The impact of the mass density on selected optical and non-optical properties of oxide coatings

2014 ◽  
Vol 3 (1) ◽  
Author(s):  
Olaf Stenzel
Keyword(s):  
Silicon Dioxide ◽  
Zirconium Oxide ◽  
Hafnium Oxide ◽  
Optical Constants ◽  
Mass Density ◽  
Tantalum Pentoxide ◽  
Optical Coatings ◽  
Oxide Coatings ◽  
Numerous Experimental Data ◽  
The Impact

AbstractThe density of optical coatings is one of the most crucial material-related parameters in interference coating science and technology. It has an impact on the refractive index, the transparency range, and the mechanical stress of a coating material. This tutorial provides a background on the classical theory relating the coating density to the mentioned parameters. Simple models are presented that highlight the correlations between optical constants, stress, and shifting behavior of different oxide coatings. Comparison with the experiment is performed on the basis of numerous experimental data, which stem from hafnium oxide, zirconium oxide, tantalum pentoxide, and silicon dioxide.

scholarly journals Impact of the Ferroelectric Stack Lamination in Si Doped Hafnium Oxide (HSO) and Hafnium Zirconium Oxide (HZO) Based FeFETs: Toward High-Density Multi-Level Cell and Synaptic Storage

2021 ◽  
Vol 2 (3) ◽  
pp. 344-369
Author(s):  
Tarek Ali ◽  
Kati Kühnel ◽  
Ricardo Olivo ◽  
David Lehninger ◽  
Franz Müller ◽  
...  
Keyword(s):  
Zirconium Oxide ◽  
Hafnium Oxide ◽  
Ferroelectric Properties ◽  
Charge Trapping ◽  
Switching Speed ◽  
Columnar Grains ◽  
Lower Maximum ◽  
Si Doped ◽  
Multi Level ◽  
The Impact

A multi-level cell (MLC) operation as a 1–3 bit/cell of the FeFET emerging memory is reported by utilizing optimized Si doped hafnium oxide (HSO) and hafnium zirconium oxide (HZO) based on ferroelectric laminates. An alumina interlayer was used to achieve the thickness independent of the HSO and HZO-based stack with optimal ferroelectric properties. Various split thicknesses of the HSO and HZO were explored with lamination to increase the FeFET maximum memory window (MW) for a practical MLC operation. A higher MW occurred as the ferroelectric stack thickness increased with lamination. The maximum MW (3.5 V) was obtained for the HZO-based laminate; the FeFETs demonstrated a switching speed (300 ns), 10 years MLC retention, and 104 MLC endurance. The transition from instant switching to increased MLC levels was realized by ferroelectric lamination. This indicated an increased film granularity and a reduced variability through the interruption of ferroelectric columnar grains. The 2–3 bit/cell MLC levels and maximum MW were studied in terms of the size-dependent variability to indicate the impact of the ferroelectric area scaling. The impact of an alumina interlayer on the ferroelectric phase is outlined for HSO in comparison to the HZO material. For the same ferroelectric stack thickness with lamination, a lower maximum MW, and a pronounced wakeup effect was observed in HSO laminate compared to the HZO laminate. Both wakeup effect and charge trapping were studied in the context of an MLC operation. The merits of ferroelectric stack lamination are considered for an optimal FeFET-based synaptic device operation. The impact of the pulsing scheme was studied to modulate the FeFET current to mimic the synaptic weight update in long-term synaptic potentiation/depression.

scholarly journals Green Nanocoatings Based on the Deposition of Zirconium Oxide: The Role of the Substrate

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1043
Author(s):  
Vitor Bonamigo Moreira ◽  
Anna Puiggalí-Jou ◽  
Emilio Jiménez-Piqué ◽  
Carlos Alemán ◽  
Alvaro Meneguzzi ◽  
...  
Keyword(s):  
Zirconium Oxide ◽  
Active Sites ◽  
Modified Electrodes ◽  
Chemical Conversion ◽  
Ceramic Materials ◽  
Point Of View ◽  
Oxide Coatings ◽  
Alloying Element ◽  
Substrate Nature

Herein, the influence of the substrate in the formation of zirconium oxide monolayer, from an aqueous hexafluorozirconic acid solution, by chemical conversion and by electro-assisted deposition, has been approached. The nanoscale dimensions of the ZrO2 film is affected by the substrate nature and roughness. This study evidenced that the mechanism of Zr-EAD is dependent on the potential applied and on the substrate composition, whereas conversion coating is uniquely dependent on the adsorption reaction time. The zirconium oxide based nanofilms were more homogenous in AA2024 substrates if compared to pure Al grade (AA1100). It was justified by the high content of Cu alloying element present in the grain boundaries of the latter. Such intermetallic active sites favor the obtaining of ZrO2 films, as demonstrated by XPS and AFM results. From a mechanistic point of view, the electrochemical reactions take place simultaneously with the conventional chemical conversion process driven by ions diffusion. Such findings will bring new perspectives for the generation of controlled oxide coatings in modified electrodes used, as for example, in the construction of battery cells; in automotive and in aerospace industries, to replace micrometric layers of zinc phosphate by light-weight zirconium oxide nanometric ones. This study is particularly addressed for the reduction of industrial waste by applying green bath solutions without the need of auxiliary compounds and using lightweight ceramic materials.

