Contactor and evaluation method of minute abrasion characteristic of monocrystalline diamond using the same

A contactor having an annular shape and made of a polycrystalline diamond including a plurality of diamond particles, the contactor being configured to have a rotation axis extending through a center of the contactor, the contactor comprising:

• a first portion having a constant thickness in a radial direction, the first portion including an inner end portion;
• and
• a second portion having a thickness decreasing in the radial direction, the second portion including an outer end portion,
• wherein the second portion has
• a first surface continuous with an upper surface of the first portion, a second surface continuous with a lower surface of the first portion, and a connection surface connecting the first surface and the second surface to each other and including the outer end portion,
• wherein, in a cross-section along the rotation axis,
• an angle θ formed by a first line segment indicating the first surface and a second line segment indicating the second surface is 100° to 150°,
• a length between a first boundary portion and a second boundary portion is 1 μm to 10 μm, the first boundary portion being a boundary between the first surface and the connection surface, the second boundary portion being a boundary between the second surface and the connection surface, and
• a length from the rotation axis to the outer end portion is 1 mm to 10 mm, and
• wherein an average particle diameter of the plurality of diamond particles is 0.1 μm to 100 μm.