Interfacial Reactions and Thermal Stability of Ultrahigh Vacuum Deposited Multilayered Mo/Si Structures

1995 ◽  
Vol 382 ◽  
Author(s):  
J.M. Liang ◽  
L.J. Chen
Keyword(s):  
Thermal Stability ◽  
Function Analysis ◽  
Ultrahigh Vacuum ◽  
Interfacial Reactions ◽  
Silicide Phase ◽  
Transmission Electron ◽  
Bilayer Period ◽  
Auto Correlation Function ◽  
The Stability ◽  
Thermal Stability Of

ABSTRACTInterfacial reactions and thermal stability of ultrahigh vacuum deposited multilayered Mo/Si structures have been investigated by high resolution transmission electron microscopy in conjunction with fast Fourier transform and auto–correlation function analysis. For samples with nominal atomic ratios Mo:Si = 1:2 and 3:1, well defined multilayered Mo/Si structures were obtained after annealing at 250 °C for 30 min. On the other hand, distinct multilayered MoSi2/Si structure was formed only for Mo:Si = 1:2 samples after annealing at 650 °C for 1 h.Multiphases were observed to form simultaneously in samples annealed at 400–500 °C. After 650 °C annealing for 1 h, tetragonal MoSi2 was the only silicide phase observed for the Mo:Si = 1:2 samples, whereas both tetragonal and hexagonal MoSi2 were present in Mo:Si = 3:1 samples. The stability of the multilayered Mo/Si structures was found to depend critically on the atomic ratios of constituent elements, bilayer period and annealing conditions. The results are interpreted in terms of the delicate balance between intermixing of constituent atoms and silicide formation.

HRTEM Study of the Interfacial Reactions of High-Temperature Sputtered Ti Thin Films on Preamorphized (001)Si

1999 ◽  
Vol 564 ◽  
Author(s):  
S. M Chang ◽  
H. Y Yang ◽  
H. Y Huang ◽  
L. J. Chen
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Room Temperature ◽  
Function Analysis ◽  
Interfacial Reactions ◽  
Simultaneous Presence ◽  
Auto Correlation ◽  
Transmission Electron ◽  
Nucleation Sites ◽  
Auto Correlation Function

AbstractInterfacial reactions of high-temperature sputtered Ti thin films on preamorphized (001)Si have been investigated by high-resolution transmission electron microscopy in conjunction with auto-correlation function analysis. Simultaneous presence of multiphases was found to occur in the amorphous TiSix layer at the Ti/Si interface. The enhanced transformation of C54-TiSi2 in high-temperature deposited samples is attributed to the more extensive presence of silicide crystallites, which serve as nucleation sites, in the a-TiSix layer than that in samples deposited at room temperature.

Intrinsic Thermal Stability of Anisotropic Thin-Film Superconductors

1990 ◽  
Vol 112 (1) ◽  
pp. 10-15 ◽  
Author(s):  
M. I. Flik ◽  
C. L. Tien
Keyword(s):  
Thin Film ◽  
Thermal Stability ◽  
Stability Criterion ◽  
High Temperature Superconductors ◽  
Stability Criteria ◽  
Anisotropic Thermal Conductivity ◽  
Operating Current ◽  
Released Energy ◽  
The Stability ◽  
Thermal Stability Of

Intrinsic thermal stability denotes a situation where a superconductor can carry the operating current without resistance at all times after the occurrence of a localized release of thermal energy. This novel stability criterion is different from the cryogenic stability criteria for magnets and has particular relevance to thin-film superconductors. Crystals of ceramic high-temperature superconductors are likely to exhibit anisotropic thermal conductivity. The resultant anisotropy of highly oriented films of superconductors greatly influences their thermal stability. This work presents an analysis for the maximum operating current density that ensures intrinsic stability. The stability criterion depends on the amount of released energy, the Biot number, the aspect ratio, and the ratio of the thermal conductivities in the plane of the film and normal to it.