scholarly journals The influence of bone quality on radiological outcome in 50 consecutive acetabular fractures treated with a pre-contoured anatomic suprapectineal plate

2021 ◽  
Author(s):  
Maximilian J. Hartel ◽  
Tareq Naji ◽  
Florian Fensky ◽  
Frank O. Henes ◽  
Darius M. Thiesen ◽  
...  
Keyword(s):  
Total Hip Arthroplasty ◽  
Bone Mass ◽  
Bone Quality ◽  
Hip Arthroplasty ◽  
Mass Density ◽  
Acetabular Fractures ◽  
Bone Mass Density ◽  
Radiological Outcome ◽  
Total Hip ◽  
The Impact

Abstract Purpose To investigate the range of indications of an anatomical-preshaped three-dimensional suprapectineal plate and to assess the impact of the bone mass density on radiologic outcomes in different types of acetabular fractures. Patients and methods A consecutive case series of 50 acetabular fractures (patient age 69 ± 23 years) treated with suprapectineal anatomic plates were analyzed in a retrospective study. The analysis included: Mechanism of injury, fracture pattern, surgical approach, need for additional total hip arthroplasty, intra- or postoperative complications, as well as bone mass density and radiological outcome on postoperative computed tomography. Results Most frequently, anterior column fracture patterns with and without hemitransverse components as well as associated two column fractures were encountered. The anterior intrapelvic approach (AIP) was used in 98% (49/50) of the cases as primary approach with additional utilization of the first window of the ilioinguinal approach in 13/50 cases (26%). Determination of bone density revealed impaired bone quality in 70% (31/44). Postoperative steps and gaps were significantly greater in this subgroup (p < 0.05). Fracture reduction quality for postoperative steps revealed anatomic results in 92% if the bone quality was normal and in 46% if impaired (p < 0.05). In seven cases (14%), the plate was utilized in combination with acute primary arthroplasty. Conclusion A preshaped suprapectineal plate provides good radiological outcomes in a variety of indications in a predominantly geriatric cohort. Impaired bone quality has a significantly higher risk of poor reduction results. In cases with extensive joint destruction, the combination with total hip arthroplasty was a valuable option.

scholarly journals Comprehensive Analytical Modelling of an Absolute pH Sensor

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5190
Author(s):  
Cristina Medina-Bailon ◽  
Naveen Kumar ◽  
Rakshita Pritam Singh Dhar ◽  
Ilina Todorova ◽  
Damien Lenoble ◽  
...  
Keyword(s):  
Silicon Dioxide ◽  
Numerical Experiments ◽  
Ph Sensor ◽  
Hafnium Dioxide ◽  
Matlab Code ◽  
Oxide Degradation ◽  
Depletion Width ◽  
Ion Activity ◽  
The Absolute ◽  
The Impact

In this work, we present a comprehensive analytical model and results for an absolute pH sensor. Our work aims to address critical scientific issues such as: (1) the impact of the oxide degradation (sensing interface deterioration) on the sensor’s performance and (2) how to achieve a measurement of the absolute ion activity. The methods described here are based on analytical equations which we have derived and implemented in MATLAB code to execute the numerical experiments. The main results of our work show that the depletion width of the sensors is strongly influenced by the pH and the variations of the same depletion width as a function of the pH is significantly smaller for hafnium dioxide in comparison to silicon dioxide. We propose a method to determine the absolute pH using a dual capacitance system, which can be mapped to unequivocally determine the acidity. We compare the impact of degradation in two materials: SiO2 and HfO2, and we illustrate the acidity determination with the functioning of a dual device with SiO2.

The Effect of Sodium Silicate Concentration on the Properties of the Coating Formed on Pure Zirconium by Microarc Oxidation Coating Technique

2012 ◽  
Vol 445 ◽  
pp. 637-642 ◽  
Author(s):  
Y. Gencer ◽  
M. Tarakci ◽  
S. Cengiz ◽  
K.O. Gunduz
Keyword(s):  
Surface Roughness ◽  
Sodium Silicate ◽  
Zirconium Oxide ◽  
Microarc Oxidation ◽  
Phase Content ◽  
Oxide Coatings ◽  
Silicate Concentration ◽  
X Ray ◽  
Pure Zirconium ◽  
Scanning Electron

In this study, zirconium oxide coatings were formed on pure zirconium by microarc oxidation technique with the electrolytes containing KOH and different amounts of sodium silicate (0-40 gr/lt) for the same coating duration of 2 hours. The microstructure, surface roughness, phase content and chemical composition of the coatings were characterized by using scanning electron microscopy, profilometery and X-ray diffractometry. It was found that the coatings on surface of zirconium consist of monoclinic ZrO2 (m-ZrO2) and tetragonal ZrO2 (t-ZrO2) phases and the addition and increasing sodium silicate concentration in the electrolyte increases amount of t-ZrO2 phase. The coatings were well adhered to Zr substrate with some cracks and porosities in the coating for all concentrations of sodium silicate. The coating thickness and surface roughness increased with sodium silicate concentration in the electrolyte. A glaze like Si rich structure and its increase with Si rate was evident in the outermost region of the coating.

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