This is part of a series of posts about abrasives. This is mostly cool SEM pictures, but I find them interesting. It’s quite difficult to image diamond at large magnifications, so there’s very limited information and pictures online about them.

This post is about very small diamond – nominal size is 0.25 µm, so 250 nm. This is already bordering on a nanoparticle, with all the difficulties that go along with this. Particles clump together like crazy, because weak surface forces such as van der waals forces are already larger than the mass of the particle. Sample preparation is a pain. And once you manage to prepare a nice monolayer on a very even substrate, diamond is non conductive, and very prone to charging effects. Luckily, the Zeiss GeminiSEM560 we have installed at Kern Microtechnik is an absolute champ at low voltage images.

Without further ado: 0.25 µm polycrystalline diamond.

SEM micrographs of 0.25 µm polycrystalline diamond. Sensor used is a SE1 InLens type. It shows very fine surface detail, but flattens the picture minimally. Low accelerating voltage and beam current with frame integration to reduce noise (about 100 frames / <1 sec frame time). At > 50kx magnification, beam deconvolution is used. Instrument: Zeiss GeminiSEM560

And the 0.25 µm monocrystalline diamond:

SEM micrographs of 0.25 µm monocrystalline diamond. Sensor used is a SE1 InLens type. It shows very fine surface detail, but flattens the picture minimally. Low accelerating voltage and beam current with frame integration to reduce noise (about 100 frames / <1 sec frame time). At > 50kx magnification, beam deconvolution is used. Instrument: Zeiss GeminiSEM560