Corrosion of Painted Metals—A Review

CORROSION ◽  
1982 ◽  
Vol 38 (7) ◽  
pp. 374-383 ◽  
Author(s):  
Henry Leidheiser
Keyword(s):  
Interfacial Region ◽  
Wet Adhesion ◽  
Filiform Corrosion ◽  
Cathodic Delamination

Abstract Seven types of corrosion and precorrosion of painted metals are reviewed: blistering, early rusting, flash rusting, anodic undermining, filiform corrosion, cathodic delamination, and wet adhesion. The importance of the nature of the interfacial region between the coating and the metal is emphasized. Ten unsolved problems are described.

Delamination of Poylmer Coatings from Metal Substrates: Submicroscopic and Molecular Aspects

2002 ◽  
Vol 734 ◽  
Author(s):  
M. Rohwerder ◽  
E. Hornung ◽  
Xing-Wen Yu
Keyword(s):  
Suitable Model ◽  
Kelvin Probe ◽  
Scanning Kelvin Probe ◽  
Mesoscopic Structure ◽  
Investigation Methods ◽  
Filiform Corrosion ◽  
First Results ◽  
Cathodic Delamination ◽  
Reaction Zones ◽  
Molecular Aspects

Delamination of organic coatings from metal surfaces can occur in a number of different ways, e.g. as pure cathodic delamination, as Filiform corrosion or a mixture of these. In fact, in most technical systems the pure cases are the exception and, of course, delamination is usually very slow. It has been shown that in fast delaminating systems the length scales may range between several 100 μm and several millimetres, while in systems which show slow delamination the reaction zones can be confined to submicroscopic distances [1]. This underlines the importance of investigation methods with submicroscopic resolution. As a very promising new technique Scanning Kelvin Probe Force Microscopy (SKPFM) was applied for the investigation of cathodic delamination and filiform corrosion on a submicroscopic scale [1, 2]. Indeed, these first investigations have shown that SKPFM gives basically the same information as the standard Scanning Kelvin Probe (SKP), but with a much improved resolution. It could be shown, for instance, that the extension of the reaction zone seems to be much narrower than would have to be assumed from the SKP measurements. Based on the knowledge about the different delamination types that was obtained from investigations with the standard SKP [3–12] the SKPFM should be the ideal tool to get information on the submicroscopic scale. However, SKPFM alone is not sufficient for revealing the underlying fundamental mechanisms; of even higher importance is the knowledge of the molecular and mesoscopic structure at the buried interface. In this paper a design for suitable model samples is proposed and first results are presented.

The influence of heat treatment on the fiber/matrix interface in a SiC-reinforced glassceramic

1988 ◽  
Vol 46 ◽  
pp. 742-743
Author(s):  
E. Bischoff ◽  
O. Sbaizero
Keyword(s):  
Heat Treatment ◽  
Aluminum Silicate ◽  
Lithium Aluminum ◽  
Interfacial Region ◽  
Specimen Preparation ◽  
Crack Wake ◽  
Pull Out ◽  
Annealed Material ◽  
Ultrasonic Drilling ◽  
Fiber Matrix Interface

Fiber or whisker reinforced ceramics show improved toughness and strength. Bridging by intact fibers in the crack wake and fiber pull-out after failure contribute to the additional toughness. These processes are strongly influenced by the sliding and debonding resistance of the interfacial region. The present study examines the interface in a laminated 0/90 composite consisting of SiC (Nicalon) fibers in a lithium-aluminum-silicate (LAS) glass-ceramic matrix. The material shows systematic changes in sliding resistance upon heat treatment.As-processed samples were annealed in air at 800 °C for 2, 4, 8, 16 and 100 h, and for comparison, in helium at 800 °C for 4 h. TEM specimen preparation of as processed and annealed material was performed with special care by cutting along directions having the fibers normal and parallel to the section plane, ultrasonic drilling, dimpling to 100 pm and final ionthinning. The specimen were lightly coated with Carbon and examined in an analytical TEM operated at 200 kV.

