SBIR Phase I: Novel Environmental Barrier Coatings for High-Temperature Metals and Ceramic Matrix Composites

这个小型企业创新研究第一阶段项目提出了两种方法来开发用于SiC基陶瓷复合材料和耐火材料以及其他高温金属合金的薄，低成本保护涂层，达到1200 C。 金属和陶瓷需要保护涂层，以防止氧化和腐蚀引起的加速疲劳。 通过对热固性聚硅氮烷进行金属掺杂，可以制备出体积收缩率低、结合强度高、气密性好的新型SiCN涂层。 Zr/Ti和Zr/Al掺杂的聚硅氮烷将被粉末涂覆，从而通过限制挥发物含量来增加陶瓷产率。 掺杂的SiCN涂层提供较低的杨氏模量和可定制的热膨胀系数（TCE）和表面化学性质，提高了涂层在热循环过程中的耐久性。 第二个提出的涂层系统涉及溶胶-凝胶或聚合物衍生的ZrSiO 4氧气屏障与溶胶-玻璃顶层的水分保护。 锆英石作为Y-Zr-Al-Si-O保护层的粘结层。 锆石相将通过标准溶胶合成进行旋转/浸渍浇铸，或者衍生自Zr和Si热固性聚合物的缩合。 该涂层的应用不仅限于保护SiC基陶瓷复合材料，还可用于氮化硅、硅基整体陶瓷和高温金属合金。该计划更广泛的影响/商业潜力涉及创新材料解决方案，以提高推进和发电热力发动机中金属，陶瓷和复合材料部件的性能，耐用性和预期寿命。 热循环和加速腐蚀大大缩短了高温材料的使用寿命，这些材料正在经历越来越苛刻的工作条件。 在高温条件下保护陶瓷和金属部件已被确定为21世纪世纪材料科学的重点。 目前用于金属和陶瓷的保护涂层由不同成分的材料的厚层（数百微米）组成，增加了用于长寿命应用的高温材料的生产的复杂性和成本。 通过创新的化学方法，使用低成本、易加工的材料实现这一目标，将降低过高的腐蚀成本。 正在开发的涂层方法通过涂层系统的重新应用提供了快速检查和维修的可能性。 陶瓷、金属和复合结构材料在腐蚀性或氧化性环境中的高热机械载荷下工作，将受益于有待开发的低成本涂层系统。

This Small Business Innovation Research Phase I project proposes two approaches to develop a thin, low cost, protective coating for SiC-based ceramic composites and refractory and other high-temperature metal alloys reaching 1200 C. Protective coatings are required for metals and ceramics to prevent accelerated fatigue from oxidation and corrosion. A novel SiCN coating will be synthesized via metal doping of thermoset polysilazanes, exhibiting low volumetric shrinkage, high bond strength, and excellent hermiticity. Zr/Ti and Zr/Al doped polysilazanes will be powder coated, thereby increasing ceramic yield by limiting volatile content. Doped SiCN coatings offer lower Young's modulus and tailorable coefficients of thermal expansion (TCEs) and surface chemistries, increasing the coatings' durability during thermal cycling. The second proposed coating system involves a sol-gel or polymer derived ZrSiO4 oxygen barrier with a sol-glass top layer for moisture protection. Zircon functions as a bond coat for the protective Y-Zr-Al-Si-O. The zircon phase will either be spin/dip cast via a standard sol synthesis or derived from the condensation of Zr and Si thermoset polymers. The applications of the novel coatings in this proposal are not limited to protecting SiC-based ceramic composites, but also can be used for silicon nitride, silicon-based monolithic ceramics, and high-temperature metal alloys. The broader impact/commercial potential of this program involves innovative material solutions to improve the performance, durability, and life expectancy of metal, ceramic, and composite components within propulsion and power generation heat engines. Thermal cycling and accelerated corrosion dramatically reduce the lifetime of high-temperature materials, which are experiencing increasingly harsh operating conditions. Protecting ceramic and metal components during service in elevated temperature regimes has been identified as a 21st century materials science priority. Current protective coatings for both metals and ceramics consist of thick layers (100s of microns) of materials of varying composition, increasing the complexity and cost of production of high-temperature materials intended for long-lifetime applications. Achieving this with low-cost, easily processable materials through innovative chemistry will reduce the exorbitant costs of corrosion. The coating approaches being developed offer the potential for quick inspection and servicing through reapplication of the coating system. Ceramic, metal, and composite structural materials operating under high thermo-mechanical loads in corrosive or oxidative environments would benefit from the low-cost coating systems to be developed.