On-Line Multi-Frequency Electrical Resistance Tomography (mfERT) Device for Crystalline Phase Imaging in High-Temperature Molten Oxide.

Kunihiko Nakashima,Miku Arisato,Koji Tanaka,Masahiro Takei,Yosephus Ardean Kurnianto Prayitno,Noritaka Saito,Panji Nursetia Darma,Prima Asmara Sejati

doi:10.3390/s22031025

Abstract

An on-line multi-frequency electrical resistance tomography (mfERT) device with a melt-resistive sensor and noise reduction hardware has been proposed for crystalline phase imaging in high-temperature molten oxide. The melt-resistive sensor consists of eight electrodes made of platinum-rhodium (Pt-20mass%Rh) alloy covered by non-conductive aluminum oxide (Al2O3) to prevent an electrical short. The noise reduction hardware has been designed by two approaches: (1) total harmonic distortion (THD) for the robust multiplexer, and (2) a current injection frequency pair: low and high , for thermal noise compensation. THD is determined by a percentage evaluation of k-th harmonic distortions of ZnO at .1~10,000 Hz. The and are determined by the thermal noise behavior estimation at different temperatures. At 00 Hz, the THD percentage is relatively high and fluctuates; otherwise, THD dramatically declines, nearly reaching zero. At the determined 10,000 Hz and 1,000,000 Hz, thermal noise is significantly compensated. The on-line mfERT was tested in the experiments of a non-conductive Al2O3 rod dipped into conductive molten zinc-borate (60ZnO-40B2O3) at 1000~1200 C. As a result, the on-line mfERT is able to reconstruct the Al2O3 rod inclusion images in the high-temperature fields with low error, = 5.99%, at 1000 C, and an average error = 9.2%.

Highlights

In steel industries, new functional steel materials are being developed for nextgeneration car and aerospace materials
In this paper, we propose a new concept of an on-line multi-frequency electrical resistance tomography device for the high-temperature spatio-temporal distribution of oxide crystal φ with two original aspects, which are: (1) the architecture of the melt-resistive sensor and (2) the design of noise reduction hardware, which consists of the specified total harmonic distortion (THD) for the robust multiplexer, and current injection frequency determination: low f L and high f H frequencies, for compensating the thermal noise
An on-line multi-frequency electrical resistance tomography device with a a melt-resistance sensor and noise reduction hardware has been proposed in a highmelt-resistance sensor and noise reduction hardware has been proposed in a high-temtemperature crucible for crystalline phase imaging

Summary

Introduction

New functional steel materials are being developed for nextgeneration car and aerospace materials. One of the critical points of developing new functional steel materials is the crystalline phase behaviors in high-temperature molten oxide, which influences steel material quality [1]. Several conventional off-line measurement methods were used to observe the crystalline behaviors, which are scanning electron microscopy (SEM) [2], X-ray diffraction (XRD) [3], differential scanning calorimetry (DSC), and differential thermal analysis (DTA) [4]. These measurement methods are able to observe the crystalline behaviors, but they are limited for observing its morphology and distribution. In order to enhance the measurement quality, thermogravimetric and differential thermal analysis (TG-DTA) was introduced for the recent steel industry application as a high-standard comprehensive measurement method

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