scholarly journals Effects of Anodizing Conditions on Thermal Properties of Al 20XX Alloys for Aircraft

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 433
Author(s):  
Junghyun Park ◽  
Kyeongsik Son ◽  
Junghoon Lee ◽  
Donghyun Kim ◽  
Wonsub Chung
Keyword(s):  
Sulfuric Acid ◽  
Heat Dissipation ◽  
Digital Camera ◽  
High Hardness ◽  
Laser Flash ◽  
Mixed Acid ◽  
Aerospace Applications ◽  
Laser Flash Analysis ◽  
Ft Ir ◽  
Optimized Conditions

Anodizing was applied to improve the heat dissipation performance of aluminum (Al) alloys, by forming an oxide layer, such that they could be employed in aerospace applications. The methods employed were hard sulfuric acid (high hardness), soft sulfuric acid (low hardness), boric-sulfuric mixed acid, tin-sulfuric mixed acid, and chromic acid solutions. Each process was completed under optimized conditions. The surface morphology was observed using field emission scanning electron microscopy (FE-SEM) and a digital camera. For the determination of thermal performance, Fourier transform infrared spectroscopy (FT-IR) was used to measure the emissivity at 50 °C, and laser flash analysis (LFA) was utilized to analyze the thermal diffusivity at room temperature to 300 °C. The radiative property of metals is often ignored because of their low emissivity, however, in this research, the emissivity of the metal oxides was found to be higher than that of bare metal series. This study improved the heat dissipation properties by oxidization of Al via the anodizing process.

scholarly journals Heat Dissipation in Epoxy/Amine-Based Gradient Composites with Alumina Particles: A Critical Evaluation of Thermal Conductivity Measurements

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1131 ◽  
Author(s):  
Matthias Morak ◽  
Philipp Marx ◽  
Mario Gschwandl ◽  
Peter Filipp Fuchs ◽  
Martin Pfost ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Dissipation ◽  
Critical Evaluation ◽  
Laser Flash ◽  
Element Analysis ◽  
Epoxy Amine ◽  
Alumina Particles ◽  
Laser Flash Analysis ◽  
Key Aspects ◽  
Guarded Heat Flow Meter

Abstract: For the design of the next generation of microelectronic packages, thermal management is one of the key aspects and must be met by the development of polymers with enhanced thermal conductivity. While all polymer classes show a very low thermal conductivity, this shortcoming can be compensated for by the addition of fillers, yielding polymer-based composite materials with high thermal conductivity. The inorganic fillers, however, are often available only in submicron- and micron-scaled dimensions and, consequently, can sediment during the curing reaction of the polymer matrix. In this study, an epoxy/amine resin was filled with nano- and submicron-scaled alumina particles, yielding a gradient composite. It was found that the thermal conductivity according to laser flash analysis of a sliced specimen ranged from 0.25 to 0.45 W·m−1·K−1 at room temperature. If the thermal conductivity of an uncut specimen was measured with a guarded heat flow meter, the ‘averaged’ thermal conductivity was measured to be only 0.25 W·m−1·K−1. Finite element analysis revealed that the heat dissipation through a gradient composite was of intermediate speed in comparison with homogeneous composites exhibiting a non-gradient thermal conductivity of 0.25 and 0.45 W·m−1·K−1.

scholarly journals Enhanced Thermal Conductivity of Silicone Composites Filled with Few-Layered Hexagonal Boron Nitride

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2072
Author(s):  
Wei-Cheng Cheng ◽  
Yi-Ting Hsieh ◽  
Wei-Ren Liu
Keyword(s):  
Thermal Conductivity ◽  
Boron Nitride ◽  
Heat Dissipation ◽  
Hexagonal Boron Nitride ◽  
Low Cost ◽  
Laser Flash ◽  
Force Microscopy ◽  
Surface Areas ◽  
Laser Flash Analysis ◽  
Surface Morphologies

In this study, we demonstrate the use of silicone/few-layered hexagonal boron nitride (FL-hBN) composites for heat dissipation applications. FL-hBN is synthesized via a green, facile, low-cost and scalable liquid exfoliation method using a jet cavitation process. The crystal structures, surface morphologies and specific surface areas of pristine h-BN and FL-hBN were characterized by XRD, SEM, TEM and AFM (atomic force microscopy). The results confirmed that FL-hBN with a thickness of ~4 nm was successfully obtained from the exfoliation process. In addition, we introduced both pristine h-BN and FL-hBN into silicone with different ratios to study their thermal properties. The results of the laser flash analysis indicate that the silicon/FL-hBN composite exhibited a higher thermal conductivity than that of the silicone/h-BN composite. With the optimal loading content of 30 wt.% FL-hBN content, the thermal conductivity of the composite could be enhanced to 230%, which is higher than that of silicone/h-BN (189%). These results indicate that jet cavitation is an effective and swift way to obtain few-layered hexagonal boron nitride that could effectively enhance the thermal conductivity of silicone composites.