Preparation of Electron Transparent Metal-Matrix Composites

1968 ◽  
Vol 26 ◽  
pp. 334-335 ◽  
Author(s):  
M. R. Pinnel ◽  
A. Lawley
Keyword(s):  
Stainless Steel ◽  
Load Transfer ◽  
Volume Fraction ◽  
Steel Wire ◽  
Initial Step ◽  
Interfacial Region ◽  
Matrix Composites ◽  
Specific Test ◽  
The Matrix ◽  
The One

Numerous phenomenological descriptions of the mechanical behavior of composite materials have been developed. There is now an urgent need to study and interpret deformation behavior, load transfer, and strain distribution, in terms of micromechanisms at the atomic level. One approach is to characterize dislocation substructure resulting from specific test conditions by the various techniques of transmission electron microscopy. The present paper describes a technique for the preparation of electron transparent composites of aluminum-stainless steel, such that examination of the matrix-fiber (wire), or interfacial region is possible. Dislocation substructures are currently under examination following tensile, compressive, and creep loading. The technique complements and extends the one other study in this area by Hancock.The composite examined was hot-pressed (argon atmosphere) 99.99% aluminum reinforced with 15% volume fraction stainless steel wire (0.006″ dia.).Foils were prepared so that the stainless steel wires run longitudinally in the plane of the specimen i.e. the electron beam is perpendicular to the axes of the wires. The initial step involves cutting slices ∼0.040″ in thickness on a diamond slitting wheel.

A TEM study of the interface between organic matrix and aragonite in a biological hard tissue, nacre

1992 ◽  
Vol 50 (2) ◽  
pp. 1024-1025
Author(s):  
Jun Liu ◽  
Katie E. Gunnison ◽  
Mehmet Sarikaya ◽  
Ilhan A. Aksay
Keyword(s):  
Mechanical Properties ◽  
Ion Beam ◽  
Laminated Composite ◽  
Organic Matrix ◽  
Pearl Oyster ◽  
Interfacial Structure ◽  
Interfacial Region ◽  
Thin Sections ◽  
Organic Layers ◽  
Transmission Electron

The interfacial structure between the organic and inorganic phases in biological hard tissues plays an important role in controlling the growth and the mechanical properties of these materials. The objective of this work was to investigate these interfaces in nacre by transmission electron microscopy. The nacreous section of several different seashells -- abalone, pearl oyster, and nautilus -- were studied. Nacre is a laminated composite material consisting of CaCO3 platelets (constituting > 90 vol.% of the overall composite) separated by a thin organic matrix. Nacre is of interest to biomimetics because of its highly ordered structure and a good combination of mechanical properties. In this study, electron transparent thin sections were prepared by a low-temperature ion-beam milling procedure and by ultramicrotomy. To reveal structures in the organic layers as well as in the interfacial region, samples were further subjected to chemical fixation and labeling, or chemical etching. All experiments were performed with a Philips 430T TEM/STEM at 300 keV with a liquid Nitrogen sample holder.

The Reactive Formation of Diblock Copolymer at a Polymer/Polymer Interface and its Effect on Interfacial Structure

2000 ◽  
Vol 629 ◽  
Author(s):  
Jonathan S. Schulze ◽  
Timothy P. Lodge ◽  
Christopher W. Macosko
Keyword(s):  
Molecular Weight ◽  
Interfacial Structure ◽  
Root Mean Square Roughness ◽  
Radius Of Gyration ◽  
Interfacial Region ◽  
Force Microscopy ◽  
Amino Terminal ◽  
Polymer Interface ◽  
Atomic Force ◽  
Time Required

ABSTRACTThe reaction of perdeuterated amino-terminal polystyrene (dPS-NH2) with anhydrideterminal poly(methyl methacrylate) (PMMA-anh) at a PS/PMMA interface has been observed with forward recoil spectrometry (FRES). Bilayer samples were constructed by placing thin films of PS containing ∼8.5 wt % dPS-NH2 on a PMMA-anh layer. Significant reaction was observed only after annealing the samples at 174°C for several hours, a time scale at least two orders of magnitude greater than the time required for the dPS-NH2 chains to diffuse through the bulk PS layer. The topography of the interfacial region as copolymer formed was measured using atomic force microscopy (AFM). Roughening of the PS/PMMA interface was observed to varying degrees in all annealed samples. Furthermore, the extent of this roughening was found to depend on the PS matrix molecular weight. Reaction in the samples with a high molecular weight PS matrix resulted in a root mean square roughness approximately equal to the radius of gyration Rg of the copolymer. However, approximately twice as much roughening was observed in the low molecular weight PS matrix. This study reveals how the molecular weight of one of the phases can affect the rate of reaction at a polymer/polymer interface.

