Simultaneous Correction of the iR Potential Drop during Potentiostatic Polarisation Measurements

1976 ◽  
Vol 11 (2) ◽  
pp. 78-79 ◽  
Author(s):  
P. Doig ◽  
P. E. J. Flewitt
Keyword(s):  
Potential Drop ◽  
Potentiostatic Polarisation ◽  
Polarisation Measurements

Corrosion of Electronic and Magnetic Devices and Materials

1996 ◽  
Vol 451 ◽  
Author(s):  
Gerald S. Frankel
Keyword(s):  
Thin Film ◽  
Failure Modes ◽  
Galvanic Corrosion ◽  
Potential Drop ◽  
Magnetic Devices ◽  
Disk Structure ◽  
Magnetic Layers ◽  
Ohmic Potential Drop ◽  
Corrosion Problem ◽  
Corrosion Susceptibility

ABSTRACTCorrosion of thin film structures commonly used in electronic and magnetic devices is discussed. Typical failure modes are presented, and galvanic corrosion is discussed in some detail since it is one common problem with such devices. A graphical explanation for the determination of the ohmic potential drop during galvanic corrosion is presented. The corrosion problem of thin film disks is shown to have changed during the past ten years owing to changes in disk structure. The corrosion susceptibility of two antiferromagnetic alloys used for exchange coupling to soft magnetic layers is discussed.

Improved Compliance Solutions for C(T), SE(B) and Clamped SE(T) Specimens Including Side-Grooves, Varying Thicknesses and 3-D Effects

2014 ◽  
Author(s):  
Gustavo Henrique B. Donato ◽  
Felipe Cavalheiro Moreira
Keyword(s):  
Crack Growth ◽  
Plane Strain ◽  
Plane Stress ◽  
Potential Drop ◽  
Crack Size ◽  
Growth Conditions ◽  
Size Estimation ◽  
Unloading Compliance ◽  
Integrity Assessments ◽  
Elastic Unloading

Fracture toughness and Fatigue Crack Growth (FCG) experimental data represent the basis for accurate designs and integrity assessments of components containing crack-like defects. Considering ductile and high toughness structural materials, crack growing curves (e.g. J-R curves) and FCG data (in terms of da/dN vs. ΔK or ΔJ) assumed paramount relevance since characterize, respectively, ductile fracture and cyclic crack growth conditions. In common, these two types of mechanical properties severely depend on real-time and precise crack size estimations during laboratory testing. Optical, electric potential drop or (most commonly) elastic unloading compliance (C) techniques can be employed. In the latter method, crack size estimation derives from C using a dimensionless parameter (μ) which incorporates specimen’s thickness (B), elasticity (E) and compliance itself. Plane stress and plane strain solutions for μ are available in several standards regarding C(T), SE(B) and M(T) specimens, among others. Current challenges include: i) real specimens are in neither plane stress nor plane strain - modulus vary between E (plane stress) and E/(1-ν2) (plane strain), revealing effects of thickness and 3-D configurations; ii) furthermore, side-grooves affect specimen’s stiffness, leading to an “effective thickness”. Previous results from current authors revealed deviations larger than 10% in crack size estimations following existing practices, especially for shallow cracks and side-grooved samples. In addition, compliance solutions for the emerging clamped SE(T) specimens are not yet standardized. As a step in this direction, this work investigates 3-D, thickness and side-groove effects on compliance solutions applicable to C(T), SE(B) and clamped SE(T) specimens. Refined 3-D elastic FE-models provide Load-CMOD evolutions. The analysis matrix includes crack depths between a/W=0.1 and a/W=0.7 and varying thicknesses (W/B = 4, W/B = 2 and W/B = 1). Side-grooves of 5%, 10% and 20% are also considered. The results include compliance solutions incorporating all aforementioned effects to provide accurate crack size estimation during laboratory fracture and FCG testing. All proposals revealed reduced deviations if compared to existing solutions.

