Impurity Diffusion in Single Crystal Aluminium Oxide

1997 ◽  
Vol 143-147 ◽  
pp. 1207-1212 ◽  
Author(s):  
E.G. Moya ◽  
F. Moya ◽  
D. Juvé ◽  
C. Grattepain
Keyword(s):  
Single Crystal ◽  
Aluminium Oxide ◽  
Impurity Diffusion

The Influence of Bracket Material, Ligation Force and Wear on Frictional Resistance of Orthodontic Brackets

1993 ◽  
Vol 20 (2) ◽  
pp. 109-115 ◽  
Author(s):  
O. Keith ◽  
S. P. Jones ◽  
E. H. Davies
Keyword(s):  
Stainless Steel ◽  
Abrasive Wear ◽  
Single Crystal ◽  
Wear Debris ◽  
Aluminium Oxide ◽  
Frictional Resistance ◽  
Material Force ◽  
Orthodontic Bracket ◽  
Ceramic Brackets ◽  
Ceramic Bracket

Planar static frictional phenomena were investigated for two types of ceramic and one type of stainless steel orthodontic bracket against rectangular stainless steel archwire. The brackets studied were ‘Starfire’ (single crystal aluminium oxide), ‘Allure III’ (polycrystalline aluminium oxide), and ‘Dentaurum’ (stainless steel). The investigative parameters were: bracket material, force of ligation and whether the brackets were new or ‘worn’. Without exception, both types of ceramic bracket produced greater frictional resistance than the stainless steel brackets throughout testing. At a ligation force of 500 g, the Starfire bracket gave the greatest frictional resistance. At ligation forces of 200 and 50 g, the greatest frictional resistance was seen with Allure III. After a period of simulated wear, frictional resistance of Starfire tended to increase at the greatest ligation load while that of both ceramics decreased slightly at the two lower ligation loads. The ceramic brackets caused abrasive wear of the archwire surfaces and the consequent wear debris may have contributed to the changes in frictional resistance seen with Starfire and Allure III. Dentaurm brackets produced minimal frictional resistance in any test and negligible change with wear.

scholarly journals Impurity diffusion in ion implanted AlN layers on sapphire substrates by thermal annealing

2022 ◽  
Author(s):  
hironori okumura ◽  
Yasuhiro Watanabe ◽  
Tomohiko Shibata ◽  
Kohei Yoshizawa ◽  
Akira Uedono ◽  
...  
Keyword(s):  
Single Crystal ◽  
Thermal Annealing ◽  
Annealing Temperature ◽  
Electrical Conductance ◽  
Impurity Diffusion ◽  
Magnesium Ions ◽  
Sapphire Substrates ◽  
Silicon Implantation ◽  
Oxygen Concentrations ◽  
Ion Implanted

Abstract We report on impurity diffusion in ion implanted AlN layers after thermal annealing. Silicon, tin, germanium, and magnesium ions were implanted into single-crystal AlN layers grown on sapphire substrates. By annealing at 1600oC, silicon and magnesium atoms were diffused in the AlN layer, while less change was observed in the distribution of germanium atoms. Silicon implantation introduced vacancy-related defects. By annealing at temperatures over 1300oC, the vacancy-related defects were reduced, while oxygen atoms were diffused from the substrate due to sapphire decomposition. We reproducibly achieved silicon-implanted AlN layers with electrical conductance by controlling the annealing temperature and distribution of silicon and oxygen concentrations.

Tracer impurity diffusion in single-crystal rutile (TiO2−x)

1985 ◽  
Vol 46 (11) ◽  
pp. 1267-1283 ◽  
Author(s):  
Jun Sasaki ◽  
N.L. Peterson ◽  
K. Hoshino
Keyword(s):  
Single Crystal ◽  
Impurity Diffusion ◽  
Rutile Tio2

Tungsten-series impurity diffusion in single-crystal tungsten

1984 ◽  
Vol 30 (4) ◽  
pp. 1788-1796 ◽  
Author(s):  
N. K. Arkhipova ◽  
S. M. Klotsman ◽  
I. P. Polikarpova ◽  
G. N. Tatarinova ◽  
A. N. Timofeev ◽  
...  
Keyword(s):  
Single Crystal ◽  
Impurity Diffusion

A Preparation of High Resolution Standards for Electron Microscopy. Part II

1971 ◽  
Vol 29 ◽  
pp. 160-161
Author(s):  
Akira Tanaka ◽  
David F. Harling
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Carbon Black ◽  
Single Crystal ◽  
Dark Field ◽  
Graphitized Carbon Black ◽  
Graphitized Carbon ◽  
Dark Field Imaging ◽  
Crystal Films ◽  
Micro Holes

In the previous paper, the author reported on a technique for preparing vapor-deposited single crystal films as high resolution standards for electron microscopy. The present paper is intended to describe the preparation of several high resolution standards for dark field microscopy and also to mention some results obtained from these studies. Three preparations were used initially: 1.) Graphitized carbon black, 2.) Epitaxially grown particles of different metals prepared by vapor deposition, and 3.) Particles grown epitaxially on the edge of micro-holes formed in a gold single crystal film.The authors successfully obtained dark field micrographs demonstrating the 3.4Å lattice spacing of graphitized carbon black and the Au single crystal (111) lattice of 2.35Å. The latter spacing is especially suitable for dark field imaging because of its preparation, as in 3.), above. After the deposited film of Au (001) orientation is prepared at 400°C the substrate temperature is raised, resulting in the formation of many square micro-holes caused by partial evaporation of the Au film.

Structure of Palladium Single-Crystal Films Prepared by Flash Evaporation onto (001) NaCl Substrates

1970 ◽  
Vol 28 ◽  
pp. 456-457
Author(s):  
L. E. Murr ◽  
G. Wong
Keyword(s):  
Single Crystal ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
High Rate ◽  
Flash Evaporation ◽  
Optimum Load ◽  
Single Crystal Films ◽  
Crystal Films ◽  
A Current

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.

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