Here are some factors that can affect the service life of high-temperature resistant coatings:
Temperature factor
High temperature level: The higher the actual working temperature that the coating is exposed to for a long time, the greater the destructive effect on its structure and properties. For example, a high temperature resistant coating with a temperature rating of 800 ℃ may experience rapid decomposition of organic components and sintering or phase transformation of inorganic components in the coating if it is operated in an environment close to or exceeding this temperature limit for a long time, leading to cracking and peeling of the coating and significantly shortening its service life; If the working temperature is much lower than its upper temperature limit, the coating performance can be relatively more stable and the service life will be longer.
Temperature fluctuations: Frequent temperature changes can cause the coating to repeatedly undergo thermal expansion and contraction, resulting in thermal stress. For example, in some intermittent industrial furnaces, the coating undergoes rapid temperature fluctuations and thermal stress accumulation as the equipment starts and stops, which can easily cause the coating to detach from the substrate surface or produce internal cracks, thereby affecting its normal use and reducing its service life, even if its maximum working temperature does not exceed the temperature resistance range.
Environmental media factors
Corrosive gases: In industries such as petrochemicals and metallurgy, corrosive gases such as sulfur dioxide, hydrogen sulfide, and hydrogen chloride are often present around equipment. These gases can react chemically with the coating, eroding it and causing it to gradually thin and lose its protective function. For example, in the acidic environment of refineries containing a large amount of hydrogen sulfide, organic silicon high-temperature resistant coatings can accelerate the aging and decomposition of coatings, leading to premature failure. Coatings that may have a service life of 5 years may only last for 2-3 years in such harsh environments.
Corrosive liquids: If the surface of the coating is frequently exposed to corrosive liquids such as acid, alkali, salt, etc., it can also cause corrosion damage to the coating. For example, in a chemical reactor, the coating needs to resist the erosion and immersion of various acidic and alkaline liquids in the reaction materials. Over time, the coating will be corroded and penetrated, and it will no longer provide protection, greatly reducing its service life.
Dust particles and impurities: In some high-temperature industrial environments, such as rotary kilns in cement plants and flues in thermal power plants, there are a large number of dust particles in the air. These particles are washed away by high-speed airflow on the surface of the coating, causing wear and tear, gradually thinning the coating, increasing surface roughness, and affecting its high temperature resistance, corrosion resistance, and other properties, shortening its service life.
Matrix material factors
Surface roughness of the substrate: If the substrate surface is too smooth, the adhesion between the coating and the substrate may be insufficient; If the surface roughness is too large, it is easy to cause uneven thickness of the coating during coating, resulting in local weak points. Appropriate surface roughness can enhance the mechanical adhesion between the coating and the substrate, improve adhesion, and make the coating less prone to detachment during use, which is beneficial for extending its service life. For example, when the surface roughness of the substrate reaches 30-50 μ m through sandblasting treatment, the adhesion of the coating is better, and the service life of the coating can be extended compared to situations where the roughness does not meet the requirements.
Characteristics of substrate material: Different substrate materials have varying degrees of thermal expansion coefficients, hardness, and compatibility with coatings. If the difference in thermal expansion coefficient between the substrate and the coating is too large, during temperature changes, significant internal stress will be generated between the two due to inconsistent thermal expansion and contraction, which can easily lead to coating peeling. For example, when coating ceramic coatings on certain aluminum alloy substrates, due to the significant difference in thermal expansion coefficients between the two, the coatings are prone to cracking and peeling due to thermal stress during use, which affects their service life.
Performance factors of the coating itself
The temperature resistance level of the coating: Obviously, the higher the temperature resistance level of the coating, the longer it can maintain stable performance in high temperature environments. For example, ceramic coatings with a temperature resistance of 1200 ℃ are more resistant to high temperatures in high-temperature furnaces than organic coatings with a temperature resistance of 800 ℃. Under the same high-temperature conditions, the service life of the former often exceeds that of the latter.
Density of coatings: Coatings with good density can better block the corrosion of the substrate by external environmental factors, prevent corrosive media, oxygen, etc. from penetrating the coating and coming into contact with the substrate. Coatings prepared by physical vapor deposition have higher density and can effectively protect the substrate under the same environment compared to some thermal spray coatings with higher porosity, resulting in a longer service life.
Coating adhesion: The adhesion between the coating and the substrate, as well as between the layers of the coating, is strong, making it less likely for the coating to peel off or delaminate during use. For example, after special surface pretreatment and the use of appropriate adhesives to improve adhesion, the coating can still firmly adhere to the substrate under high temperature, external impact and other conditions, thus ensuring its longer service life.
Construction process factors
Surface pretreatment quality: Pre treatment work such as oil removal, rust removal, and cleaning of the substrate surface is crucial before coating. If there are still impurities such as oil stains and rust on the surface, it will seriously affect the adhesion between the coating and the substrate, making the coating prone to peeling and falling off in the early stages of use, greatly shortening its service life. For example, if the rust on the surface of the steel substrate is not completely removed before coating construction, the coating will quickly be damaged due to poor adhesion in subsequent use.
Coating thickness: Coating thickness that does not meet the requirements during construction can also affect its lifespan. The coating is too thin, which may not provide sufficient protection and is easily damaged by factors such as high temperature and corrosion; However, if the coating is too thick, internal stress is prone to accumulate, which may lead to coating cracking and peeling. For example, the thickness of the organic silicon high-temperature resistant coating should be 100-150 μ m. If the coating thickness is only 50 μ m, it will be difficult to effectively resist high temperature and corrosion, and the service life will be significantly shortened.
Curing process: Different high-temperature resistant coatings need to be cured according to specific curing conditions (such as temperature, time, etc.) to fully crosslink the coating and form a stable structure. If the curing temperature and time are not sufficient, the performance of the coating may not reach its optimal state, and problems such as softening and decreased adhesion may occur during use, affecting its service life. For example, a certain epoxy high-temperature resistant coating needs to be baked at 180 ℃ for 2 hours for curing. If the baking temperature or time does not meet the standard, the coating is prone to failure in subsequent high-temperature environments.

Room termperature curing polysilazane, pls check IOTA 9150, IOTA 9150K. 
High termperature curing polysilazane, pls check IOTA 9108, IOTA 9118.