Dynamic Crack Propagation in Single-Crystalline Silicon

1998 ◽  
Vol 539 ◽  
Author(s):  
T. Cramer ◽  
A. Wanner ◽  
P. Gumbsch
Keyword(s):  
Crack Propagation ◽  
Crystalline Silicon ◽  
Potential Drop ◽  
Tensile Tests ◽  
Terminal Velocity ◽  
Dynamic Crack Propagation ◽  
Dynamic Crack ◽  
Single Crystalline Silicon ◽  
Single Crystalline ◽  
Crack Propagation Velocity

AbstractTensile tests on notched plates of single-crystalline silicon were carried out at high overloads. Cracks were forced to propagate on {110} planes in a <110> direction. The dynamics of the fracture process was measured using the potential drop technique and correlated with the fracture surface morphology. Crack propagation velocity did not exceed a terminal velocity of v = 3800 m/s, which corresponds to 83%7 of the Rayleigh wave velocity vR. Specimens fractured at low stresses exhibited crystallographic cleavage whereas a transition from mirror-like smooth regions to rougher hackle zones was observed in case of the specimens fractured at high stresses. Inspection of the mirror zone at high magnification revealed a deviation of the {110} plane onto {111} crystallographic facets.

Improving the accuracy of the charge-sheet model for the long-channel metal-oxide semiconductor field-effect transistor

1987 ◽  
Vol 65 (8) ◽  
pp. 995-998
Author(s):  
N. G. Tarr
Keyword(s):  
Metal Oxide ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Inversion Layer ◽  
Potential Drop ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Analytic Approximation ◽  
Effect Transistor ◽  
Long Channel

It is shown that the accuracy of the charge-sheet model for the long-channel metal-oxide-semiconductor field-effect transistor can be improved by allowing for the small potential drop across the inversion layer, and by using a more accurate analytic approximation for the charge stored in the depletion region.

Improved version of potential drop crack monitor is introduced

1987 ◽  
Vol 9 (4) ◽  
pp. 248-248
Author(s):  
HOWDENMACHINERYLEAMINGTONSPA
Keyword(s):  
Potential Drop

The Measurement of the Thickness of Metal Walls from One Surface Only, by an Electrical Method

1938 ◽  
Vol 140 (1) ◽  
pp. 349-398 ◽  
Author(s):  
B. M. Thornton ◽  
W. M. Thornton
Keyword(s):  
Potential Drop ◽  
Engineering Industry ◽  
Steel Plates ◽  
Electrical Method ◽  
Order Of Accuracy ◽  
Iron Castings ◽  
Engine Cylinder ◽  
External Power ◽  
Metal Wall ◽  
Core Shift

There is a definite need in the engineering industry for an instrument which will determine accurately the thickness of a metal wall from one side only, and which is portable, robust, independent of external power supply, and easy to operate. The instrument described in the paper fulfils all these conditions. The method is essentially that of comparing the resistance of a metal wall under test with that of a similarly shaped wall of the same material, of which the thickness is known. Current, usually under 10 amp., is supplied by a 6- or 12-volt battery to two current contacts held against the wall and usually spaced 2 or 3 inches apart. The current in the circuit is adjusted by varying the rheostat or the number of cells of the small car-battery employed, until the very small potential drop indicated by the deflexion of a galvanometer connected to two potential contacts reaches a predetermined fixed value. From a calibration curve the thickness of the wall corresponding to the current registered by the ammeter is determined. The contacts are made on the plates whose thickness is to be measured by means of Evershed and Vignoles spring-controlled rotating points that were originally designed for a four-point method of working. The flexible leads from these, sometimes 100 but usually 30 feet long, are rubber-covered, and are connected to the circuit in the box by plugs and sockets. These are removed for transport and carried in a separate box. The instrument was originally designed for measuring the thickness of boiler tubes, and examples are given showing that its accuracy in this respect is within a few thousandths of an inch. It was found in practice that the instrument could be used to measure the thickness of mild steel plates up to 1·25 inches and of iron castings, up to 3 inches, with the same order of accuracy. It is also used for the measurement of engine cylinder walls to detect core shift. Examples of these are given in the paper. One notable case was that of the examination of a bank of superheater tubes in a boiler that had given much trouble due to the use of an unsuitable chain-grate stoker. Thinned tubes were at once detected and on being cut out the thicknesses indicated by the instrument were confirmed. Examples are given of the regular use of the instrument in determining the thickness of boiler and superheater tubes, ships' hull plates, tank wagons, and various iron castings that were accessible from one side only.

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