Related Experiment Video
Updated: Jun 19, 2026
04:56
In Vivo Electrophysiological Measurement of the Rat Ulnar Nerve with Axonal Excitability Testing
Published on: February 6, 2018
THE EFFECTS OF POLARIZATION UPON THE STEEL WIRE-NITRIC ACID MODEL OF NERVE ACTIVITY.
1Department of Physiology, Washington University School of Medicine, St. Louis.
The Journal of General Physiology
|October 30, 2009
Summary
Steel wire passivation in nitric acid exhibits nerve-like reactivity. This electrochemical process involves alternating oxide coatings, suggesting a unique passivation mechanism distinct from simple oxide reduction.
Area of Science:
- Electrochemistry
- Materials Science
- Corrosion Science
Background:
- Passivation of steel in nitric acid is crucial for corrosion resistance.
- Understanding the electrochemical behavior of passivated metals is key to controlling their reactivity.
- Nerve-like phenomena in electrochemical systems offer insights into complex reaction dynamics.
Purpose of the Study:
- To investigate the active process of steel wire passivated by nitric acid under polarizing current.
- To characterize the potential changes and reactivity of passivated steel.
- To explore the mechanism behind the observed nerve-like reactivity.
Main Methods:
- Observation of active processes in passivated steel wire using a polarizing current.
- Potential measurements recorded via cathode ray oscillograph.
- Analysis of potential drop distribution between anode and cathode.
Main Results:
- Potential drop is predominantly at the anode (80%) in passive steel wire.
- The transition from active to passive states is abrupt, with a near-rectangular potential curve.
- Refractory state duration changes at anode and cathode, mimicking nerve behavior.
- Passivated soft iron wire exhibits rhythmic activity and sharp alternations between oxide coatings and clean surfaces.
Conclusions:
- The observed reactivity is not due to partial oxide reduction.
- Nerve-like reactivity may involve an alternation between two protective oxide coatings.
- Passivation is an electrochemical protection mechanism followed by electrode-solution equilibrium.
- The formation and dissolution of oxide layers play a critical role in the passivation dynamics.
Related Concept Videos
01:24Local Anesthetics: Differential Sensitivity of Nerve Fibers
Local anesthetics (LAs) block the sodium channels of nerve trunks, sensory nerve endings, and neuromuscular junctions. Although LAs can block all kinds of nerves, the sensitivity of nerve fibers differs according to nerve types and structures. LAs are known to block myelinated fibers faster than unmyelinated ones. Also, they block pain or sensory neurons at low concentrations without affecting the motor neurons involved in muscle contractions. This helps relieve labor pain without affecting the...
01:30The Electrical Double Layer
In the region where two bulk phases meet, an intricate electric charge distribution arises due to charge transfer, ion adsorption, molecular orientation, and charge distortion. This complex distribution is commonly referred to as the electrical double layer.When a solid electrode interfaces with ions in an electrolyte solution, the speed of electron transfer dictates the rates of oxidation and reduction. The electrode acquires a charge through the escape of atoms into the solution as cations or...
01:30Processes at Electrodes
The electrode interacts with ions in the electrolyte solution at its interface. The rate of oxidation and reduction depends on the speed at which electrons can transfer through this interface. As ions attach to or leave the electrode surface, the electrode acquires a charge, and an electrical potential forms across the interface, making the process more difficult to reach equilibrium. The charge on the electrode affects the local ion concentrations in the solution, though thermal motion...
01:15Charging Conductors By Induction
The Earth is a good conductor of electricity, and it is so big that it can be considered an infinite source or sink of charges. It can easily exchange charges with any matter.
Generally, conductors like metals do not allow any excess charge to be present on them. Any excess charge added to metals easily flows away, for example, when a metal is placed on the Earth. This process is called earthing.
However, conductors can be charged by a process called induction. For example, consider charging a...
Generally, conductors like metals do not allow any excess charge to be present on them. Any excess charge added to metals easily flows away, for example, when a metal is placed on the Earth. This process is called earthing.
However, conductors can be charged by a process called induction. For example, consider charging a...