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With the continuous development of the aerospace field, the service conditions of high temperature structural components such as metal and carbon materials are increasingly harsh. The service life of high temperature structural components can be effectively improved by preparing silicon-based ceramic coatings on the surface of high temperature structural components and giving them special properties through appropriate processes. In recent years, the polymer precursors conversion ceramic coating has gradually become a novel method for preparing inorganic coatings. The new approach has the advantage of excellent processability and functional scalability, which gets more and more attention from researchers. The research progress of high temperature resistant ceramic coatings based on silicon-containing polymeric precursors was reviewed in this paper. Firstly, the preparation of ceramic coatings from the polymers was introduced, including the influences of silicon-based polymer precursors, fillers, coating and pyrolysis process on the structure and properties of the obtained coatings. Then, the applications of polymer-derived ceramic coatings in high temperature protection fields, such as anti-oxidation, environmental barrier and thermal barrier coatings were discussed. Finally, The problems in improving coating performance and defect control of polymer ceramic coatings were pointed out, and the development direction of polymer ceramic coatings was prospected, for example, by introducing ultra-high temperature elements such as Hf, Zr, Ta into silicon-based precursors, improving the temperature resistance level of ceramic coatings, and developing new efficient ceramic technology to improve the existing efficiency and applicability.

为开发工业制备纳米乳液新技术，通过仿真实验分析在槽式超声反应器中引入微纳米气泡对声场强度和分布的影响。以花生油为油相，吐温80和司盘80为乳化剂，在乳化过程中采用基于微纳米气泡强化的槽式超声反应器制备纳米乳液。利用正交实验探索了超声时间、进气量、复合乳化剂添加量对纳米乳液平均粒径与多分散指数的影响，并优化了纳米乳液制备条件。结果表明：加入适量微纳米气泡会提高声场强度和分布均匀性；制备纳米乳液的最优条件为超声时间12 min、进气量150 mL/min、复合乳化剂添加量3%（以水的体积计），在此条件下乳液平均粒径为190.9 nm，多分散指数为0.178，较未加入微纳米气泡所制备乳液的平均粒径减小73.3%，且表现出更好的动力学稳定性。该方法制备的纳米乳液平均粒径和多分散指数均较小，且具有快速、体量大、成本低的生产优势。 In order to develop new technologies for industrial preparation of nanoemulsion, the effects of introducing micro-nano bubbles in the trough ultrasonic reactor on the intensity and distribution of the sound field were analyzed through simulation experiment. With peanut oil as oil phase, Tween 80 and Span 80 as emulsifiers, and nanoemulsion was prepared in trough ultrasonic reactor based on micro-nano bubble strengthening in the emulsification process. The effects of ultrasonic time, air intake, dosage of compound emulsifier on the average particle size and polydispersity index of nanoemulsion were investigated by orthogonal experiment, and the preparation conditions of nanoemulsion were optimized. The results showed that adding an appropriate amount of micro-nano bubbles could improve the sound field intensity and uniformity of distribution. The optimal conditions for preparation of nanoemulsion were obtained as follows: ultrasonic time 12 min, air intake 150 mL/min, dosage of compound emulsifier 3%(based on the water volume). Under these conditions, the average particle size of the nanoemulsion was 1909 nm, and the polydispersity index was 0.178. The average particle size of the nanoemulsion was reduced by 73.3% than that without micro-nano bubble, and showed better dynamic stability. The average particle size and polydispersity index of the nanoemulsion prepared by this method are small, and the method has advantages of rapid preparation, large volume, and low cost.

The polymer precursor derived ceramics route is one of the important ways for the preparation of ceramics, and pyrolysis is absolutely necessary in the process. The traditional thermal pyrolysis suffers from slow heating/cooling rate, long processing time, and high energy consumption. In recent years, new technologies, including laser pyrolysis, microwave treatment, and discharge plasma sintering, have attracted the attention in the researchers due to the advantages of fast heating/cooling rate and low energy consumption. This paper summarizes the research progress in rapid pyrolysis in PDCs. The advantages of the new technologies in the preparation of high-performance ceramics are also discussed. [ABSTRACT FROM AUTHOR]