Physical, Chemical, and Crystallographic Characterization of Anodic Coatings on High Strength Aluminum Base Alloys

1976 ◽  
Vol 34 ◽  
pp. 636-637
Author(s):  
R. E. Herfert ◽  
N. T. McDevitt
Keyword(s):  
Sulfuric Acid ◽  
Salt Spray ◽  
High Strength ◽  
Environmental Stability ◽  
Anodic Films ◽  
Sodium Dichromate ◽  
Corrosion Resistant ◽  
Aerospace Applications ◽  
Bond Strengths ◽  
Adhesive Bonded Joints

Durability of adhesive bonded joints in moisture and salt spray environments is essential to USAF aircraft. Structural bonding technology for aerospace applications has depended for many years on the preparation of aluminum surfaces by a sulfuric acid/sodium dichromate (FPL etch) treatment. Recently, specific thin film anodizing techniques, phosphoric acid, and chromic acid anodizing have been developed which not only provide good initial bond strengths but vastly improved environmental durability. These thin anodic films are in contrast to the commonly used thick anodic films such as the sulfuric acid or "hard" sulfuric acid anodic films which are highly corrosion resistant in themselves, but which do not provide good initial bond strengths, particularly in low temperature peel.The objective of this study was to determine the characteristics of anodic films on aluminum alloys that make them corrosion resistant. The chemical composition, physical morphology and structure, and mechanical properties of the thin oxide films were to be defined and correlated with the environmental stability of these surfaces in humidity and salt spray. It is anticipated that anodic film characteristics and corrosion resistance will vary with the anodizing processing conditions.

Gallium Arsenide Integrated Circuits Decapsulation Technique Using Mixed Acid Chemistry For Die-Level Failure Analysis

2018 ◽  
Author(s):  
Harold Jeffrey M. Consigo ◽  
Ricardo S. Calanog ◽  
Melissa O. Caseria
Keyword(s):  
Gallium Arsenide ◽  
Sulfuric Acid ◽  
Nitric Acid ◽  
Integrated Circuits ◽  
Failure Analysis ◽  
Mixed Acid ◽  
Optimum Parameters ◽  
Plastic Package ◽  
Fuming Nitric Acid ◽  
Concentrated Sulfuric Acid

Abstract Gallium Arsenide (GaAs) integrated circuits have become popular these days with superior speed/power products that permit the development of systems that otherwise would have made it impossible or impractical to construct using silicon semiconductors. However, failure analysis remains to be very challenging as GaAs material is easily dissolved when it is reacted with fuming nitric acid used during standard decapsulation process. By utilizing enhanced chemical decapsulation technique with mixture of fuming nitric acid and concentrated sulfuric acid at a low temperature backed with statistical analysis, successful plastic package decapsulation happens to be reproducible mainly for die level failure analysis purposes. The paper aims to develop a chemical decapsulation process with optimum parameters needed to successfully decapsulate plastic molded GaAs integrated circuits for die level failure analysis.

scholarly journals PULsE: An open-source software for laser flash analysis

2020 ◽  
Vol 6 ◽  
pp. 100044
Author(s):  
Artem Lunev ◽  
Vadim Zborovskii ◽  
Teymur Aliev ◽  
Robert Heymer ◽  
Olga Vilkhivskaya
Keyword(s):  
Open Source ◽  
Open Source Software ◽  
Laser Flash ◽  
Laser Flash Analysis

Zinc carbonate recovery from brass melting slag

2021 ◽  
Vol 98 ◽  
pp. 14-18
Author(s):  
Thao Nguyen Thi ◽  
◽  
Nam Pham Ky ◽  
Ngoc Tran Vu Diem
Keyword(s):  
Sulfuric Acid ◽  
High Purity ◽  
Room Temperature ◽  
Ph Value ◽  
Zinc Carbonate ◽  
Leaching Solution ◽  
Optimized Conditions ◽  
Melting Slag

Brass melting slag (20.38 wt.% Zn) was leached in sulfuric acid with concentration of (50 + 80) g/l H2SO4, leaching temperature of (30 + 60) °C for (30 + 120) min. The optimized conditions for 94.16% Zn extraction from brass melting slag were found as 70 g/l H2SO4, room temperature and 90 min. The leaching solution was purified by removal of Fe through Fe(OH)3 precipitation when adding ZnO to adjust pH value of 5. The solution was continuously cemented by Zn metal at 60 °C for 60 min to obtain Cu metal with high purity of 99 wt.% Cu. The purified solution with 37.64 g/l Zn was modified by Na2C03 to have pH value of about 6 and precipitation of ZnC03 (94.14 %).

