Novel Crystallization Temperature Measurement Method for Combinatorial Evaluation using Infrared Thermography
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1159-G01-04
Novel crystallization temperature measurement method for combinatorial evaluation using infrared thermography Yuko Aono, Seiichi Hata, Junpei Sakurai and Akira Shimokohbe Precision and Intelligence Laboratory, Tokyo Institute of Technology, R2-40, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan ABSTRACT A novel measurement method of crystallization temperature (Tx) of thin film amorphous alloy is introduced. This proposed method is using thermography and detected Tx as change of thermal emissivity. Thin film metallic glass of Pd-Cu-Si was sputtered onto an alumina substrate and then heated at 20 K/min in vacuum, and the film apparent temperature monitored by thermography through BaF2 window on the vacuum chamber. The Tx measured by the method coincided with the Tx measured by conventional differential calorimeter within about 5 K. Using the method, Tx measurement on homogeneous composition thin film library was possible; Tx of all examined 128 thin film samples were measured at once and distributed within 10 K. INTRODUCTION Thin film amorphous alloys have attracted interest because of its homogeneity, high corrosion resistance and high mechanical strength so on. But amorphous alloy properties according to constitute elements or its composition, so for efficient searching or optimizing of new amorphous alloy, combinatorial method has been used in various alloy systems [1,2]. In this searching, how to evaluate each sample high through put is important. Especially, for amorphous alloy development, to evaluate the crystallization temperature, Tx, is important because it is a fundamental property and an indicator of amorphous thermal stability. Tx is conventionally measured using a differential scanning calorimeter (DSC). But this method is not suitable for combinatorial method. DSC requires sample amount at least about 10 mg and to place in the DSC measurement cell. In order to measure Tx of all samples on thin film library that is integrated samples by a combinatorial deposition method, the thin film library should be deposited enough thickness samples and divided into each samples. Then all these samples go through the time-consuming DSC measurement process. It includes inserting one sample into a DSC cell, setting the cell into the DSC chamber, measuring with heating, cooling, and finally taking out of the cell, and then moving on next sample. This measurement process spoils the efficiency of searching or optimizing of new amorphous alloy with combinatorial method [3]. A novel Tx measurement method has therefore been required for high-throughput evaluation of thin film library. In this research, novel Tx measurement method will be proposed. The method uses thermography, and Tx can be measured non-contact and in wide area with composition spread samples at once. This method can make high-throughput Tx evaluation possible with applying to the thin film library.
THEORY Thermography detects the infrared energy radiated from an object and displays its temperature distribution. The infrared radiation en
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