Identification and characterisation of steel corrosion using passive high frequency RFID sensors

High frequency RFID sensors are attractive in diverse applications where sensor performance is required at a low cost and dimension restriction. An approach adapting commercial passive 13.56 MHz RFID tags has been developed for sensing corrosion stage. This investigation includes balance of sensing and positioning of RFID sensors for corrosion detection by analysing real and imaginary parts of the complex impedance. With passive HF RFID sensors, real part and imaginary part of complex impedance have been extracted from the reader coil with VNA (vector network analyser) and delivering a unique capability for corrosion sensing with different atmospheric exposure time steel samples (1 month, 6 months, 10 months and 12 months). With different positioning (5–25 mm), features extraction based on the complex impedance with PCA (principal component analysis) has been designed for position-independent corrosion evaluation.     

Synthesis of Quaternary,Long-Chain N-Alkyl Amides and Their Corrosion Inhibition in Acidic Media

New cationic surfactants were synthesized by the quaternization of a number of straight-chain amide derivatives with triethylamine or pyridine. The corrosion inhibition tests of the surface-active compounds were performed at room temperature for 24 h on carbon steel coupons in acidic media using the gravimetric method. The acidic media used were 1.5 M HCl and 1.5 M H₂SO₄. Almost all of the synthesized cationic surfactants showed efficient inhibition of corrosion in the test. To establish the inhibition efficiencies of the inhibitors, surface characterization studies (contact angle measurements, SEM analysis and optical profilometer images) of the metal coupons used were performed.     

7xxx系铝合金热处理的进展

7xxx系合金是基于Al-Zn-Mg（-Cu）系的可热处理的锻铝合金，广泛应用于高性能航空结构和运输部件。除了受成分、铸造和形变热处理影响外，材料性能的平衡明显受到其所经历的热处理方式的影响。描述了均匀化、固溶处理、淬火、时效对7xxx系高强合金组织和性能的影响。总结了在Monash大学进行的有关厚板产品的生产工艺，包括从均匀化到最终的时效处理，以及通过控制微观组织特征，比如弥散体、粗粒子、精细析出相、晶粒结构和晶界特征，来实现组织与性能的平衡。重点陈述了相关方法，如通过高温热处理溶解不需要的粗粒子、基于连续冷却析出行为的淬火敏感性变化、通过实验与建模来研究时效包括一步时效、两步时效、三步时效。对每种情况下的组织与性能都进行研究。     

904L(N08904)不锈钢复合板腐蚀性能研究

本文对904L+14Cr1MoR(H)和904L+Q345R两种复合板675℃消应力退火热处理后进行了系统的腐蚀试验,结果表明:复层904L发生晶粒粗大化,晶间存在碳化物析出,抗腐蚀性能受热处理影响显著。ASTM G150法临界点蚀温度CPT≥40℃,一般不超过904L原始状态的CPT;ASTM 262B法腐蚀速率11 mm/a;GB/T4334E法腐蚀,试样弯曲外侧面无晶间裂纹出现。