The Effect of Sample Preparation on the Microstructure of Austenitic-Ferritic Stainless Steel

2016 ◽  
Vol 879 ◽  
pp. 873-878 ◽  
Author(s):  
Timo Juuti ◽  
Sampo Uusikallio ◽  
Antti J. Kaijalainen ◽  
Esa Heinonen ◽  
Nyo Tun Tun ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Sample Preparation ◽  
Ferritic Stainless Steel ◽  
Laser Scanning ◽  
Focused Ion Beam ◽  
Electron Backscatter Diffraction ◽  
Ion Beam ◽  
Sample Surface ◽  
Laser Scanning Confocal Microscopy ◽  
Mechanical Polishing

Sample preparation of metastable austenitic-ferritic steels can have a significant effect on the apparent microstructure due to the transformation of austenite to martensite (γ - α'). As a result, these steels often have a complex microstructure with ferrite and martensite, which have relatively similar crystal structures, making it very difficult to analyse. However, the quantitative analysis of such microstructures and the effect of the sample preparation are very important for the further study of the steel. In this research, the effect of sample preparation in metastable austenitic-ferritic stainless steel was studied by using three different sample preparation methods. In addition to conventional mechanical etching with colloidical silica and electropolishing, focused ion beam (FIB) milling was used to create an optimal sample surface to be further analysed with electron backscatter diffraction (EBSD). Micrographs were obtained from each sample before and after sample preparation using field emission scanning electron microscopy (FESEM) and laser scanning confocal microscopy (LSCM), and the microstructure was analysed using EBSD. The surface flatness required for good EBSD analysis was significantly better using FIB milling than mechanical polishing, while electropolishing results in the greatest topography and an arched sample surface. The amount of martensite was found to be dependent on the sample preparation: least martensite was formed during electropolishing, while surprisingly mechanical polishing and FIB milling resulted in equal amounts of martensite.

Comparison of Precision XTEM Specimen Preparation Techniques for Semiconductor Failure Analysis

1997 ◽  
Vol 3 (S2) ◽  
pp. 357-358
Author(s):  
C. Amy Hunt
Keyword(s):  
Sample Preparation ◽  
Failure Analysis ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Mechanical Polishing ◽  
Specimen Preparation ◽  
Ion Milling ◽  
Tem Analysis ◽  
The Past ◽  
Preparation Techniques

The demand for TEM analysis in semiconductor failure analysis is rising sharply due to the shrinking size of devices. A well-prepared sample is a necessity for getting meaningful results. In the past decades, a significant amount of effort has been invested in improving sample preparation techniques for TEM specimens, especially precision cross-sectioning techniques. The most common methods of preparation are mechanical dimpling & ion milling, focused ion beam milling (FIBXTEM), and wedge mechanical polishing. Each precision XTEM technique has important advantages and limitations that must be considered for each sample.The concept for both dimpling & ion milling and wedge specimen preparation techniques is similar. Both techniques utilize mechanical polishing to remove the majority of the unwanted material, followed by ion milling to assist in final polishing or cleaning. Dimpling & ion milling produces the highest quality samples and is a relatively easy technique to master.

scholarly journals Mechanical Properties and Hydrogen Embrittlement of Laser-Surface Melted AISI 430 Ferritic Stainless Steel

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 140 ◽  
Author(s):  
W. K. Chan ◽  
C. T. Kwok ◽  
K. H. Lo
Keyword(s):  
Stainless Steel ◽  
Hydrogen Embrittlement ◽  
Strain Rate ◽  
Ferritic Stainless Steel ◽  
Laser Scanning ◽  
Electron Backscatter Diffraction ◽  
Microstructural Analysis ◽  
Scanning Speed ◽  
Laser Surface ◽  
Aisi 430

In the present study, the feasibility of laser surface melting (LSM) of AISI 430 ferritic stainless steel to minimize hydrogen embrittlement (HE) was investigated. LSM of AISI 430 steel was successfully achieved by a 2.3-kW high power diode laser (HPDL) with scanning speeds of 60 mm/s and 80 mm/s (the samples are designated as V60 and V80, respectively) at a power of 2 kW. To investigate the HE effect on the AISI 430 steel without and with LSM, hydrogen was introduced into specimens by cathodic charging in 0.1 M NaOH solution under galvanostatic conditions at a current density of 30 mA/cm2 and 25 °C. Detail microstructural analysis was performed and the correlation of microstructure with HE was evaluated. By electron backscatter diffraction (EBSD) analysis, the austenite contents for the laser-surface melted specimens V60 and V80 are found to be 0.6 and 1.9 wt%, respectively. The amount of retained austenite in LSM specimens was reduced with lower laser scanning speed. The surface microhardness of the laser-surface melted AISI 430 steel (~280 HV0.2) is found to be increased by 56% as compared with that of the substrate (~180 HV0.2) because of the presence of martensite. The degree of embrittlement caused by hydrogen for the charged and non-charged AISI 430 steel was obtained using slow-strain-rate tensile (SSRT) test in air at a strain rate of 3 × 10−5 s−1. After hydrogen pre-charging, the ductility of as-received AISI 430 steel was reduced from 0.44 to 0.25 while the laser-surface melted AISI 430 steel showed similar tensile properties as the as-received one. After LSM, the value of HE susceptibility Iδ decreases from 43.2% to 38.9% and 38.2% for V60 and V80, respectively, due to the presence of martensite.

