scholarly journals Effect of SiO2–Al2O3 Glass Composite Coating on the Oxidation Behavior of Ti60 Alloy

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5085
Author(s):  
Wenbo Li ◽  
Ken Chen ◽  
Lanlan Liu ◽  
Yingfei Yang ◽  
Shenglong Zhu
Keyword(s):  
Composite Coating ◽  
Oxygen Diffusion ◽  
Electron Probe ◽  
Mass Gain ◽  
Glass Composite ◽  
Temperature Oxidation ◽  
Electron Probe Microanalyzer ◽  
Catastrophic Oxidation ◽  
Baking Process ◽  
Oxidation Performance

A SiO2–Al2O3 glass composite coating was prepared on Ti60 alloy via air spraying slurry and then a suitable baking process. It was composed of potassium silicate glass, alumina and quartz powders. The high temperature oxidation performance of the alloy with and without coating was evaluated in static air at both 800 °C and 900 °C. The results show that catastrophic oxidation occurs for Ti60 bare alloy. It had a mass gain of about 2 mg/cm2 after oxidation at 800 °C and 17 mg/cm2 at 900 °C for 100 h. On the contrary, the oxidation resistance of alloy coated with composite coating was much improved with the mass gain about 0.36 mg/cm2 and 0.95 mg/cm2 at 800 °C and at 900 °C, respectively. The microstructure evolution of the composite coating and the alloy was analyzed by scanning electron microscope and electron probe microanalyzer. The effect of the composite coating on the oxidation performance of the alloy is discussed especially in terms of oxygen diffusion and interfacial reaction.

scholarly journals Isothermal Oxidation Performance of Laser Cladding Assisted with Preheat (LCAP) Tribaloy T-800 Composite Coatings Deposited on EN8

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 843
Author(s):  
Sipiwe Trinity Nyadongo ◽  
Sisa Lesley Pityana ◽  
Eyitayo Olatunde Olakanmi
Keyword(s):  
Iron Oxide ◽  
Composite Coating ◽  
Laser Cladding ◽  
Composite Coatings ◽  
Parabolic Rate Constant ◽  
Mass Gain ◽  
Isothermal Oxidation ◽  
Operational Parameters ◽  
Temperature Oxidation ◽  
Service Environments

It is anticipated that laser cladding assisted with preheat (LCAP)-deposited Tribaloy (T-800) composite coatings enhances resistance to structural degradation upon exposure to elevated-temperature oxidation service environments. The oxidation kinetics of LCAP T-800 composite coatings deposited on EN8 substrate and its mechanisms have not been explored in severe conditions that are similar to operational parameters. The isothermal oxidation behaviour of the T-800 composite coating deposited on EN8 via LCAP was studied at 800 °C in air for up to 120 h (5 × 24 h cycles) and contrasted to that of uncoated samples. The mass gain per unit area of the coating was eight times less than that of the uncoated EN8 substrate. The parabolic rate constant (Kp) for EN8 was 6.72 × 10−12 g2·cm−4·s−1, whilst that for the T-800 composite coating was 8.1 × 10−13 g2·cm−4·s−1. This was attributed to a stable chromium oxide (Cr2O3) layer that formed on the coating surface, thereby preventing further oxidation, whilst the iron oxide film that formed on the EN8 substrate allowed the permeation of the oxygen ions into the oxide. The iron oxide (Fe2O3) film that developed on EN8 spalled, as evidenced by the cracking of oxide when the oxidation time was greater than 72 h, whilst the Cr2O3 film maintained its integrity up to 120 h. A parabolic law was observed by the T-800 composite coating, whilst a paralinear law was reported for EN8 at 800 °C up to 120 h. This coating can be used in turbine parts where temperatures are <800 °C.

Quantitative EPMA of nitrogen : A tricky element in the electron-probe microanalyzer

1992 ◽  
Vol 50 (2) ◽  
pp. 1622-1623
Author(s):  
G.F. Bastin ◽  
H.J.M. Heijligers
Keyword(s):  
Background Subtraction ◽  
Electron Probe ◽  
Detection System ◽  
Higher Order ◽  
Light Elements ◽  
Strong Suppression ◽  
Electron Probe Microanalyzer ◽  
Quantitative Epma ◽  
Peak Count ◽  
Lead Stearate

Among the ultra-light elements B, C, N, and O nitrogen is the most difficult element to deal with in the electron probe microanalyzer. This is mainly caused by the severe absorption that N-Kα radiation suffers in carbon which is abundantly present in the detection system (lead-stearate crystal, carbonaceous counter window). As a result the peak-to-background ratios for N-Kα measured with a conventional lead-stearate crystal can attain values well below unity in many binary nitrides . An additional complication can be caused by the presence of interfering higher-order reflections from the metal partner in the nitride specimen; notorious examples are elements such as Zr and Nb. In nitrides containing these elements is is virtually impossible to carry out an accurate background subtraction which becomes increasingly important with lower and lower peak-to-background ratios. The use of a synthetic multilayer crystal such as W/Si (2d-spacing 59.8 Å) can bring significant improvements in terms of both higher peak count rates as well as a strong suppression of higher-order reflections.

Measurement And Simulation Of X-Ray Emission From Multilayered Structures In Electron Probe Microanalysis.

