喷射型3D打印磷酸镁水泥基材料电磁防护性能研究

Electromagnetic protection are highly demanded in the security fields of medical, information, health and military. Cement based materials that are endowed with electromagnetic absorbing functions can be coated on the construction surface to achieve the rapidly electromagnetic protection goals. The traditional cement based materials with the function of electromagnetic protection can hardly meet the design requirements of wide frequency regions, high absorbing ability and excellent bonding property at the same time, which greatly decrease the electromagnetic protection effect and its application prospect. Based on the characteristics of high early strength and excellent bonding strength of magnesium phosphate cement, combined with nano ferrite absorbing materials, low density porous wave-transmitting materials and metakaolin like performance regulating materials, sprayed 3D printing magnesium phosphate cement with the function of electromagnetic protection (MPC-EA) has been developed in this project. The optimization and evaluation methods of MPC-EA are proposed according to the studies of the pumping, spraying and constructing properties of the material. The variation patterns and influencing factors of electromagnetic absorbing and mechanical properties of MPC-EA are studied, and the reaction mechanism of electromagnetic performance of MPC-EA is proposed. With optimization of the electromagnetic performance of MPC-EA in each layers, functionally graded MPC-EA composite structure with gradually changing impedance is developed. The principle of optimal design and reliability evaluation method of electromagnetic protection of MPC-EA are established. This project has important theoretical value and practical significance on the electromagnetic protection of civil and military fields.

医疗、信息、健康和军防安全等领域对电磁防护有重大需求，赋予水泥基材料电磁吸波功能并涂覆建筑结构表层可达到对其快速电磁防护的目的。传统水泥基电磁防护材料很难同时满足宽频段、高吸收和高粘结的设计要求，影响其电磁防护效果和应用前景。项目利用磷酸镁水泥快硬早强、高粘结特性，通过复合纳米铁氧体吸波材料、轻质多孔透波材料和偏高岭土性能调节材料，研发适用于喷射型3D打印具有电磁吸波功能的磷酸镁水泥基材料（MPC-EA）。研究MPC-EA的可压送性、可喷出性和可建造性，提出MPC-EA可打印性优化与评估方法；研究喷射3D打印MPC-EA吸波效能和力学性能的变化规律及其影响因素，提出MPC-EA电磁性能和凝结硬化反应机理；优化不同打印层材料电磁性能，研制阻抗渐变的功能梯度MPC-EA复合结构，建立MPC-EA电磁防护的优化设计原理及其可靠性评价方法。项目在民用和军用电磁防护领域具有重要理论价值与实践意义。

建筑电磁防护采用人工涂敷水泥基电磁吸波材料，存在精度低、效率低、电磁防护效果差等问题。项目自主研制了可喷射3D打印型水泥基电磁吸波材料，揭示了设备参数对水泥基材料打印性能的影响规律，建立了喷射3D打印水泥基材料优化评估方法。采用水含量分析方法、CT切片扫描技术以及微观形貌表征方法，揭示了喷射3D打印水泥基材料的凝结硬化机理。基于最大阻抗匹配和电磁吸波机理，建立了水泥基电磁吸波材料与结构一体化设计方法，有效解决了传统电磁吸波材料单一阻抗匹配频带窄、效能低等问题。项目成果丰富了电磁防护工程建造方法，为喷射3D打印技术性能评估、力学性能提升机理分析以及电磁吸波结构设计提供了技术支撑和理论支撑。