Advanced technology for in-line continuous heat soak test of tempered sheet glass to guarantee high reliability

2020 ◽  
Vol 61 (1) ◽  
pp. 16-24
Author(s):  
Chihiro Sakai
Keyword(s):  
High Temperature ◽  
Sheet Glass ◽  
High Reliability ◽  
Advanced Technology ◽  
Experimental Investigations ◽  
Nickel Sulphide ◽  
Raman Spectrometry ◽  
Β Phase ◽  
Safety And Reliability ◽  
Heat Soak Test

Advanced heat soak test (HST) technology, the ‘in-line continuous HST’ has been reported on the basis of experimental investigations and the T-T-T (time–temperature–transformation) relationship. The new HST technology is continuously carried out just after tempering (and heat strengthening) process. It was registered in ISO-20657 (2017). High temperature microscopy observations, high temperature x-ray diffractometry, differential thermal analysis, and micro-Raman spectrometry have been carried out in order to elucidate the α–β phase transformation of nickel sulphide in detail. The breakage ratio of in-line continuous HST is the same as that of conventional off-line HST or excellent. The ‘in-line continuous HST’ is already operating in a Japanese glass plant in order to produce tempered (and heat strengthened) sheet glass with high safety and reliability. The in-line continuous HST technology has the following benefits: (a) improvements of both productivity and reliability, (b) automatic inspection just after the tempering–quenching process, and (c) improvements to productive performance (many kinds products, heteromorphic products, and mass production). In this technical report, the advanced ‘in-line continuous HST’ technology which was standardised by several experimental investigations and analytical results will be shown in detail. The effective and efficient manufacturing technology of the tempered (and heat strengthened) sheet glass will be introduced.

Low-Temperature Post-Oxidation Annealing Using Atomic Hydrogen Radicals Generated by High-Temperature Catalyzer for Improvement in Reliability of Thermal Oxides on 4H-SiC

2006 ◽  
Vol 527-529 ◽  
pp. 999-1002
Author(s):  
Junji Senzaki ◽  
Atsushi Shimozato ◽  
Kenji Fukuda
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Atomic Hydrogen ◽  
High Reliability ◽  
Hydrogen Atmosphere ◽  
Exposed Sample ◽  
New Apparatus ◽  
Hydrogen Radical ◽  
Hydrogen Radicals ◽  
Sic Wafer

Low-temperature post-oxidation annealing (POA) process of high-reliability thermal oxides grown on 4H-SiC using new apparatus that generates atomic hydrogen radicals by high-temperature catalyzer has been investigated. Atomic hydrogen radicals were generated by thermal decomposition of H2 gas at the catalyzer surface heated at high temperature of 1800°C, and then exposed to the sample at 500°C in reactor pressure of 20 Pa. The mode and maximum values of field-to-breakdown are 11.0 and 11.2 MV/cm, respectively, for the atomic hydrogen radical exposed sample. In addition, the charge-to-breakdown at 63% cumulative failure of the thermal oxides for atomic hydrogen radical exposed sample was 0.51 C/cm2, which was higher than that annealed at 800°C in hydrogen atmosphere (0.39 C/cm2). Consequently, the atomic hydrogen radical exposure at 500°C has remarkably improved the reliability of thermal oxides on 4H-SiC wafer, and is the same effect with high-temperature hydrogen POA at 800°C.

Mechanical Alloying Behavior in the Nb-Si, Ta-Si, and Nb-Ta-Si Systems

1988 ◽  
Vol 133 ◽  
Author(s):  
K. S. Kumar ◽  
S. K. Mannan
Keyword(s):  
High Temperature ◽  
Mechanical Alloying ◽  
Mechanical Milling ◽  
Room Temperature ◽  
Crystalline Compound ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Α Phase