scholarly journals Change in the Microstructure of Ferritic Stainless Steel with Surface Roughness and the Number of Thermal Cycles

2021 ◽  
Author(s):  
Myoung Youp SONG
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Oxide Layer ◽  
Ferritic Stainless Steel ◽  
Exposure Time ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Thermal Cycles ◽  
Total Oxygen ◽  
Oxygen Exposure

One of the candidates for metallic interconnects of solid oxide fuel cells is ferritic stainless steel, Crofer 22 APU. Ferritic stainless steel Crofer 22 APU specimens with different surface roughness were prepared by grinding with SiC powder papers of various grits and then thermally cycled in air. Variation in the microstructure of the samples having different roughness with thermal cycling was investigated. Polished Crofer 22 APU specimens after three and five thermal cycles had relatively flat oxide layers with thicknesses of about 13.8 and 17.9 μm, respectively. Micrographs of a trench made by milling with FIB (focused ion beam) for a Crofer 22 APU specimen ground with grit 80 SiC powder paper after 8 thermal cycles (total oxygen exposure time of 200 h at 1073 K), captured by ESB (energy selective back-scattering) and SE2 (type II secondary electrons), showed that the surface of the sample was very coarse and its oxide layer was undulated. In the oxide layer, the phase of the sublayer was Cr2O3, and that of the top layer was (Cr, Mn)3O4 spinel. The surface of the sample ground with grit 80 SiC powder paper was very rough after 60 thermal cycles (total oxygen exposure time of 1500 h at 1073 K). The polished Crofer 22 APU is a better applicant to an interconnect of SOFC than those with rougher surfaces.

Study on the Variation in Microstructure of a Ferritic Stainless Steel with Surface Roughness and Thermal Cycling in Air

2021 ◽  
Vol 21 (8) ◽  
pp. 4372-4382
Author(s):  
Myoung Youp Song ◽  
Daniel R. Mumm ◽  
Young Jun Kwak
Keyword(s):  
Stainless Steel ◽  
Oxide Layer ◽  
Ferritic Stainless Steel ◽  
Exposure Time ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Thermal Cycles ◽  
Total Oxygen ◽  
Oxygen Exposure ◽  
Better Than

A ferritic stainless steel, Crofer 22 APU, is one of candidates for metallic interconnects of solid oxide fuel cells. Ferritic stainless steel Crofer 22 APU specimens with different surface roughnesses were prepared by grinding with SiC powder papers of various grits and were then thermally cycled. Polished Crofer 22 APU specimens after one thermal cycle and five thermal cycles had relatively straight oxide layers with similar thicknesses of 30 μm, suggesting that after one cycle (total oxygen exposure time of 100 h at 1073 K), the oxidation does not progress. Micrographs of a trench made by milling with the FIB (focused ion beam) for a Crofer 22 APU specimen rubbed with grit 80 SiC powder paper after 8 thermal cycles (total oxygen exposure time of 200 h at 1073 K), captured by ESB, InLens, and SE2, showed that the surface of the sample was very coarse and its oxide layer was undulated. In the oxide layer, the phase of the sublayer was Cr2O3, and that of the top layer was (Cr, Mn)3O4 spinel. The sample ground with grit 80 SiC powder paper after 60 thermal cycles (total oxygen exposure time of 1500 h at 1073 K) was very coarse. Some ridges were quite straight and continuous. After 20 and 40 thermal cycles, ASR (area specific resistance) decreased as the number of grit of the SiC powder paper increased, suggesting that the polished Crofer 22 APU is better than those with rougher surfaces for application as an interconnect of SOFC.

