Platinum-black coatings for infrared emitters

Abstract

The technology of covering of IR sources with high emissivity materials was worked out. Platinum black was electrodeposited from H2PtC16 solution on platinum foil. The current densities from 0.1 to 5 mA/mm2 and the deposition time from 1 to 15 minutes were employed. The microstructures of platinum black were examined using scanning electron microscopy. For the current densities below 1 niA/mm2 the island structures were received. For the current densities from 1 to 2 mA/mm2 first the island structure arises, next it changes to the sponge structure. For the current densities above 2 mA/mm2 only the sponge structures were observed. For the island structures multiple increases of emissivity coefficient were discovered. Instead, for the sponge structures the increase of emissivity coefficient was much lesser. The value of emissivity coefficient for examined covers was about 0.8 at temperature 1000°C. For the obtained IR sources stable work without changing the parameters is possible for the temperature up to 800°C.

Optical gas sensing: a review

“…An example of a single emitter is shown in Figure 17. Different coatings have been applied to confer improved properties, namely platinum black for increased emissivity compared to a plain metal surface [98] , SnO 2 :Sb for improved long-term stability at high operating temperatures (giving an estimated lifetime of 10 years at 950°C [97] ) and Si 3 N 4 for longer wave (9-12 μm), lower temperature (600°C) operation [96] . Microstructured coatings, with features on a scale similar to the target wavelength, have been used to improve spectral efficiency, though these have not yielded spectral emission above the level dictated by the Planck emission curve for unit emissivity.…”

“…Different coatings have been applied to confer improved properties, namely platinum black for increased emissivity compared to a plain metal surface [98], SnO 2 :Sb for improved long-term stability at high operating temperatures (giving an estimated lifetime of ten years at 950 • C [97]) and Si 3 N 4 for longer wave (9-12 μm), lower temperature (600 • C) operation [96].…”

Infrared emitting nanostructures for highly efficient microhotplates

“…Some solutions are known to increase the broadband emission coefficient, each with its specific assets and drawbacks. For example, metal blacks like 'platinum-black' or 'gold-black' can be used as a highly emissive or absorbing coating [15][16][17][18][19][20][21]. It is deposited in a modified evaporation process or, alternatively, by electroplating deposition.…”

“…But for IR emitting hotplates, one has also to focus on the emissivity of the heated surface. Some hotplates are presented featuring a narrowband emissivity improvement by periodic microstructures [42,43], and only a few hotplates with increased broadband emissivity [15], with the already mentioned drawbacks.…”