Heat resistant coating protects from temperature extremes and fluctuation
When a substrate is subject to extreme heat and rapid temperature fluctuations, it can lead to surface breakage and corrosion. For example electrical and engine components, chimneys and ovens, pipework and chemical plants are exposed to possibly damaging temperatures and conditions and can be protected with a coating. A heat resistant coating (also known as thermal management coating) works to protect the substrate from variations and extremes of temperature without losing functionality. In addition to protecting from heat, these coatings have more benefits.
- CUI protection: High temperature coatings for steel provide an extra layer of protection between the hot surface and insulation preventing corrosion under insulation
- Resistance up to 1000°C: Different formulations of heat resistant coating for metal provide resistance to temperatures from -196°C to 1000°C
- Abrasion resistance: Suitable for rough environments
- Reductio of thermal fatigue: Heat resistant coating improves performance of machinery and extend part life
- Allowance for higher operating temperatures while limiting thermal exposure
In this article we look at the different categories of heat resistant coating, how to choose the right one for your project, and where to find products and contractors in Hong Kong.
Defining the high temperature coating – How to choose the right one?
As with any coating application, understanding the needs of your substrate and the application process is crucial for making the right coating choice. As well as knowing the substrate type, you need to know its environment, its use, the coating time parameters, and the likely ways it will fail. Here are some questions you need to ask before you can choose a high temperature coating:
- What is the maximum temperature of the substrate that you wish to protect?
One of the most common reasons for failure is expecting high temperature coatings to perform outside of the temperature range they were manufactured to tolerate. Each coating type has a specific temperature range, and outside it the functionality and efficacy fails. Make sure not to understate the maximum temperature.
- Is the substrate insulated?
If you are choosing a heat resistant coating for metal to combat CUI, that coating needs to be specially formulated for the purpose. It needs corrosion resistance, but it also needs to be able to be applied to hot substrates and deal with boiling water exposure.
- What will the substrate temperature be during application?
There are high temperature coatings formulated for hot (up to 300oC) and ambient temperature application. A hot application may be required to avoid needing to shut down operations, spot coating problem areas, and generally not disrupting a facility.
Dividing heat resistant coating types into 4 groups
It is important to note that while high temperature coating does provide some protection from flames, it is not a fire resistant coating. Essentially, heat resistant coatings can be divided into four types:
1. Liquid paints
The liquid high temperature coatings are usually either epoxy or silicone based. The general rule is that the more silicone the coating contains the higher temperatures it can resist. These coatings exist as single and two component systems and are formulated on water or solvent base.
- Temperature resistance: Up to +550
- Uses: Applied at new construction, on-site and as a maintenance coating.
- Benefits: Liquid paints have the benefit of being able to be applied to hot substrates without affecting the coating.
As well as being corrosion resistant, high temperature powder coatings have been developed for heat resistance to medium to high temperatures. The powders are usually epoxy and silicone-based (like the liquid paints), and silicone-based powders perform better at higher heats.
- Temperature resistance: from 200 to 600°C
- Uses: Becoming more and more popular as heat resistant coating for metal; can be applied instead of liquid heat resistant coating on ferrous metals (steel) offsite.
- Benefits: being VOC free and having a wide range of gloss and colour finishes
The heat resistance properties of ceramic coating are well known, and some of the highest heat coatings available are ceramics. Ceramic coatings are known among car enthusiasts for manifold and engine component protection, but they also have a reputation as industrial heavy duty and offshore high temperature coating.
- Temperature resistance: up to +1000
- Uses: applications that require the highest protection from temperatures: car underhood parts, heavy duty industrial machinery, offshore structures etc.
- Benefits: Heat resistant ceramic paint also provides corrosion protection and chemical resistance and a hard finish.
4. Sprayed metal
Of all the sprayed metal coatings, thermal spray aluminium (TSA) is the most common. TSA and sprayed metal and metal additive coatings are usually applied on steel to provide protection from corrosion and high temperatures.
- Temperature resistance: from -50 to +550°C
- Uses: Thermal sprayed aluminium is particularly used as high temperature coatings for steel for CUI prevention in onshore and offshore platforms and processing plants.
- Benefits: Excellent corrosion protection combined with heat resistance.
Heat resistant coatings in Hong Kong: products & services
Heat resistant coatings are used across a wide range of industries, as well as by homeowners and barbecue enthusiasts. As such, a wide range of products and services are available in Hong Kong, no matter your project. Below is a table outlining just a few of the products and their uses, as an indication. Heat resistant coatings should be applied by a trained professional. If you would like more information about heat resistant coatings, or would like to connect with one of our partners to coat your project, contact us! Our experts are here to help, just use the “Request a quote” button below the article and take advantage of our 100% free quote service.
For information on where to find high temperature powder coating, please visit our powder coating services page.
|Heat Resistant Coating Product||Product Description||Applications||Theoretical Coverage|
|PPG HI-TEMP 1027||One component, silicone-based ceramic coating for carbon steel and stainless steel||CUI prevention in chemical/petrochemical, power, and offshore market segments up to 650°C||5.8m2 per litre for 125 microns|
|International Intertherm 50||Single components, silicone-based high temperature coatings for steel||Corrosion protection in fire stacks, chimneys, exhausts, vents and pipework up to 540°C||18m2 per litre at 25 microns|
|Jotun Solvalitt Midtherm||Single component silicone acrylic heat resistant coating for metal; steel and aluminium||Corrosion protection for insulated and non insulated surfaces up to 260°C||11.3m2 per litre|
|Rust-Oleum 4200 Heat Resistant Topcoat||Silicone-based topcoat with an aluminium finish for bare steel or primed surfaces||Heat resistance up to 425oC||16m2 per litre|