Transmission Electron Microscopy Characterization of High-Temperatur Oxidation of Fe-20Cr-5Al Alloy Prepared by Focused Ion Beam Technique

Abstract

The Focused Ion Beam (FIB) technique was applied for cross section preparation of the oxidized alloy for Transmission Electron Microscopy (TEM) study. Prior to preparation, the specimens of Fe-20Cr-5Al alloy sheet were oxidized in air at 1200 o C for 2 minutes, 10 minutes, 2 hours, and 100 hours. The microstructure and elemental composition of the samples were characterized using TEM equipped with an Energy Dispersive X-Ray Spectroscopy (EDX). The Electron Energy Loss Spectroscopy (EELS) was used to determine of the light elements. The TEM investigation reveals remarkable microstructure evolution of the specimens during oxidation which generally exhibit a typical multi-layer structure. The TEM images, however, can provide detailed description about the phases occur after oxidation such as the Tungsten (W) and the Gallium (Ga) layers on top of the samples obviously formed during FIB preparation, the formation of Al 2 O 3 and Cr 2 O 3 layer, MgAl 2 O 4 spinel, porosity, Zr/Hf/Mg phases or clusters inside the oxide scale. Hence, the FIB technique has been proven to be reliable preparation technique for microstructural and elemental studies of Fe-20Cr-5Al alloy using TEM. . Sebelum persiapan dilakukan, spesimen lembar aloi Fe-20Cr-5Al dioksidasi di udara pada suhu 1200 o C selama 2 menit, 10 menit, 2 jam, dan 100 jam. Struktur mikro dan komposisi elemen dari sampel tersebut dianalisis menggunakan TEM yang dilengkapi dengan Spektroskopi Sinar-X Energi Dispersif atau Energy Dispersive X-Ray Spectroscopy (EDX). Spektroskopi Kehilangan Energi Elektron atau Electron Energy Loss Spectroscopy (EELS) digunakan untuk menentukan elemen cahaya. Penggunaan TEM memperlihatkan evolusi struktur mikro yang luar biasa pada spesimen ketika oksidasi dilakukan, yang biasanya memperlihatkan struktur berlapis yang tipikal. Citra TEM memberikan deskripsi yang mendetail mengenai berbagai fase yang muncul setelah oksidasi, seperti lapisan Tungsten (W) dan Gallium (Ga) yang terbentuk di atas sampel selama masa persiapan FIB, pembentukan lapisan Al 2 O 3 dan Cr 2 O 3, spinel MgAl 2 O 4 , porositas, berbagai fase atau kelompok Zr/Hf/Mg di dalam skala oksida. Maka dari itu, teknik FIB telah terbukti sebagai teknik persiapan yang dapat diandalkan untuk meneliti struktur mikro dan elemen dari aloi Fe-20Cr-5Al dengan TEM. Abstrak

The Effect of Silica Concentration on The Absorption Properties of Silica-Based Ceramic Membrane

“…In the ceramic membrane before the sintering furnace, the presence of asymmetric O-H stretching vibrations from Si-OH which is O-H stretching at the absorption peak of 3391.9 cm-1 with a wide band was identified. This is to the FTIR analysis conducted by Rumiyanti et al, 2021 [6] which states that the presence of a wave peak of 3421.7 cm-1 will indicate the asymmetric O-H stretching vibration of Si-OH. Another absorption peak such as at 2885 cm-1 represents the C-H group, To Mansur et al, 2008 the wave band with the interval 2840 and 3000 cm-1 refers to C-H stretching.…”

“…TEM is one method that is widely agreed by scientists that ultrathin specimens of high quality are required for the investigation of almost all materials to the particle level [6]. Analysis using TEM has advantages such as being able to provide information about the composition of the sample with high resolution.…”