Resonance Characteristic Study Of Magnetoelastic Material And Applications For Measurement Of Liquid Viscosity And Heavy Metal Ion

Due to high sensitivity, low cost, wireless measurement and passive nature, etc, magnetoelastic sensor has obtained lots of attention and developed quickly in the fields of non-destructive testing, biological detection, food safety and environmental monitoring. The paper mainly researched the resonance characteristic of magnetoelastic (ME) material, applied the ME sensor to measure liquid viscosity and heavy metal ion, developed a measurement system for resonant frequency of ME sensor. The main contents and conclusions of the paper are as follows:1) The measurement platform for resonant frequency of ME sensor was built. The resonance characteristic of three ME materials (METGLAS 2826MB^ 1K107 and 107K), resonance mode and some variable parameters (such as DC bias magnetic field, AC excited magnetic field, annealling treatment, material length and scan number, etc) which affect on the resonance characteristic were studied by the platform. It was found that there are five resonance peaks with great magnitude for METGLAS 2826MB material in the frequency range form 30kHz to 280kHz. The resonant frequencies and widths of at half maximum amplitudes of the peaks (n=1-4) are linear with the harmonic number, except the fifth peak. The DC field changes the resonance mode. Optmizing the AC field can improve the smoothness of resonance curve, which can help to determine the resonant frequency more accurately. Improving the unifomity of mass load can void the error response of ME sensor.2) The effect of liquid viscosity on the resonance characteristic were studied. The METGLAS 2826MB material was also used to measure the viscosity of human blood. It was found that resonance mode of high frequency makes the ME sensor have better sensitivity by comparing the reponses of METGLAS 2826MB material to viscosity in different resonance modes.3) A rapid detection method of heavy metal ion in liquid based on substitution reaction of Metglas 2826MB material was proposed. The low-cost ME material without any surface functionalization was used to contact with heavy metal ion solution. It was found that METGLAS 2826MB material can react with Pb(NO3)2 or Cu(SO3)2 solution. The content of iron on the surface of METGLAS 2826MB material decreases and the lead increases as time passes. The lead or copper which has been replaced locates evenly on the surface of ME material. The shift in resonant frequency of METGLAS 2826MB material increases with the solution concentration. The shift in resonant frequency of METGLAS 2826MB material with the dimension of 6mm×3mmx30μm is linear with the 5mg/ml-25mg/ml concentration of Pb(NO3)2 solution.4) The portable measurement device for resonant frequency of ME sensor were manufactured. By contrasts of experiment results, the feasibility of the device is verified.