Simultaneous Occurrence of Multiphases in the Interfacial Reactions of Ultrahigh Vacuum Deposited Ti, Hf and Cr Thin Films on (111)Si

1993 ◽  
Vol 311 ◽  
Author(s):  
W.W. Hsieh ◽  
J.J. Lin ◽  
M.M. Wang ◽  
L.L. Chen
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Thin Films ◽  
Ultrahigh Vacuum ◽  
Interfacial Reactions ◽  
Simultaneous Occurrence ◽  
Image Simulation ◽  
Reaction Sequence ◽  
Transmission Electron ◽  
Amorphous Interlayer

ABSTRACTSimultaneous occurrence of multiphases was observed in the interfacial reactions of ultrahigh vacuum deposited Ti, Hf and Cr thin films on (111)Si by high resolution transmission electron microscopy in conjunction with fast Fourier transform diffraction analysis and image simulation. For the three systems, an amorphous interlayer as well as a number of crystalline phase were found to form simultaneously in the early stages of interfacial reactions. The formation of multiphases appeared to be quite general in the initial stages of interfacial reactions of UHV deposited refractory thin films. The results called for a reexamination of generally accepted “difference” in reaction sequence between bulk and thin film couples.

Formation and Thermal Stability of Nd0.32Y0.68Si1.7 Layers Formed by Channeled Ion Beam Synthesis

1998 ◽  
Vol 514 ◽  
Author(s):  
M. F. Wu ◽  
A. Vantomne ◽  
S. Hogg ◽  
H. Pattyn ◽  
G. Langouche ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Ion Beam ◽  
Hexagonal Structure ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Good Crystalline Quality ◽  
Ion Beam Synthesis ◽  
Thermal Stability Of

ABSTRACTThe Nd-disilicide, which exists only in a tetragonal or an orthorhombic structure, cannot be grown epitaxially on a Si(111) substrate. However, by adding Y and using channeled ion beam synthesis, hexagonal Nd0.32Y0.68Si1.7 epilayers with lattice constant of aepi = 0.3915 nm and cepi = 0.4152 nm and with good crystalline quality (χmin of Nd and Y is 3.5% and 4.3 % respectively) are formed in a Si(111) substrate. This shows that the addition of Y to the Nd-Si system forces the latter into a hexagonal structure. The epilayer is stable up to 950 °C; annealing at 1000 °C results in partial transformation into other phases. The formation, the structure and the thermal stability of this ternary silicide have been studied using Rutherford backscattering/channeling, x-ray diffraction and transmission electron microscopy.

scholarly journals Thermal Stability of Residual Stresses in Differently Deep Rolled Surface Layers of Steel SAE 1045

2021 ◽  
Author(s):  
Stephanie Saalfeld ◽  
Thomas Wegener ◽  
Berthold Scholtes ◽  
Thomas Niendorf
Keyword(s):  
Thermal Stability ◽  
Elevated Temperature ◽  
Residual Stresses ◽  
Elevated Temperatures ◽  
Fatigue Behavior ◽  
Decisive Role ◽  
Deep Rolling ◽  
Material Conditions ◽  
The Stability ◽  
Thermal Stability Of

AbstractThe stability of compressive residual stresses generated by deep rolling plays a decisive role on the fatigue behavior of specimens and components, respectively. In this regard, deep rolling at elevated temperature has proven to be very effective in stabilizing residual stresses when fatigue analysis is conducted at ambient temperature. However, since residual stresses can be affected not only by plastic deformation but also when thermal energy is provided, it is necessary to analyze the influence of temperature and time on the relaxation behavior of residual stresses at elevated temperature. To evaluate the effect of deep rolling at elevated temperatures on stability limits under thermal as well as combined thermo-mechanical loads, the present work introduces and discusses the results of investigations on the thermal stability of residual stresses in differently deep rolled material conditions of the steel SAE 1045.

scholarly journals Change in the stability of goat milk and cow milk due to pH and heat

2021 ◽  
Vol 233 ◽  
pp. 02046
Author(s):  
Xiaoxue Fan ◽  
Ming Cheng ◽  
Xiaoning Zhang ◽  
Cunfang Wang ◽  
Hua Jiang
Keyword(s):  
Thermal Stability ◽  
Milk Production ◽  
Ph Value ◽  
Goat Milk ◽  
Cow Milk ◽  
Type B ◽  
Fresh Milk ◽  
Ph Conditions ◽  
The Stability ◽  
Thermal Stability Of

This paper aimed to evaluate the changes in the thermal stability of goat milk, cow milk and homogenized milk under different pH conditions. The results showed that goat milk was of type B milk, and the thermal stability were positively correlated with the pH value. But cow milk was of type A milk, the most stable pH of fresh milk was 6.9, while it was 6.7 for homogenized cow milk. Compared with cow milk, the acidification of goat milk was stronger due to heat. Therefore, in the process of milk production, the germicidal heating conditions of two different milk sources should be determined according to their thermal stability.

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