In situ oxidation of Ni3Al Alloys

1988 ◽  
Vol 46 ◽  
pp. 542-543
Author(s):  
K. R. Lawless ◽  
J. V. Cathcart ◽  
E. A. Kenik
Keyword(s):  
Oxidation Process ◽  
Operating Temperature ◽  
Gas Analyzer ◽  
In Situ Oxidation ◽  
Fine Grained ◽  
Ordered Intermetallic ◽  
Oriented Polycrystalline ◽  
Residual Gas ◽  
Dynamic Embrittlement

Ni3Al is subject to dynamic embrittlement when tested in an oxidizing environment; whereas pre-oxidation under stress does not embrittle the alloy. In situ HVEM oxidation studies of several ordered intermetallic (LI2 structure) Ni3Al alloys with small additions of boron and hafnium are reported. AEM studies of the oxidized specimens were also made to fully characterize the microstructure. Specimens were annealed and then electropolished to penetration just prior to insertion in the hot stage of the HVEM. Oxidations were carried out at an oxygen pressure of 13-60 mPa at 750°C. Gas pressure and composition were monitored with a residual gas analyzer. Specimens raised to the operating temperature in the base vacuum (∼0.2 mPa) showed no indication of oxide in the diffraction pattern and were almost entirely free of dislocations.Many of the features of different stages of the oxidation process are shown in Fig. 1. After two minutes exposure to oxygen, a thin, fine-grained, oriented, polycrystalline region of primarily γ-Al2O3 developed at the thinnest regions of the foil (Region A in Fig. 1 and Fig. 2).

Hot stage study of γ →α Al2O3 transformations

1983 ◽  
Vol 41 ◽  
pp. 76-77
Author(s):  
Dennis Tucker ◽  
E. A. Kenik ◽  
John Hren
Keyword(s):  
Single Crystal ◽  
Sulfate Solution ◽  
Growth Characteristics ◽  
Gas Analyzer ◽  
General Growth ◽  
Nucleation Sites ◽  
Residual Gas ◽  
Α Al2o3 ◽  
Film Substrate

It has been observed in spherical A12O3 particles precipitated from sulfate solution that polycrystalline γ-Al2O3 forms at 900°C in air during calcination. Further heating brings about the transformation to single crystal α-Al2O3 particles at approximately 1100°C. This behavior has also been observed by other authors for the γ→α Al2O3 transformation. In order to determine the nucleation sites and trie general growth characteristics of these 1-10 μm diameter particles, it was decided to study the transformation in situ in a HVEM*.Powders were prepared after the method of Onoda and Curreri and placed on tungsten grids with a thin Pt film substrate. The powders were then heated in situ in a 1 meV microscope* equipped with a single tilt hot stage capable of achieving 1250°C and a residual gas analyzer.

High sulfur content microporous carbon coated sulfur composites synthesized via in situ oxidation of metal sulfide for high-performance Li/S batteries

2017 ◽  
Vol 5 (13) ◽  
pp. 6052-6059 ◽  
Author(s):  
Qian Wang ◽  
Zhen-Bo Wang ◽  
Chao Li ◽  
Da-Ming Gu
Keyword(s):  
Sulfur Content ◽  
Hollow Sphere ◽  
High Performance ◽  
Oxidation Process ◽  
Metal Sulfide ◽  
Microporous Carbon ◽  
In Situ Oxidation ◽  
High Sulfur Content ◽  
Carbon Coated

Microporous carbon coated sulfur composites with a double-hollow-sphere structure are prepared through anin situoxidation process.

Preparation SnO2 Nanolayer on Flexible Polyimide Substrates via Direct Ion-Exchange and in situ Oxidation Process

2011 ◽  
Vol 3 (3) ◽  
pp. 789-794 ◽  
Author(s):  
Guanghui Cui ◽  
Dezhen Wu ◽  
Shengli Qi ◽  
Shao Jin ◽  
Zhanpeng Wu ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Oxidation Process ◽  
In Situ Oxidation

Technology Status Review In Situ Oxidation

1999 ◽  
Author(s):  
VIRGINIA UNIV CHARLOTTESVILLE
Keyword(s):  
In Situ Oxidation

How Artefacts Do Leadership: A Ventriloquial Analysis

2021 ◽  
pp. 089331892199807
Author(s):  
Jonathan Clifton ◽  
Fernando Fachin ◽  
François Cooren
Keyword(s):  
Organizational Communication ◽  
Recent Work ◽  
Distributed Leadership ◽  
Network Theory ◽  
Actor Network Theory ◽  
Fine Grained ◽  
Naturally Occurring ◽  
Human Actors

To date there has been little work that uses fine-grained interactional analyses of the in situ doing of leadership to make visible the role of non-human as well as human actants in this process. Using transcripts of naturally-occurring interaction as data, this study seeks to show how leadership is co-achieved by artefacts as an in-situ accomplishment. To do this we situate this study within recent work on distributed leadership and argue that it is not only distributed across human actors, but also across networks that include both human and non-human actors. Taking a discursive approach to leadership, we draw on Actor Network Theory and adopt a ventriloquial approach to sociomateriality as inspired by the Montreal School of organizational communication. Findings indicate that artefacts “do” leadership when a hybrid presence is made relevant to the interaction and when this presence provides authoritative grounds for influencing others to achieve the group’s goals.

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