Polysilazane refers to a class of high-molecular-weight compounds featuring a silicon-nitrogen (Si–N) backbone. Owing to the relatively high bond energy of the Si–N bond, polysilazane materials exhibit notable advantages in high-temperature resistance, and research and applications in the fields of high-temperature coatings and ceramic precursors have continued to deepen in recent years.

In high-temperature coating applications, polysilazane can be applied to the surface of metals, ceramics, or composite substrates and subsequently pyrolyzed to form ceramic coatings containing silicon carbonitride (SiCN) or silicon carbide (SiC). Such coatings provide oxidation and corrosion protection in high-temperature environments, making them suitable for aerospace engine components, gas turbine blades, and high-temperature furnace equipment, among others. Compared to conventional organic coatings, polysilazane-derived coatings demonstrate superior high-temperature stability and can retard the thermal degradation of substrate materials to a certain extent.

As a ceramic precursor, the curing and conversion mechanisms of polysilazane have been systematically studied. Upon heating to temperatures between 800°C and 1200°C in an inert or ammonia atmosphere, polysilazane undergoes pyrolysis, with organic groups progressively eliminated to form amorphous or microcrystalline ceramic phases. This process offers a viable route for fabricating ceramic components with complex geometries, and is particularly suitable for producing fiber-reinforced ceramic matrix composites using the infiltration-pyrolysis method.

One current focus of technological development is reducing the curing and pyrolysis temperatures. Excessively high processing temperatures increase energy consumption and impose limitations on certain heat-sensitive substrates, making the development of low-temperature conversion processes of practical significance. In addition, optimizing coating-to-substrate adhesion remains a research priority—through molecular structure modification or the introduction of coupling agents, the durability of adhesion under thermal cycling conditions can be improved.

In terms of application expansion, polysilazane also demonstrates potential in optical coatings. After curing, the resulting coatings exhibit good transparency and surface hardness, making them suitable for the protection and hardening treatment of optical components. As preparation techniques mature and costs gradually decrease, polysilazane materials are expected to gain adoption in a broader range of high-temperature and specialty application scenarios.

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