Super-Conducting Quantum Interference Device Technique: 3-D Localization of a Short within a Flip Chip Assembly

2001 ◽  
Author(s):  
Kendall Scott Wills ◽  
Omar Diaz de Leon ◽  
Kartik Ramanujachar ◽  
Charles P. Todd
Keyword(s):  
Form Factor ◽  
Failure Analysis ◽  
Time Domain ◽  
Quantum Interference ◽  
Flip Chip ◽  
Time Domain Reflectometry ◽  
Interfacial Region ◽  
Precise Localization ◽  
Super Conducting ◽  
Accuracy Of Measurement

Abstract In the current generations of devices the die and its package are closely integrated to achieve desired performance and form factor. As a result, localization of continuity failures to either the die or the package is a challenging step in failure analysis of such devices. Time Domain Reflectometry [1] (TDR) is used to localize continuity failures. However the accuracy of measurement with TDR is inadequate for effective localization of the failsite. Additionally, this technique does not provide direct 3-Dimenstional information about the location of the defect. Super-conducting Quantum Interference Device (SQUID) Microscope is useful in localizing shorts in packages [2]. SQUID microscope can localize defects to within 5um in the X and Y directions and 35um in the Z direction. This accuracy is valuable in precise localization of the failsite within the die, package or the interfacial region in flipchip assemblies.

scholarly journals Improvement of DC Breakdown Strength of the Epoxy/POSS Nanocomposite by Tailoring Interfacial Electron Trap Characteristics

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1298
Author(s):  
Farooq Aslam ◽  
Zhen Li ◽  
Guanghao Qu ◽  
Yang Feng ◽  
Shijun Li ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Breakdown Voltage ◽  
Breakdown Strength ◽  
Deep Level ◽  
Simulation Method ◽  
Neat Epoxy ◽  
Interfacial Region ◽  
Chemical Calculation ◽  
Oligomeric Silsesquioxane ◽  
Underlying Risk

To date, breakdown voltage is an underlying risk to the epoxy-based electrical high voltage (HV) equipment. To improve the breakdown strength of epoxy resin and to explore the formation of charge traps, in this study, two types of polyhedral oligomeric silsesquioxane (POSS) fillers are doped into epoxy resin. The breakdown voltage test is performed to investigate the breakdown strength of neat epoxy and epoxy/POSS composites. Electron traps that play an important role in breakdown strength are characterized by thermally stimulated depolarized current (TSDC) measurement. A quantum chemical calculation tool identifies the source of traps. It is found that adding octa-glycidyl POSS (OG-POSS) to epoxy enhances the breakdown strength than that of neat epoxy and epoxycyclohexyl POSS (ECH-POSS) incorporated epoxy. Moreover, side groups of OG-POSS possess higher electron affinity (EA) and large electronegativity that introduces deep-level traps into epoxy resin and restrain the electron transport. In this work, the origin of traps has been investigated by the simulation method. It is revealed that the functional properties of POSS side group can tailor an extensive network of deep traps in the interfacial region with epoxy and enhance the breakdown strength of the epoxy/POSS nanocomposite.

The state of coating–substrate interfacial region formed during TiO2 coating deposition by Gas Injection Magnetron Sputtering technique

2020 ◽  
Vol 398 ◽  
pp. 126092 ◽  
Author(s):  
Rafal Chodun ◽  
Katarzyna Nowakowska-Langier ◽  
Bartosz Wicher ◽  
Sebastian Okrasa ◽  
Roch Kwiatkowski ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Gas Injection ◽  
The State ◽  
Tio2 Coating ◽  
Interfacial Region ◽  
Coating Deposition
Sign in / Sign up

Export Citation Format

Share Document