摘 要：针对传统永磁体式/含液冷永磁体型电磁超声换能器（EMAT）体积大、永磁体高温易消磁及难以持续耐高温检测等问题，提出了一种可用于高温持久在线监测的Laser-仅线圈式表面波（RW）EMAT检测方法。建立了基于表面约束机制的铝合金Laser-仅线圈式RW EMAT检测过程的场路耦合分析有限元模型，采用正交试验法，分析了仅线圈式RW EMAT励磁线圈等关键设计参数对RW检测幅值和波包宽度的影响，据此获取了仅线圈式RW EMAT最佳设计参数组合并进行了试验验证。研制了Laser-仅线圈式RW EMAT及其励磁电路，并进行了20~400 ℃高温铝合金RW检测实验。结果表明，接收线圈（曲折线圈）的导线分裂数和线圈匝数分别对仅线圈式RW EMAT接收信号幅值和波包宽度起主要影响。优化后的仅线圈式RW EMAT接收幅值提高1.67倍，且能在400 ℃高温铝合金试样上捕获到稳定RW信号，证明了其可靠高温检测能力。

Abstract: Aiming at the problems of traditional permanent magnet or liquid-cooled permanent magnet type elec-tromagnetic acoustic transducer (EMAT), such as large volume, easy demagnetization of permanent magnet at high temperature and difficulty in sustained high temperature detection, a Laser-coil only Rayleigh wave (RW) EMAT de-tection method for high temperature sustained on-line monitoring is proposed. A finite element model for field-circuit coupling analysis of the aluminum alloy Laser-coil only RW EMAT detection process based on the surface constraint mechanism has been established, and the effects of key design parameters such as the excitation coil of the coil-only RW EMAT on the amplitude and wave packet width of the RW detection have been analyzed by using orthogo-nal experimental method, according to which the optimal design parameter combinations of the coil-only RW EMAT was obtained and verified by experiments. A Laser-coil only RW EMAT and its excitation circuit were developed, and RW detection experiments on high-temperature aluminum alloys from 20 to 400 ℃ were carried out. The results show that the number of wire splitting and coil turns of the receiving coil (meander coil) have a major influence on the received signal amplitude and wave packet width of the coil-only RW EMAT, respectively. The receiving amplitude of the optimized coil-only RW EMAT is increased by 1.67 times, and the stable RW signal can be captured on the 400 °C high temperature aluminum alloy sample, which proves its reliable high temperature detection capability.