scholarly journals Bach Adsorption Study for the Extraction of Silver Ions by Hydrazone Compounds from Aqueous Solution

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Abdussalam Salhin Mohamad Ali ◽  
Norfarhah Abdul Razak ◽  
Ismail Ab Rahman
Keyword(s):  
Metal Ions ◽  
Sol Gel ◽  
Silver Ions ◽  
Transition Metal Ions ◽  
Practical Applications ◽  
Compound C ◽  
Ft Ir ◽  
Sorbent Materials ◽  
Optimized Conditions ◽  
Sorption Characteristics

Sorbent materials based on a hydrazone Schiff base compound, C14H11BrN4O4, were prepared either by immobilizing the ligand into sol-gel (SG1) or bonding to silica (SG2). The sorbent materials were characterized by FT-IR, EDX, SEM, TEM, and TGA. The sorption characteristics of a matrix of eight transition metal ions (Ag+, Cu2+, Co2+, Ni2+, Fe3+, Pb2+, Zn2+, and Mn2+) using batch method were studied. Several key parameters that affected the extraction efficiency such as pH, contact time, metal ions concentration, and gel size (for SGl) were investigated and optimized. Under the optimized conditions, the physically immobilized hydrazone sorbent (SG1) exhibits highest selectivity towards Ag+ions, while the chemically bonded hydrazone sorbent (SG2) exhibits high extraction for all metal ions tested. However, for practical applications such as the removal and preconcentration of Ag+, the physically immobilized sorbent (SG1) is preferred.

scholarly journals Catalytic condensation of phenol with formaldehyde into BPF on recyclable anchoring sulfuric acid

2020 ◽  
Vol 213 ◽  
pp. 01003
Author(s):  
Hui Li ◽  
Xi Cao ◽  
Huiting He ◽  
Jian Liu ◽  
Weijian Xiang ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Solid Acid Catalyst ◽  
Acid Catalyst ◽  
Catalytic Performance ◽  
Significant Loss ◽  
High Yield ◽  
Element Analysis ◽  
Simple Filtration ◽  
Ft Ir ◽  
The Mind

A novel solid-acid catalyst (PVC-EDA-SO4H) based on polyvinyl chloride (PVC) were prepared after amination of Ethylenediamine (EDA) and anchorage of sulfuric acid. The as-prepared catalyst was characterized by FT-IR, Element analysis, Chemical titration and Thermal analysis, the results indicated that the sulfuric acid was successfully anchored on PVC. The PVC-EDA-SO4H showed excellent catalytic performance for the synthesis of bisphenol F, and achieved almost high yield and selectivity (94%) of BPF under the mind reaction conditions. Meanwhile, exhibited excellent reusability without the significant loss after six cycles via simple filtration.

scholarly journals Enzymatic Extraction, Purification, and Characterization of Polysaccharides from Penthorum chinense Pursh: Natural Antioxidant and Anti-Inflammatory

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Li-mei Lin ◽  
Ling-jia Zhao ◽  
Jing Deng ◽  
Su-hui Xiong ◽  
Jie Tang ◽  
...  
Keyword(s):  
Radical Scavenging ◽  
Steepest Ascent ◽  
Penthorum Chinense Pursh ◽  
Ft Ir ◽  
Experimental Yield ◽  
Burman Design ◽  
Anti Inflammatory ◽  
Penthorum Chinense ◽  
Optimized Conditions ◽  
Plackett Burman Design

Penthorum chinense Pursh (PCP) is a kind of functional food or medicine for liver protection. In the present work, Plackett-Burman design, steepest ascent method, and response surface methodology (RSM) were employed to obtain maximum total sugar yield. The experimental yield of 6.91% indicated a close agreement with the predicted yield of 7.00% of the model under optimized conditions. The major polysaccharide fraction (PCPP-1a) from PCPP was purified and identified as acidic polysaccharides with a high content of uronic acid (FT-IR, UV, HPGPC). PCPP had similar monosaccharide profile with PCPP-1a but was rich in galacturonic acid (HPLC). Both of PCPP and PCPP-1a possessed strong hydroxyl radical scavenging, DPPH radical scavenging, and Fe2+ chelating activities. Moreover, they were revealed to show strong anti-inflammatory activities by inhibiting NO, TNF-α, and IL-1β release compared to LPS treatment in RAW264.7 cells. These data suggest that the polysaccharides from PCP could be potential natural products for treating ROS and inflammatory-related diseases.

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