1999 ◽  
Vol 5 (S2) ◽  
pp. 78-79
Author(s):  
C. Merlet ◽  
X. Llovet ◽  
F. Salvat
Keyword(s):  
Electron Probe ◽  
Numerical Models ◽  
Carbon Layer ◽  
Single Element ◽  
Surface Ionization ◽  
Copper Films ◽  
Multilayered Structures ◽  
X Ray ◽  
Electron Probe Microanalyzer ◽  
Quantitative Epma

Studies of x-ray emission from thin films on substrates using an electron probe microanalyzer (EPMA) provide useful information on the characteristics of x-ray generation by electron beams. In this study, EPMA measurements of multilayered samples were performed in order to test and improve analytical and numerical models used for quantitative EPMA. These models provide relatively accurate results for samples consisting of layers with similar average atomic numbers, because of their similar properties regarding electron transport and x-ray generation. On the contrary, these models find difficulties to describe the process when the various layers have very different atomic numbers. In a previous work, we studied the surface ionization of thin copper films of various thicknesses deposited on substrates with very different atomic numbers. In the present communication, the study is extended to the case of multilayered specimens.The studied specimens consisted of thin copper films deposited on a carbon layer which, in turn, was placed on a variety of single-element substrates, ranging from Be to Bi.

scholarly journals The Effect of Al on the Formation of a CrTaO4 Layer in Refractory High Entropy Alloys Ta-Mo-Cr-Ti-xAl

2021 ◽  
Author(s):  
S. Schellert ◽  
B. Gorr ◽  
H.- J. Christ ◽  
C. Pritzel ◽  
S. Laube ◽  
...  
Keyword(s):  
Mass Gain ◽  
Positive Influence ◽  
High Entropy Alloys ◽  
Oxide Scales ◽  
Temperature Oxidation ◽  
Internal Corrosion ◽  
High Entropy ◽  
Continuous Mass ◽  
Oxide Substrate ◽  
Kinetics Of

AbstractIn this study, the effect of Al on the high temperature oxidation of Al-containing refractory high entropy alloys (RHEAs) Ta-Mo-Cr-Ti-xAl (x = 5; 10; 15; 20 at%) was examined. Oxidation experiments were performed in air for 24 h at 1200 °C. The oxidation kinetics of the alloy with 5 at% Al is notably affected by the formation of gaseous MoO3 and CrO3, while continuous mass gain was detected for alloys with the higher Al concentrations. The alloys with 15 and 20 at% Al form relatively thin oxide scales and a zone of internal corrosion due to the formation of dense CrTaO4 scales at the interface oxide/substrate. The alloys with 5 and 10 at% Al exhibit, on the contrary, thick and porous oxide scales because of fast growing Ta2O5. The positive influence of Al on the formation of Cr2O3 followed by the growth of CrTaO4 to yield a compact scale is explained by getter and nucleation effects.

Formation mechanism of Sn-patch between SnAgCu solder and Ti/Ni(V)/Cu under bump metallization

2009 ◽  
Vol 24 (8) ◽  
pp. 2638-2643 ◽  
Author(s):  
Kai-Jheng Wang ◽  
Yan-Zuo Tsai ◽  
Jenq-Gong Duh ◽  
Toung-Yi Shih
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Formation Mechanism ◽  
Transmission Electron Microscope ◽  
Electron Probe ◽  
Under Bump Metallization ◽  
Rich Phase ◽  
Snagcu Solder ◽  
Electron Probe Microanalyzer ◽  
Transmission Electron

An Sn-patch formed in Ni(V)-based under bump metallization during reflow and aging. To elucidate the evolution of the Sn-patch, the detailed compositions and microstructure in Sn–Ag–Cu and Ti/Ni(V)/Cu joints were analyzed by a field emission electron probe microanalyzer (EPMA) and transmission electron microscope (TEM), respectively. There existed a concentration redistribution in the Sn-patch, and its microstructure also varied with aging. The Sn-patch consisted of crystalline Ni and an amorphous Sn-rich phase after reflow, whereas V2Sn3 formed with amorphous an Sn-rich phase during aging. A possible formation mechanism of the Sn-patch was proposed.

Oxidation Behavior of TiAl Based Alloys Prepared by Spark Plasma Sintering

2010 ◽  
Vol 152-153 ◽  
pp. 940-944
Author(s):  
Hua Chen ◽  
Jing Chao Zhang ◽  
X.Y Lu
Keyword(s):  
Mechanical Alloying ◽  
Spark Plasma Sintering ◽  
Oxidation Behavior ◽  
Mass Gain ◽  
Vacuum Sintering ◽  
Temperature Oxidation ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
High Temperature Oxidation Behavior ◽  
Fully Lamellar

The spark plasma sintering (SPS) microstructure and high temperature oxidation behavior of TiH2-45Al-0.2Si-5Nb(at.%) alloy were investigated.Emphasis was placed on the effect of SPS microstructures, obtained by blend powder and mechanical alloying powder. The mass gain due to oxidation was measured using an electro balance. The oxide layers as well as its micro-structure were examined by SEM and EDS, and XRD. The results show that sintered microstructure of blend powder is composed of fully lamellar TiAl/ Ti3Al phase, and that of the mechanical alloying powder is composed of finer granular TiAl/Ti3Al phase. The latter oxidation rate is lower, and forms continuous mixed oxide layer of Al2O3 and TiO2. Both SPS microstructure of blend powder and mechanical alloying powder are superior in oxidation behavior to ordinary vacuum sintering.

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