ABSTRACTThe mechanical alloying behavior of elemental powders in the Nb-Si, Ta-Si, and Nb-Ta-Si systems was examined via X-ray diffraction. The line compounds NbSi2 and TaSi2 form as crystalline compounds rather than amorphous products, but Nb5Si3 and Ta5Si3, although chemically analogous, respond very differently to mechanical milling. The Ta5Si3 composition goes directly from elemental powders to an amorphous product, whereas Nb5Si3 forms as a crystalline compound. The Nb5Si3 compound consists of both the tetragonal room-temperature α phase (c/a = 1.8) and the tetragonal high-temperature β phase (c/a = 0.5). Substituting increasing amounts of Ta for Nb in Nb5Si3 initially stabilizes the α-Nb5Si3 structure preferentially, and subsequently inhibits the formation of a crystalline compound.

scholarly journals Room-temperature oxygen vacancy migration induced reversible phase transformation during the anelastic deformation in CuO

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lei Li ◽  
Guoxujia Chen ◽  
He Zheng ◽  
Weiwei Meng ◽  
Shuangfeng Jia ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxygen Vacancy ◽  
Room Temperature ◽  
High Temperature Superconductivity ◽  
Experimental Investigations ◽  
Solid State Chemistry ◽  
Vacancy Migration ◽  
Scientific Disciplines ◽  
Anelastic Deformation ◽  
Reversible Phase

AbstractFrom the mechanical perspectives, the influence of point defects is generally considered at high temperature, especially when the creep deformation dominates. Here, we show the stress-induced reversible oxygen vacancy migration in CuO nanowires at room temperature, causing the unanticipated anelastic deformation. The anelastic strain is associated with the nucleation of oxygen-deficient CuOx phase, which gradually transforms back to CuO after stress releasing, leading to the gradual recovery of the nanowire shape. Detailed analysis reveals an oxygen deficient metastable CuOx phase that has been overlooked in the literatures. Both theoretical and experimental investigations faithfully predict the oxygen vacancy diffusion pathways in CuO. Our finding facilitates a better understanding of the complicated mechanical behaviors in materials, which could also be relevant across multiple scientific disciplines, such as high-temperature superconductivity and solid-state chemistry in Cu-O compounds, etc.

Controlling the Reactivity of C60: A Theoretical Analysis of the Electronic States Modulated by Substitutional Chemistry

1994 ◽  
Vol 359 ◽  
Author(s):  
S.-H. Wang ◽  
M. Kashani ◽  
S. Jansen
Keyword(s):  
High Temperature ◽  
Theoretical Analysis ◽  
High Temperature Superconductivity ◽  
Electronic States ◽  
Experimental Investigations ◽  
Cluster Stability ◽  
Simple Substitution ◽  
Doped Materials ◽  
Multiple Species

ABSTRACTThe availability of large amounts of Buckminsterfullerene has allowed a plethora of experimental investigations on fullerenes. The chemical and physical studies have focussed on synthesis, isomerism, magnetism, spectroscopy and high temperature superconductivity in doped materials. The chemical reactivities of fullerenes have been defined and most of the studies are dominated by C60 isomers. Some of the observed activities of fullerenes parlled those of alkeies. In our previous studies, the reactivity of the 6-6' bond with respect to eco- addition was described. Current studies have exploited the olefinic nature of the 6-6' bond and analyzed the effect of the addition on cluster stability and frontier character. In this work, we describe the mechanisms of simple substitution and analyze stability and orbital effects for the addition chemistry of C60 with multiple species. Evolving changes in orbital frontier character are analyzed with respect to site directed chemistry exhibited by C60.

scholarly journals Tailoring Microstructure and Mechanical Properties of Additively-Manufactured Ti6Al4V Using Post Processing

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 658
Author(s):  
Yaron Itay Ganor ◽  
Eitan Tiferet ◽  
Sven C. Vogel ◽  
Donald W. Brown ◽  
Michael Chonin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Fatigue Resistance ◽  
Electron Beam Melting ◽  
High Reliability ◽  
National Laboratory ◽  
Post Processing ◽  
Proof Stress ◽  
Β Phase ◽  
Microstructure And Mechanical Properties

