hydrogen, oxygen, nitrogen, an alkali metal element and an alkaline earth metal element is less than 0.1% by volume.
9 . A tool comprising the polycrystalline composite according to claim 1 .