Chao-Nan Wei

Electrical and Physical Characteristics of WO3/Ag/WO3 Sandwich Structure Fabricated with Magnetic-Control Sputtering Metrology †

In this work, three layers of transparent conductive films of WO3/Ag/WO3 (WAW) were deposited on a glass substrate by radio frequency (RF) magnetron sputtering. The thicknesses of WO3 (around 50~60 nm) and Ag (10~20 nm) films were mainly the changeable factors to achieve the optimal transparent conductivity attempting to replace the indium tin oxide (ITO) in cost consideration. The prepared films were cardinally subjected to physical and electrical characteristic analyses by means of X-ray diffraction analysis (XRD), field-emission scanning electron microscope (FE-SEM), and Keithley 4200 semiconductor parameter analyzer. The experimental results show as the thickness of the Ag layer increases from 10 nm to 20 nm, the resistance becomes smaller. While the thickness of the WO3 layer increases from 50 nm to 60 nm, its electrical resistance becomes larger.

Heat Treatment Effects on the High Temperature Mechanical Behavior of Directionally Solidified Mar‐M247 Superalloy

In this study, two heat treatment schemes were proposed to study the high temperature mechanical behavior of directionally solidified MAR-M247 superalloy with withdraw rate of 180 mm/h. Standard heat treatment (HT1) procedures are solution treatment at 1230°C for 2 h/GFQ, then first aging at 980°C for 5 h/AC and followed by second aging at 870°C for 20 h/AC. Modified heat treatment (HT2) is solution treatment at 1260°C for 3 h/GFQ and first aging at 980°C for 6 h/AC, then the same second aging procedure. Uneven size and shape of gamma prime precipitates are observed after full HT1 scheme, whereas even size but fusion-alike gamma prime precipitates are observed in HT2 specimen. Creep tests at high temperature/low stress (982°C/200MPa) conditions show similar creep rupture life but low extension rate of HT1 specimen. Uneven size and shape of gamma prime precipitates of HT1 specimen effectively prevent dislocation motion. However, the yield strength, tensile strength and elongation to failure of HT2 specimens at 982°C are higher than these of HT1 specimens.