High-emissivity coating systems (such as high temperature black coating) have been identified as a means of improving energy efficiency and product quality when they are applied to refractory linings of industrial furnaces.
Some furnaces, incinerators and heaters have been in service for over 20 years, however over time thermal coatings can fail due to thermal expansion mismatches between coatings and substrates and also misapplication. This article will discuss the importance of high temperature black coating and its application.
What are High-Emissivity Coatings?
High temperature black coating is a form of high emissivity coating which is used as an indicator of the level of heat a material can absorb and, when conditions are right, reradiate to a cooler area. The emissivity scale is a range of 0-1; 1 is a black body, absorbing all of the energy exposed to it and 0 is a reflector which does not absorb any energy at all.
High-emissivity coatings such as high temperature black coating help control radiative heat transfer by forming custom surface emissivity. High temperature black coating can be added to metal and ceramic surfaces which are exposed to extremely high temperatures in production/service, leading to improved heat transfer, throughput and processing conditions.
Radiative Heat Transfer using High Temperature Black Coating
Radiative heat transfer is very important at high temperatures in which standard thermal insulation methods are not effective. Managing the flux is critical for the improvement of process efficiencies and enhancing material strength and durability in a range of industrial processes. The influence of radiative heat transfer is significant, particularly as temperatures go over 600°C.
High temperature black coating helps to maintain high emissivity values in high temperature production or service areas, which is a key challenge in industrial applications. The main issue is that standard emissivity agents may break down in challenging applications such as engines, reducing environments; such as fuel processing, and vacuum environments; such as space or semiconductor manufacturing. This means that the traditional coating materials do not work and high temperature black coating is a brilliant alternative.
High temperature black coating is also effective as it is able to withstand thermal cycling, is stable and compatible with other close contact materials and minimize diffusion of corroding species into the substrate material.
High Temperature Black Coating from Aremco
At Aremco, our HiE-Coat™ 840-Series line of high emissivity coatings are black-body formulations which have been created to substantially enhance the thermal efficiency of infrared heaters, incinerators, furnaces and ovens which are used in the ceramics, appliance, metallurgical, chemical processing and refining industries. These high temperature black coatings can lead to a 5-10% saving in natural gas and oil heating costs.