Additively-manufactured Ti-6Al-4V (Ti64) exhibits high strength but in some cases inferior elongation to those of conventionally manufactured materials. Post-processing of additively manufactured Ti64 components is investigated to modify the mechanical properties for specific applications while still utilizing the benefits of the additive manufacturing process. The mechanical properties and fatigue resistance of Ti64 samples made by electron beam melting were tested in the as-built state. Several heat treatments (up to 1000 °C) were performed to study their effect on the microstructure and mechanical properties. Phase content during heating was tested with high reliability by neutron diffraction at Los Alamos National Laboratory. Two different hot isostatic pressings (HIP) cycles were tested, one at low temperature (780 °C), the other is at the standard temperature (920 °C). The results show that lowering the HIP holding temperature retains the fine microstructure (~1% β phase) and the 0.2% proof stress of the as-built samples (1038 MPa), but gives rise to higher elongation (~14%) and better fatigue life. The material subjected to a higher HIP temperature had a coarser microstructure, more residual β phase (~2% difference), displayed slightly lower Vickers hardness (~15 HV10N), 0.2% proof stress (~60 MPa) and ultimate stresses (~40 MPa) than the material HIP’ed at 780 °C, but had superior elongation (~6%) and fatigue resistance. Heat treatment at 1000 °C entirely altered the microstructure (~7% β phase), yield elongation of 13.7% but decrease the 0.2% proof-stress to 927 MPa. The results of the HIP at 780 °C imply it would be beneficial to lower the standard ASTM HIP temperature for Ti6Al4V additively manufactured by electron beam melting.

Study on the Oxidation Behavior of LPPS MCrAlY Coatings at High Temperature: Part II Coating Microstructure Development

2021 ◽  
Vol 1035 ◽  
pp. 584-590
Author(s):  
Kang Yuan ◽  
Zhao Ran Zheng
Keyword(s):  
High Temperature ◽  
Thermodynamic Simulation ◽  
Thermal Barrier ◽  
Microstructure Development ◽  
Temperature Oxidation ◽  
Bond Coats ◽  
Β Phase ◽  
Mcraly Coatings ◽  
Coating Microstructure ◽  
Simulation Results

MCrAlY can be used as bond coats for thermal barrier coatings (TBCs) with good ductility and excellent resistance against high temperature oxidation and hot corrosion. The behavior of the microstructure development in the MCrAlY coatings plays a key role on the oxidation resistance. In this paper, the microstructure in the coatings oxidized at 750~1100 °C was analyzed. The formation of the phases and their fraction were studied by comparing thermodynamic simulation results with the experimental observations. At higher temperatures (>1000 °C) β-to-γ’-to-γ phase transformation took place while at lower temperatures (<1000 °C) β phase would transfer to γ directly. The results show that the simulation can semi-quantitatively predict the microstructure formed in the coating.

scholarly journals Contribution of C−H⋯π Interactions to Polymorphic Transitions of a Molecular Crystal with Disordered Fragments

2021 ◽  
Author(s):  
Takuya Taniguchi ◽  
Daisuke Takagi ◽  
Toru Asahi
Keyword(s):  
High Temperature ◽  
Single Crystal ◽  
Intermolecular Interaction ◽  
Molecular Crystal ◽  
Interaction Analysis ◽  
Polymorphic Transition ◽  
Underlying Mechanism ◽  
Polymorphic Transitions ◽  
Π Interactions ◽  
Β Phase

Polymorphic transition is important for the functionality of crystalline materials. However, the underlying mechanism remains unclear, especially when the crystal structure contains disordered fragments. We report that C−H⋯π interactions play an important role in polymorphic transitions in a molecular crystal with disordered fragments. The crystal has three phases, namely the a (< -80°C), β (-80-40°C), and γ (< 40°C) phases, which are reversible through single-crystal-to-single-crystal transformation in association with temperature change. Disorder of bulky tert-butyl substituents appears at high-temperature in the β and γ phases. Intermolecular interaction analysis based on Hirshfeld surfaces and related fingerprint plots revealed that the proportion of π⋯π interactions decreased, while that of C−H⋯π interactions increased, at the transition from a to β phase. The proportion of C−H⋯π interactions also increased at the transition from β to γ phase, but continuously decreased in the β phase due to elevated temperature. Intermolecular interaction energies clarified the contribution of C−H⋯π interactions to the stability of high-temperature crystal β and γ phases via polymorphic transitions. Our results potentially lead to design molecular crystals with polymorphic transitions.

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