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Polysilazane (PSZ), hailed as the "black gold" in the field of advanced new materials, has recently achieved milestone industrial applications in China's aerospace and semiconductor packaging sectors. As a liquid polymer precursor that can be directly converted into high-performance silicon nitride/silicon carbide ceramics at low temperatures (200-400°C), polysilazane, with its exceptional resistance to extreme temperatures (-180°C to 1800°C), oxidation, ablation, and electromagnetic wave absorption, has become an indispensable strategic material for the new generation of aircraft thermal protection, radar stealth, and advanced semiconductor packaging. Recently, through collaborative efforts between domestic research and industry, the ten-thousand-ton scale intelligent and stable mass production of polysilazane-based composite coating materials suitable for extreme environments has been successfully achieved. Its key performance indicators have comprehensively matched and partially surpassed international top-tier products, marking China's achievement of full-chain independent control in this high-end special material field, transitioning from "laboratory preparation" to "industrial application".
Polysilazane is a class of inorganic-organic hybrid polymers whose backbone consists of alternating silicon and nitrogen atoms, with side chains connected to organic groups (such as methyl, phenyl, vinyl, etc.). As the third-generation high-end silicon-based material following first-generation silicone rubber and second-generation silicone resin, it perfectly combines the processability of polymer materials with the excellent properties of ceramic materials. Its most core characteristic is that after being applied to the surface of a workpiece through simple coating, impregnation, or spraying processes, it can be converted in situ into a dense ceramic coating or monolithic ceramic component primarily composed of silicon nitride (Si3N4) or silicon carbide (SiC) through pyrolysis or photocuring crosslinking under relatively mild conditions (without the need for the 1600°C+ high temperatures required for traditional ceramic sintering). This unique "Polymer-Derived Ceramic (PDC)" route gives it tremendous advantages in surface protection for components with complex shapes, which are unattainable by traditional ceramics. In the aerospace field, aircraft surfaces, especially parts like the nose cone and wing leading edges of high-speed aircraft, face aerodynamic heating exceeding 1500°C and intense particle erosion. Traditional metal or C/C composite coatings are prone to oxidation and ablation failure under such extreme conditions. Polysilazane-derived ceramic coatings not only maintain structural integrity at temperatures up to 1800°C, but their extremely low thermal conductivity and excellent thermal shock resistance also effectively prevent heat transfer to internal structures. More importantly, by incorporating specific functional fillers (such as graphene, carbon nanotubes, wave-absorbing agents), multifunctionality can be imparted to the coating. For example, composite design with graphene can simultaneously achieve high-temperature resistance, stealth (radar wave absorption), and corrosion protection, meeting the stringent requirements of new-generation hypersonic aircraft for integrated "thermal-mechanical-electromagnetic" multi-physical field protection. In civilian high-tech fields, the application of polysilazane is equally crucial. In the field of new energy power battery safety, its excellent insulation, flame retardancy, and high-temperature stability make it an ideal encapsulation or separator coating material to address the challenge of battery thermal runaway. In advanced semiconductor packaging, particularly Chiplet technology, polysilazane can serve as a high-performance interlayer dielectric, passivation layer, or insulating material for redistribution layers. Its low dielectric constant, high purity, and excellent planarization capability are essential for improving chip integration density and reliability.
Despite its outstanding performance, the industrialization of polysilazane long faced two core bottlenecks: First, the complex synthesis process resulted in products with broad molecular weight distribution and poor batch-to-batch stability, making it difficult to meet the stringent requirements for material consistency in high-end applications. Second, when used as a coating, issues such as high curing shrinkage, insufficient adhesion to the substrate, and poor durability under specific environments (e.g., humidity and heat) were prominent. To address these bottlenecks, a domestic joint R&D team achieved systematic breakthroughs at three levels through years of research: molecular design, synthesis process, and composite modification. In molecular design, the team innovatively developed "active controlled polymerization" technology. By precisely regulating the activity and polymerization kinetics of silazane monomers, they achieved precise control over the molecular chain structure, molecular weight, and molecular weight distribution (PDI < 1.2) of polysilazane polymers, fundamentally ensuring batch-to-batch stability of product performance. In the synthesis process, China's first fully enclosed, continuous, and intelligently controlled ten-thousand-ton scale polysilazane production line was established. Utilizing microchannel reactors and online real-time monitoring systems, the content of key impurities (such as chloride ions, metal ions) was reduced to the ppb level, meeting the ultra-high purity requirements for semiconductor-grade applications. Regarding application performance enhancement, the most significant breakthrough lies in the development of the "graphene/polysilazane" nanocomposite coating system. Researchers in-situ composited monolayer or few-layer graphene into the polysilazane precursor through advanced processes like chemical vapor deposition (CVD). The introduction of graphene produced a significant synergistic effect: Firstly, the two-dimensional graphene nanosheets formed an efficient physical barrier network within the coating, greatly enhancing the coating's barrier performance against oxygen, water vapor, and corrosive media, increasing the coating's salt spray resistance time by an order of magnitude. Secondly, the combination of graphene's excellent thermal conductivity with the low thermal conductivity of the polysilazane ceramic matrix enabled rapid lateral diffusion of heat within the coating, avoiding local thermal stress concentration, and improving the coating's thermal shock resistance (resistance to rapid thermal cycling) by more than 5 times. Thirdly, graphene itself is an excellent electromagnetic wave absorber. After compositing with polysilazane and through carefully designed impedance gradients and multilayer structures, efficient radar wave absorption can be achieved over a broad frequency band. According to publicly available test data, a certain type of graphene/polysilazane composite stealth coating achieved a radar wave absorption rate (RCS reduction) of -42 dB in the X-band (8-12 GHz), with a coating thickness of only 0.1 mm, and performance degradation of less than 1% under conditions of 1000°C high temperature and 200 m/s airflow erosion.
