scholarly journals Chemically graded Fe–Al/steel samples fabricated by laser metal deposition

MRS Advances ◽  
2017 ◽  
Vol 2 (26) ◽  
pp. 1393-1398 ◽  
Author(s):  
Saeid Lotfian ◽  
Gesa Rolink ◽  
Andreas Weisheit ◽  
Martin Palm
Keyword(s):  
Metal Deposition ◽  
Concentration Profiles ◽  
Laser Metal Deposition ◽  
Concentration Gradients ◽  
Long Term Stability ◽  
Wavelength Dispersive Spectrometry ◽  
Heat Treated ◽  
Composition Gradients ◽  
Scanning Electron

ABSTRACTBy laser metal deposition (LMD) samples from Fe–28Al (at.%) have been built on iron and various steels. Chemically graded iron aluminium and Fe–28Al/steel samples were fabricated with intended concentration gradients by controlling the feed rates of the powders. All samples were subsequently heat treated at 700 °C for 1000 h to study possible reactions between Fe–28Al and the steels and the long-term stability of the composition gradients. Microstructures were characterized by scanning electron microscopy (SEM) and concentration profiles along the building direction were analysed by energy- and wavelength-dispersive spectrometry (EDS, WDS).

Effect of Double-Step Solution Treatment on Rejuvenation Heat Treated Microstructure of IN-738 Superalloy

2020 ◽  
Vol 856 ◽  
pp. 36-42
Author(s):  
Chuleeporn Paa-Rai
Keyword(s):  
Heat Treatment ◽  
Image Analysis ◽  
Electron Microscope ◽  
Solution Treatment ◽  
Single Step ◽  
Double Step ◽  
Heat Treated ◽  
Cast Superalloy ◽  
Scanning Electron

This work investigates the effect of rejuvenation heat treatment, with double-step solution treatment at the temperature from 1150 °C to 1200 °C, on the recovered microstructure of IN-738 cast superalloy. The superalloy has been long-term exposed as a turbine blade in a gas turbine prior to this study. After double solution treatment and aging at 845 °C for 12 h and 24 h, the recovered microstructures were examined by using a scanning electron microscope. Coarse γ΄ particles, that have presented in damaged microstructures, could not be observed in the samples after the rejuvenation heat treatment. In addition, the image analysis illustrates that the reprecipitated γ΄ particles in the samples with double-step solution treatments increase significantly in sizes during aging than that in the samples with the single-step solution treatment. Furthermore, the measurement of the samples hardness presents that the as-receive sample hardness is improved after rejuvenation heat treatment studied in this work.

Long-term stability of hydrogen and organic acids production in an anaerobic fluidized-bed reactor using heat treated anaerobic sludge inoculum

2009 ◽  
Vol 34 (9) ◽  
pp. 3679-3688 ◽  
Author(s):  
Gessia Momoe Shida ◽  
Aruana Rocha Barros ◽  
Cristiane Marques dos Reis ◽  
Eduardo Lucena Cavalcante de Amorim ◽  
Márcia Helena Rissato Zamariolli Damianovic ◽  
...  
Keyword(s):  
Organic Acids ◽  
Fluidized Bed ◽  
Fluidized Bed Reactor ◽  
Anaerobic Sludge ◽  
Term Stability ◽  
Long Term Stability ◽  
Heat Treated ◽  
Anaerobic Fluidized Bed Reactor

Test Specimens For High Resolution Scanning Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 238-239
Author(s):  
Raymond T. Greer
Keyword(s):  
Electron Microscopy ◽  
Test Specimen ◽  
Low Cost ◽  
Silica Spheres ◽  
High Quality ◽  
Low Contrast ◽  
Long Term Stability ◽  
Closest Packing ◽  
Scanning Electron

A useful resolution specimen for day-to-day SEM instrument standardization should exhibit uniform, periodic microstructure of hundreds to thousands of angstroms, show low contrast, have low cost, be easily prepared, and demonstrate long term stability.Opal (Figure 1) is particularly useful as a resolution specimen; however, several aspects of sample preparation should be emphasized. A high quality gem opal chip a few millimeters in diameter is sufficient for carefully controlled etching in, for example, 10% HF for 30 seconds. The choice of test specimen microstructure size is established by the maximum wavelength of color observed under white light. The iridescence effect is dictated by the microstructure of uniform silica spheres arranged in a cubic closest packing array.

