等离子喷涂MoSi2/Al2O3高温吸波涂层介电常数的温度响应规律研究

The high-temperature microwave-absorbing coating by plasma spraying is one of the key materials for new generation fightersto implement the radar stealth, especially for the heat parts. But currently, the investigation of high-temperature microwave-absorbing coatings is trapped, because we don’t know how the dielectric constant to vary with the changing temperature, let alone the exact dielectric constant at high temperatures. The heat microwave-absorbing properties of the coatings designed from the room temperature dielectric constants are greatly different from the expected, which means that those design results are of no value. The temperature response mechanism of the dielectric constant was ever studied on the pressed block composite materials and composites with long fibers, which can’t be directly applied on the coatings by plasma spraying because of different material system, different preparation process and different microstructure. Therefore, the study of the plasma spraying coatings for application is focused on the temperature response mechanism of the dielectric constant. This project investigates the typical MoSi2/Al2O3 microwave-absorbing coatings by plasma spraying, where the temperature response of the dielectric constant, the influences of absorbent size, absorbent morphology and absorbent dispersion state and also effects of process temperature, process atmosphere, process rate and other factorson the temperature response of the dielectric constant will be studied. The results will be very essential for the design of high-performance microwave-absorbing coatings at high temperatures.

等离子喷涂高温吸波涂层是实现武器装备高温部位雷达隐身的关键材料之一。但目前在涂层高温吸波性能的研究中遇到了很大困难，其最重要的原因就是对涂层介电常数的温度响应规律、尤其是高温下的介电常数仍不清楚，采用常温介电常数设计的吸波涂层，其高温吸波性能与设计结果相差很大，设计结果基本没有价值。虽然已有人对压制块体复合材料和长纤维复合材料的介电常数温度响应进行过研究，但由于这些材料的材料体系、制备过程和显微结构与等离子喷涂吸波涂层相差很大，其规律无法直接用于等离子喷涂吸波涂层。因此，对介电常数温度响应规律认识的欠缺是目前制约等离子喷涂高温吸波涂层研究和应用的主要瓶颈。本申请项目拟以典型等离子喷涂MoSi2/Al2O3吸波涂层为对象，研究涂层的介电常数温度响应规律，认识吸收剂尺寸、形态和分散状态以及涂层形成过程的温度、气氛、速率等因素对涂层介电常数温度响应的影响规律，为设计高性能高温吸波涂层提供依据。

等离子喷涂高温吸波涂层是实现武器装备高温部位雷达隐身的关键材料之一。但由于对涂层介电常数的温度响应规律、尤其是高温下的介电常数仍不清楚，使得介电常数温度响应规律认识的欠缺成为目前制约等离子喷涂高温吸波涂层研究和应用的主要瓶颈。因此，本申请项目以典型等离子喷MoSi2/Al2O3吸波涂层为对象，研究涂层的介电常数温度响应规律，认识吸收剂尺寸、形态和分散状态以及涂层形成过程的温度、气氛、速率等因素对涂层介电常数温度响应的影响规律，为设计高性能高温吸波涂层提供依据。