Graphite is anisotropic by nature, but still easily tested with the Hot Disk method. There are several approaches to testing graphite samples, where the testing of high-conducting graphite sheets has become important over the last few years.
To test graphite sheets is easy with the Hot Disk slab measurement method and samples as thin as 45 microns can be tested with this tool. To date, sheets with thermal conductivity up to ca 1500 W/m/K have been analysed with this application.

Not only graphite sheets can be tested with a Hot Disk instrument. In the pictures below testing of anisotropic bulk graphite and stacks or laminates of graphite sheets are depicted. This type of testing is achieved by the anisotropic measurement module, which yields the thermal conductivity, both in and through the plane, from a single transient.