Nanocomposite Polyurethane Foams Via POSS Blends

2002 ◽  
Vol 733 ◽  
Author(s):  
Brock McCabe ◽  
Steven Nutt ◽  
Brent Viers ◽  
Tim Haddad
Keyword(s):  
High Temperature ◽  
Sample Preparation ◽  
Room Temperature ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Polyurethane Foams ◽  
Development Projects ◽  
Polymer Systems ◽  
Polyurethane Resin ◽  
Military Development

AbstractPolyhedral Oligomeric Silsequioxane molecules have been incorporated into a commercial polyurethane formulation to produce nanocomposite polyurethane foam. This tiny POSS silica molecule has been used successfully to enhance the performance of polymer systems using co-polymerization and blend strategies. In our investigation, we chose a high-temperature MDI Polyurethane resin foam currently used in military development projects. For the nanofiller, or “blend”, Cp7T7(OH)3 POSS was chosen. Structural characterization was accomplished by TEM and SEM to determine POSS dispersion and cell morphology, respectively. Thermal behavior was investigated by TGA. Two methods of TEM sample preparation were employed, Focused Ion Beam and Ultramicrotomy (room temperature).

TEM Sample Preparation Tricks for Advanced DRAMs

2015 ◽  
Author(s):  
Ching Shan Sung ◽  
Hsiu Ting Lee ◽  
Jian Shing Luo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Integrated Circuit ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Characterization Of Materials

Abstract Transmission electron microscopy (TEM) plays an important role in the structural analysis and characterization of materials for process evaluation and failure analysis in the integrated circuit (IC) industry as device shrinkage continues. It is well known that a high quality TEM sample is one of the keys which enables to facilitate successful TEM analysis. This paper demonstrates a few examples to show the tricks on positioning, protection deposition, sample dicing, and focused ion beam milling of the TEM sample preparation for advanced DRAMs. The micro-structures of the devices and samples architectures were observed by using cross sectional transmission electron microscopy, scanning electron microscopy, and optical microscopy. Following these tricks can help readers to prepare TEM samples with higher quality and efficiency.

Analysis of Voltage Contrast in Secondary Electron Images Using a High-Energy Electron Spectrometer

2019 ◽  
Author(s):  
Natsuko Asano ◽  
Shunsuke Asahina ◽  
Natasha Erdman
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Sample Surface ◽  
High Energy ◽  
Secondary Electrons ◽  
Analysis Technique ◽  
Quantitative Understanding ◽  
Voltage Contrast ◽  
Acceleration Voltage ◽  
Failure Localization

Abstract Voltage contrast (VC) observation using a scanning electron microscope (SEM) or a focused ion beam (FIB) is a common failure analysis technique for semiconductor devices.[1] The VC information allows understanding of failure localization issues. In general, VC images are acquired using secondary electrons (SEs) from a sample surface at an acceleration voltage of 0.8–2.0 kV in SEM. In this study, we aimed to find an optimized electron energy range for VC acquisition using Auger electron spectroscopy (AES) for quantitative understanding.

To Eliminate Curtain Effect of FIB TEM Samples by a Combination of Sample Dicing and Backside Milling

2014 ◽  
Author(s):  
Jian-Shing Luo ◽  
Hsiu Ting Lee
Keyword(s):  
Sample Preparation ◽  
Focused Ion Beam ◽  
Preparation Method ◽  
Low Cost ◽  
Ion Beam ◽  
Sample Preparation Method ◽  
Site Specific ◽  
Dual Beam ◽  
Transmission Electron

Abstract Several methods are used to invert samples 180 deg in a dual beam focused ion beam (FIB) system for backside milling by a specific in-situ lift out system or stages. However, most of those methods occupied too much time on FIB systems or requires a specific in-situ lift out system. This paper provides a novel transmission electron microscopy (TEM) sample preparation method to eliminate the curtain effect completely by a combination of backside milling and sample dicing with low cost and less FIB time. The procedures of the TEM pre-thinned sample preparation method using a combination of sample dicing and backside milling are described step by step. From the analysis results, the method has applied successfully to eliminate the curtain effect of dual beam FIB TEM samples for both random and site specific addresses.

A Methodology to Reduce Ion Beam Induced Damage in TEM Specimens Prepared by FIB

2002 ◽  
Author(s):  
Chin Kai Liu ◽  
Chi Jen. Chen ◽  
Jeh Yan.Chiou ◽  
David Su
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Integrated Circuit ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Specimen Preparation ◽  
Tem Analysis ◽  
Sensitive Issue ◽  
Transmission Electron

Abstract Focused ion beam (FIB) has become a useful tool in the Integrated Circuit (IC) industry, It is playing an important role in Failure Analysis (FA), circuit repair and Transmission Electron Microscopy (TEM) specimen preparation. In particular, preparation of TEM samples using FIB has become popular within the last ten years [1]; the progress in this field is well documented. Given the usefulness of FIB, “Artifact” however is a very sensitive issue in TEM inspections. The ability to identify those artifacts in TEM analysis is an important as to understanding the significance of pictures In this paper, we will describe how to measure the damages introduced by FIB sample preparation and introduce a better way to prevent such kind of artifacts.

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