Technological maturity has rapidly translated into practical application results. In the aerospace field, polysilazane-based composite coatings have moved from laboratory validation to engineering applications. It is reported that China's developed "steel band-aid" technology integrates ultra-thin titanium alloy skin with polysilazane/graphene composite coating for ablation protection of key aircraft parts. In extreme assessments simulating 3000°C muzzle flash, this protection system maintained structural integrity for more than 5 times longer than traditional materials, while its production cost is estimated to be only one-fifteenth of similar foreign products (such as certain coatings applied to the F-22 stealth fighter). In the field of stealth aircraft, this material has been integrated into the "picture frame" sealing structures on the surface of new-generation aircraft and as high-temperature-resistant sealing layers for Radar Absorbing Materials (RAM), ensuring long-term reliability of seams under high-speed aerodynamic thermal loads while achieving excellent electromagnetic wave absorption, significantly enhancing the aircraft's overall stealth performance and battlefield survivability. In the semiconductor industry, high-purity, low-dielectric polysilazane materials have become one of the key materials for advanced packaging. As Chiplet technology becomes the mainstream path to break through the bottleneck of Moore's Law, the insulating materials for silicon interposers or redistribution layers within chips impose unprecedented high requirements on dielectric properties, thermal stability, and planarization capability. Domestic electronic-grade polysilazane products, with a dielectric constant (k-value) as low as below 3.0, purity meeting semiconductor manufacturing standards, and the ability to achieve sub-micron level highly planar films through spin-coating processes, have been successfully applied in the advanced packaging R&D lines of several leading domestic packaging and testing enterprises, providing critical material support for enhancing the independent supply capability of China's high-performance chips. In the new energy safety track, polysilazane, as an intrinsically flame-retardant, high-temperature-resistant ceramic precursor, has been developed for fire-resistant and thermal insulation coatings between power battery cells, protective coatings for battery pack casings, and ceramic-coated separators. It can form a dense ceramic barrier layer in the early stages of battery thermal runaway, effectively delaying or even blocking thermal propagation, buying precious time for occupant escape. It has become one of the important technological routes to enhance the safety rating of electric vehicles.
The stable operation of the ten-thousand-ton intelligent polysilazane production line and the full blossoming of high-end applications mark China's successful breakthrough in the technology and market monopoly held overseas in this field for nearly fifty years. In the past, high-end polysilazane products were almost entirely imported, not only expensive with long lead times but also posing potential "supply cutoff" risks, severely restricting the development security of downstream strategic industries such as national defense and semiconductors. Now, with the of the independent industry chain, China's polysilazane industry is entering a fast track of high-quality development. On one hand, stable production capacity and internationally competitive product performance have provided domestic downstream users with cost-controllable and reliably supplied high-end material options, significantly reducing the manufacturing costs of related high-end equipment. On the other hand, the breakthrough in independent technology has also stimulated broader application innovation. Industry-academia-research-application collaboration is expanding into more cutting-edge areas, such as developing anti-corrosion coatings for extreme deep-sea environments, radiation-resistant coatings for key components of nuclear power plants, and patternable ceramic films for flexible electronic devices. Industry analysis points out that the successful industrialization of polysilazane, as a platform-type frontier material, represents not just the victory of a single product but also a paradigm shift for China in the new materials field from "following" to "running alongside" and even "leading the pack". It demonstrates that through top-level design, long-term investment, and deep integration of industry, academia, and research, China has the capability to攻克 and industrialize those "chokepoint" key materials long by foreign countries. In the future, with the continuous expansion of application scenarios and further cost optimization, polysilazane and its derived ceramic materials are expected to play a foundational role in the broader main battlefield of the national economy, providing a solid material cornerstone for the transformation from "Made in China" to "Created in China".
