Degradation of full aromatic polyamide NF membrane by sulfuric acid and hydrogen halides: Change of the surface/permeability properties

2019 ◽  
Vol 162 ◽  
pp. 1-11 ◽  
Author(s):  
Byung-Moon Jun ◽  
Hyung Kae Lee ◽  
You-In Park ◽  
Young-Nam Kwon
Keyword(s):  
Sulfuric Acid ◽  
Aromatic Polyamide ◽  
Hydrogen Halides ◽  
Surface Permeability

Effects of Hydrogen Halides On Anodic Polarization of Stainless Steel

CORROSION ◽  
1963 ◽  
Vol 19 (5) ◽  
pp. 180t-185t ◽  
Author(s):  
OLEN L. RIGGS
Keyword(s):  
Stainless Steel ◽  
Sulfuric Acid ◽  
Hydrogen Fluoride ◽  
Anodic Polarization ◽  
Potential Range ◽  
Halide Ions ◽  
Effective Protection ◽  
Hydrogen Halides ◽  
High Concentrations ◽  
Protection From Corrosion

Abstract The anodic polarization of stainless steel in 10 moles/liter sulfuric acid with various concentrations of HF, HCl and HBr has been investigated. At sufficiently high concentrations all of these hydrogen halide ions make it more difficult to establish and maintain passivity. They did not change the potential at which passivation was established, but they narrowed the passive potential range by increasing the potential at which breakdown occurred. They all accelerated the decay of passivity when the applied currents were interrupted. Effective protection from corrosion can still be obtained in these systems. In the presence of 1 mole per liter hydrogen fluoride, there was a substantial increase in current to maintain passivity without any corresponding loss of metal.

Preparation of Thin Cadmium Telluride Samples for Electron Microscope Studies

1974 ◽  
Vol 32 ◽  
pp. 548-549
Author(s):  
T. J. Magee ◽  
J. Peng ◽  
J. Bean
Keyword(s):  
Electron Microscope ◽  
Sulfuric Acid ◽  
Solid State ◽  
Sample Preparation ◽  
Cadmium Telluride ◽  
Potassium Dichromate ◽  
Optical Components ◽  
The Past ◽  
Solid State Devices

Cadmium telluride has become increasingly important in a number of technological applications, particularly in the area of laser-optical components and solid state devices, Microstructural characterizations of the material have in the past been somewhat limited because of the lack of suitable sample preparation and thinning techniques. Utilizing a modified jet thinning apparatus and a potassium dichromate-sulfuric acid thinning solution, a procedure has now been developed for obtaining thin contamination-free samples for TEM examination.

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.

Ultrastrong, Free-Standing and Large Nanofilms of Pyrenearamid

2019 ◽  
Author(s):  
Amalia Rapakousiou ◽  
Alejandro López-moreno ◽  
Belén Nieto-Ortega ◽  
M. Mar Bernal ◽  
Miguel A. Monclús ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Building Block ◽  
Aromatic Polyamide ◽  
Free Standing ◽  
Spatial Confinement ◽  
Polymeric Structure ◽  
Reduced Modulus ◽  
Organizational Arrangement ◽  
Polycyclic Aromatic ◽  
Nanoscale Building Block

We introduce poly(1,6-pyrene terephthalamide) polymer (PPyrTA) as an aromatic polyamide analogue of poly(p-phenylene terephthalamide) (PPTA), also known as Kevlar®. This work shows that the incorporation of polycyclic aromatic pyrene moieties improves drastically the mechanical properties of the polymeric structure, increasing elastic nanoindentation-determined modulus and hardness by factors of 1.9 and 4.3, respectively. Liquid deprotonated dispersions of PPyrTA nanofibers were used as nanoscale building block for producing large-surface, free-standing polymer macroscopic nanofilms. This 2D assembly leads to further significant improvements in reduced modulus and hardness (more than twice) compared to the starting polymer macroscale fibres, due to a better re-organizational arrangement of the PPyrTA nanofibers in the nanofilms, formed under 2D spatial confinement.

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