Surface flatness is an important issue for thermal designers as it is directly related to thermal contact resistance between surfaces. In this column, the definitions of surface flatness related parameters are discussed. These definitions are presented here as in the ASME B46.1-1995 standard [1]. Surfaces are characterized by three main parameters: roughness, waviness, and … [Read more...]
E missivity in Practical Temperature Measurements
When making temperature measurements with infrared cameras and point detectors, we are always facing the question of the emissivity of our sample. In practice we would like to have a single number set in the IR device. To approach the question, let's first recall some fundamental definitions. Planck's radiation law gives the energy density emitted by a blackbody as a function … [Read more...]
Glass: A Group Of Familiar Materials With Varying Properties
The knowledge to manufacture glass products is already 4500 - 5000 years old, and glass in its different compounds is one of the most commonly used man-made materials. The material technical definition of glass is loose, but, typically, inorganic products manufactured by fusing and then solidifying without crystallizing can be categorized as glasses. In the electronics industry … [Read more...]
Pyrolytic graphite – thermal performance by structure
Continuing our discussion of different forms of carbon, this column addresses the topic of pyrolytic graphite, a material that opens up many interesting applications not only for cooling but also for scientific measurement equipment. Pyrolytic graphite - the finest forms of which are often called Highly Ordered Pyrolytic Graphite (HOPG) - is manufactured through a pyrolysis … [Read more...]
Diamonds are a Thermal Designer's Best Friends
Different forms of carbon, such as processed natural graphite, pyrolytic graphite, diamond-like carbon, and synthetic diamond, offer lots of possibilities for maximizing conductive heat transfer.Synthetic diamond has already found its place as a common solution for heat spreaders inside semiconductor laser components, where temperature stabilization is of utmost importance for … [Read more...]
