High temperature coating for optimal processes and efficiency
When a substrate is subject to heat and rapid temperature fluctuations, it can lead to surface breakage and corrosion. Electrical and engine components, chimneys and ovens, pipework and chemical plants, all these are exposed to possibly damaging temperatures and conditions. A high temperature coating (also a heat resistant paint or thermal management coating) works to protect the substrate from variations and extremes of temperature without losing functionality allowing for optimised processes and increased efficiency. As well as protecting from heat, these coatings:
- Protect from corrosion under insulation (CUI): High temperature coatings for steel provide an extra layer of protection between the hot surface and insulation
- Effective temperature range up to 1000°C: Different formulations of high temperature coating for metal provide resistance to temperatures from -196°C to 1000°C
- Abrasion resistant: Suitable for rough environments
- Reduce thermal fatigue: Heat resistant coating improves performance of machinery and extend part life
- Allow for higher operating temperatures while limiting thermal exposure
In this article we look at the different categories of high temperature coating, how to choose the right one for your project, and where to find products and contractors in New Zealand.
Choose the best high temp paint for your purposes
High temperature coating is the one that protects surfaces from overheating and failing due to high heat. Note that these coatings do not necessarily protect from flames. Essentially, heat resistant coatings can be divided into four types:
1. Anti corrosive & heat resistant sprayed metal coatings
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.
2. Liquid high heat coatings
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
- Benefits: Liquid paints have the benefit of being able to be applied to hot substrates without affecting the coating.
- Uses: Applied at new construction, on-site and as a maintenance coating.
3. Heat resistant powder coatings
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
- Benefits: being VOC free and having a wide range of gloss and colour finishes
- Uses: Becoming more and more popular as high temperature coating for metal; can be applied instead of liquid heat resistant coating on ferrous metals (steel) offsite.
4. Ceramic high temperature paints
The heat resistance properties of ceramic coating are well known, and some of the highest heat coatings available are ceramics. Heat resistant ceramic paints are known among car enthusiasts for manifold and engine component protection (such as ceramic exhaust coating), but they also have a reputation as industrial heavy duty and offshore high temperature coating.
- Temperature resistance: up to +1000
- Benefits: Heat resistant ceramic paint also provides corrosion protection and chemical resistance and a hard finish.
- Uses: applications that require the highest protection from temperatures: car underhood parts, heavy duty industrial machinery, offshore structures etc.
Base your choice of heat resistant paint on the following
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 heat resistant paint:
1. 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.
For example, International Intertherm 50 is recommended for temperatures up to 540°C
2. 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.
For example, PPG HI-TEMP 1027 is designed to prevent CUI and can be applied to hot substrates
3. 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.
For example, Jotun Epoxy HR can be applied on substrates up to 150oC
Heat resistant paint NZ – products and specialists
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 across the New Zealand, 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 high temperature 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.
|High temperature 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 high temperature Topcoat||Silicone-based topcoat with an aluminium finish for bare steel or primed surfaces||Heat resistance up to 425oC||16m2 per litre|