What are the advantages of polysilazane?

1. Introduction

With the rapid development of advanced materials technology, the requirements for coating materials are no longer limited to achieving a single function. Instead, they pursue perfect integration with a variety of substrates and long-term stability under complex working conditions. Polysilazane, thanks to its unique molecular structure and chemical properties, exhibits excellent substrate compatibility. This compatibility stems not only from its physical and chemical properties, but also from its ability to interact with the substrate surface, forming a strong bond. In-depth research on the compatibility of polysilazane with different substrates is crucial for expanding its application and promoting technological upgrades in related industries.

2. Compatibility Mechanism 

The substrate compatibility of polysilazane can be understood by its interaction with two major types of substrates.

First, with respect to metal substrates, polysilazane exhibits universal and strong bonding capabilities. Its compatibility covers a wide range of substrates, including carbon steel, stainless steel, cast iron, aluminum alloys, titanium alloys, and various high-temperature alloy steels. The root of this excellent adhesion lies in its active chemical bonding ability. The silicon-nitrogen bonds within the polysilazane molecular chain react chemically with reactive groups such as hydroxyl groups, naturally present on metal surfaces or generated through pretreatment, forming stable silicon-oxygen-metal covalent bonds at the interface. This chemical bond is far stronger than conventional physical adsorption, providing a solid foundation for the coating, enabling it to effectively protect metal substrates from high-temperature oxidation, electrochemical corrosion, and other forms of chemical attack.

Furthermore, polysilazane also exhibits excellent compatibility with non-metallic substrates. Through its excellent wettability and interfacial reactions, polysilazane forms a strong bond with surfaces ranging from glass-ceramics to structural ceramics to cementitious products. It not only forms a continuous, complete protective film on smooth, dense surfaces, but also effectively penetrates and anchors into porous cementitious substrates. This imparts excellent high-temperature, corrosion, and aging resistance to various non-metallic materials, significantly broadening its application range.

3. Synergistic Effects 

The strength of polysilazanes lies not only in their direct interaction with substrates but also in their ability to serve as a key component in more complex coating systems, creating synergistic effects with other materials.

First, their compatibility with organic resin coatings. Polysilazanes are well-matched with a variety of common industrial resins, such as epoxy resins, amino resins, and silicone resins, as well as stoving coating materials. In practical applications, a polysilazane conversion coating is often first formed on the substrate surface through spraying, dipping, or other methods. This base film not only provides its own protective properties but, more importantly, does not negatively impact the adhesion and impact resistance of subsequently applied topcoats, such as epoxy, amino, or silicone coatings. In some cases, it even enhances their properties, optimizing the overall performance of the coating system.

Second, their compatibility with other coating materials. Polysilazanes offer exceptional formulation flexibility, allowing for physical blending or chemical modification with a variety of other resin film-forming agents and various functional additives. A typical example is its hybridization with polymethyl methacrylate. Through this molecular-level design, the resulting hybrid coating successfully balances the inherent high density and excellent corrosion resistance of polysilazane with the superior optical transmittance and excellent bonding properties of PMMA, meeting the demanding requirements of specialized applications such as optical devices and flexible electronic packaging.

4. Applications

Due to its excellent substrate compatibility and system synergy, polysilazane has played an irreplaceable role in numerous high-tech fields.

4.1 In the aerospace industry

Its ability to withstand extreme environments is crucial. Polysilazane coatings provide reliable protection for hot-end components of aircraft engines, thermal protection systems for rockets, and various spacecraft structures. For example, SiCN ceramic coatings, formed by the decomposition of polysilazane under specific conditions, possess a dense microstructure and stable chemical properties, capable of withstanding transient ultra-high temperatures exceeding 3.000°C. Consequently, they are widely used for surface protection of critical components such as aircraft engine turbine blades, effectively extending their service life.

4.2 In the electronics field

Its application has penetrated into cutting-edge manufacturing processes. In the production of chips with a manufacturing process of 5 nanometers and above, polysilazane is used as a high-performance insulating layer material. The key lies in its ability to achieve effective electromagnetic shielding at the nanometer-thin level, safeguarding the integrity of the chip's internal signals. It also plays a vital role in flexible organic electronic packaging, forming a strong barrier against moisture, oxygen, and dust, protecting delicate electronic components from environmental damage.

4.3 In the photovoltaic field

Its long-term protective effect is remarkable. Photovoltaic panels treated with polysilazane coatings significantly improve their weather resistance and durability. Tests have shown that after a thermal shock test involving 24 hours of exposure to 800 degrees Celsius and immediate water cooling, the coating surface remained intact, showing no discoloration, cracking, or peeling. Its weather resistance is more than three times that of traditional protective materials, providing a strong guarantee for the long-term and stable operation of photovoltaic power plants.

4.4 In the construction sector

Its versatility is fully utilized. When applied to building exteriors, it forms a highly weather-resistant protective coating, significantly improving the substrate's resistance to UV radiation and aging, thereby extending the lifespan of the building's facade. It can also be used as a hydrophobic coating for architectural glass, imparting durable and excellent hydrophobic properties to the glass surface, making it easier to clean and maintain daily while maintaining clear vision even on rainy days.

4.5 In the marine engineering sector

Its environmentally friendly properties and long-lasting antifouling capabilities are highly sought after. Low-surface-energy antifouling paints based on polysilazane are applied to marine structures such as ship hulls and deep-sea drilling platforms. They effectively inhibit the attachment of marine organisms such as barnacles and algae, maintaining their antifouling effects for up to five years, eliminating the need for dry docking for cleaning. Notably, these coatings are even more environmentally friendly, with the slow-release rate of antifouling agents, such as copper ions, precisely controlled to below four micrograms per square centimeter per day, fully meeting the stringent requirements of the International Maritime Organization's Anti-fouling Systems Convention.

5. Summary

Polysilazane, with its unique molecular structure as its cornerstone, possesses strong compatibility with a wide range of substrates. Whether universally compatible with metal substrates or well-suited for non-metallic substrates, it demonstrates its exceptional performance in material adaptation. Looking ahead, with the continued advancement of materials science research and continuous innovation in industrial technology, polysilazane is expected to emerge in even more emerging fields.