Investigation of long term stability of arc-induced gratings heat treated at high temperatures

2010 ◽  
Author(s):  
Gaspar Rego ◽  
Paulo Caldas ◽  
Oleg Ivanov ◽  
José Luís Santos
Keyword(s):  
High Temperatures ◽  
Term Stability ◽  
Long Term Stability ◽  
Heat Treated

scholarly journals In Vitro Comparison of the Efficacy of Peri-Implantitis Treatments on the Removal and Recolonization of Streptococcus gordonii Biofilm on Titanium Disks

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2484 ◽  
Author(s):  
Selena Toma ◽  
Catherine Behets ◽  
Michel C. Brecx ◽  
Jerome F. Lasserre
Keyword(s):  
Electron Microscopy ◽  
Control Group ◽  
Streptococcus Gordonii ◽  
Long Term Stability ◽  
Dental Biofilm ◽  
Clinical Procedures ◽  
Scanning Electron ◽  
In Vitro Comparison

Objective: To compare the efficacy of four commonly used clinical procedures in removing Streptococcus gordonii biofilms from titanium disks, and the recolonization of the treated surfaces. Background: Successful peri-implantitis treatment depends on the removal of the dental biofilm. Biofilm that forms after implant debridement may threaten the success of the treatment and the long-term stability of the implants. Methods: S. gordonii biofilms were grown on titanium disks for 48 h and removed using a plastic curette, air-abrasive device (Perio-Flow®), titanium brush (TiBrush®), or implantoplasty. The remaining biofilm and the recolonization of the treated disks were observed using scanning electron microscopy and quantified after staining with crystal violet. Surface roughness (Ra and Rz) was measured using a profilometer. Results: S. gordonii biofilm biomass was reduced after treatment with Perio-Flow®, TiBrush®, and implantoplasty (all p < 0.05), but not plastic curette (p > 0.05), compared to the control group. Recolonization of S. gordonii after treatment was lowest after Perio-Flow®, TiBrush®, and implantoplasty (all p < 0.05 vs. control), but there was no difference between the plastic curette and the control group (p > 0.05). Ra and Rz values ranged from 1–6 µm to 1–2 µm and did not differ statistically between the control, plastic curette, Perio-Flow, and TiBrush groups. However, the implantoplasty group showed a Ra value below 1 µm (p < 0.01, ANOVA, Tukey). Conclusions: Perio-Flow®, TiBrush®, and implantoplasty were more effective than the plastic curette at removing the S. gordonii biofilm and preventing recolonization. These results should influence the surgical management of peri-implantitis.

Fluxless Microjoining by Au-In-Ni Isothermal Solidification

1999 ◽  
Vol 605 ◽  
Author(s):  
M. Waelti ◽  
N. Schneeberger ◽  
O. Brand ◽  
H. Baltes
Keyword(s):  
Electron Microscopy ◽  
Bonding Temperature ◽  
Optical Filter ◽  
High Strength ◽  
Isothermal Solidification ◽  
High Thermal Stability ◽  
Reflow Soldering ◽  
Long Term Stability ◽  
Scanning Electron

AbstractA reliable, fluxless microjoining technique based on isothermal solidification is reported. The Au-In-Ni system has been chosen for bonding, because gold is often applied for wafer bumping, and Ni is commonly used for substrate plating. To demonstrate the potential of this microjoining scheme, optical filter have been directly attached to a smart CMOS thermoelectric IR system. Since further packaging of the microsystem includes SMT assembly, the bond has to withstand subsequent SnPb reflow-soldering.The influence of bonding time and temperature on the bond was investigated. Phase formation and transformation were analyzed by light and scanning electron microscopy (SEM). Bonding performed at temperatures below 200°C remained stable even after multiple soldering cycles with peak temperatures of 235°C. The shear strength of the bonds was found to be more than 70 MPa. Long term stability was confirmed by extended anneal at 160°C. The method is generally well suited for processes involving sequences of joining steps, and for bonds demanding high strength and high thermal stability at low bonding temperature.

Investigation of the long-term stability of arc-induced gratings heat treated at high temperatures

2011 ◽  
Vol 284 (1) ◽  
pp. 169-171 ◽  
Author(s):  
Gaspar Rego ◽  
Paulo Caldas ◽  
Oleg Ivanov ◽  
José Luís Santos
Keyword(s):  
High Temperatures ◽  
Term Stability ◽  
Long Term Stability ◽  
Heat Treated

Stability and Change in Emotional Intelligence: Exploring the Transition to Young Adulthood

2005 ◽  
Vol 26 (2) ◽  
pp. 100-106 ◽  
Author(s):  
James D.A. Parker ◽  
Donald H. Saklofske ◽  
Laura M. Wood ◽  
Jennifer M. Eastabrook ◽  
Robyn N. Taylor
Keyword(s):  
High School ◽  
Emotional Intelligence ◽  
Postsecondary Education ◽  
Life Transition ◽  
Full Time ◽  
Major Life ◽  
Long Term Stability ◽  
Time Period ◽  
Transition From High School

Abstract. The concept of emotional intelligence (EI) has attracted growing interest from researchers working in various fields. The present study examined the long-term stability (32 months) of EI-related abilities over the course of a major life transition (the transition from high school to university). During the first week of full-time study, a large group of undergraduates completed the EQ-i:Short; 32 months later a random subset of these students (N = 238), who had started their postsecondary education within 24 months of graduating from high school, completed the measures for a second time. The study found EI scores to be relatively stable over the 32-month time period. EI scores were also found to be significantly higher at Time 2; the overall pattern of change in EI-levels was more than can be attributed to the increased age of the participants.

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