Preparation And Characterization Of Assre By EB-PVD Used In Corrosion Monitoring Of Rc Structures

Corrosion of reinforcing steel is one of the main factors, which cause the durability degeneration of reinforced concrete structures and bring huge economic losses. Corrosion monitoring of reinforcing steel provides the scientific basis for corrosion protection, security assessment and the whole life design of reinforced concrete structures. Corrosion monitoring sensors are the carrier and platform for the realization of steel corrosion monitoring. The reference electrode is the core component of electrochemical corrosion monitoring sensors. The development of all solid-state reference electrode (ASSRE) with excellent service performance is a key scientific issue for implementing the corrosion monitoring sensor system of reinforced concrete structures. In this paper, binary alloy functional cores with excellent service performance are developed by using the advanced membrane technology-electron beam physical vapor deposition (EB-PVD). The alloy films of the functional cores are systematically microcosmically characterized and analyzed. The response of the ASSRE integrated with the developed alloy thin films is tested in typical service environment. Finally, the ASSRE is integrated into a series of corrosion sensors to monitor the corrosion of reinforced concrete slabs. This paper aims to provide core components for the corrosion sensors used in structural health monitoring and lay the foundation for the large-scale and integrated production of corrosion sensors. Main contents of this paper are as follows:(1) Combined with the specific requirements on functional cores of ASSRE, the specific preparation process of the binary alloy thin films by using EB-PVD technology is determined. The preparation process of the conductive layer and the process conditions of the heat treatment and postoxidation of the prepared alloy films are definitized. A micro-analysis method for the binary alloy film and a performance testing method for the ASSRE are proposed, respectively.(2) The prepared, heat treated and oxidized binary alloy films are micro-analyzed by using various material analysis methods such as SEM, XRD and pole figure. The specific process of the heat treatment and postoxidation is determined from the micro-analysis of the films in different states.(3) ASSRE is assembled and its electrochemical performance is tested. The test results show that the developed ASSRE has good long-term potential stability, excellent anti-interference performance to external ions, and favorite anti-polarization property. The temperature response coefficient of the ASSRE is in the range from 0.40 to 0.49 mV/℃. (4) The five-electrode corrosion sensors and wireless corrosion sensor networks for corrosion monitoring of reinforced concrete structures are integrated with the developed ASSRE. The corrosion monitoring of reinforced concrete slabs with accelerated corrosion is performed by using constant potential step sub-analysis and electrochemical noise wavelet power spectrum method. The reliability of the ASSRE and the integrated corrosion monitoring system is verified.