Galvanic corrosion is a type of corrosion which occurs when two different metals are in contact with each other and an electrolyte. Different metals will have different electric potentials when connected in this way. This difference creates an electric current through the electrolyte. In fact, the action of galvanic corrosion is the principle with which batteries are made. Of course this is also the reason batteries have a shelf life. The action of this circuit degrades whichever metal has a lower electric potential. This is described as being less noble, whereas the metal with the higher potential is more noble. The degradation of the less noble metal eventually gets to the point that the circuit is broken by the oxides and salts created by the corrosion. This is the reason not only for a battery’s eventual death, but also for the way it dies, slowly losing electric potential because the anode (lower potential metal or connection) is slowly destroyed by the action of galvanic corrosion.
Liberty Intercept Blog
I'm very excited about the movie The Martian. Clearly I am not alone; after its opening day it received high audience ratings and near-to-box-office-record receipts. Although that may be because of the self-selected group anticipating to see it on opening day, let me give you a few reasons why you should be excited too.Read More
To be clear, the difference between electronics and other electrical systems is that electronics include active components to control the flow of electricity, whereas non-electronic electrical systems use mechanical switches or relays. The development of the vacuum tube (the first active component invented) allowed for the creation of far more complex systems than was possible with prior technology. Then solid-state transistors allowed electronics to shrink to sizes unthinkable before. Certainly at this point it is trivial to say that electronics are ubiquitous in society today and will only continue to become more so in the coming years, all the way up to the singularity, at which point we will become our own technology. As electronics have developed through the years, they have been given increasingly more important tasks. From air traffic control to car computers to medical equipment to missile defense, systems which include electronics control and protect our lives everyday. Thus it is essential that we know how to maintain them, for which we must also know how they degrade.
Posted by Greg Spitz on Sep 16, 2015 8:24:00 AM
To begin, it must be said that while the term "rust" is defined as iron oxide and therefore rusting is something that can only happen to iron and iron alloys, asking whether or not aluminum "rusts" gets to an important question. Really the question is about corrosion but because aluminum is an element and not an alloy of iron, the question is more properly posed as "Does aluminum corrode?" Let's find out.
Chlorine is one of the most common elements found on Earth's crust. The name comes from the Greek word for light green, which is how the gas appears in elemental form. It has 17 protons and two stable isotopes giving it a standard atomic weight of 35.45, which makes chlorine the second lightest halogen. It also has the highest electron affinity of any element making it a very strong oxidizer. This means that chlorine will readily steal electrons from other elements. In fact the vast majority of chlorine found on Earth is in the form of the chloride anion (a chlorine atom which has already stolen an extra electron), which will form ionic compounds with many cations (like metals). It is in this form that humans are most familiar with chlorine, as in ionic compound sodium chloride, which we know of as table salt. Chloride ions are important to many chemical and industrial processes including the making of usable chlorine and sodium hydroxide, and desalination and testing of potable water.
We continue our coverage of the Boston Time Capsule with updates from our recent visit to the Museum of Fine Arts, exhibit showing what was discovered inside the second Capsule recovered. The interest in this Time Capsule has been highly documented by many world news organizations because two well-known American patriots, Paul Revere and Sam Adams, were involved. Photos we were allowed to take are shown below.
Posted by Elaine Spitz on Apr 10, 2015 9:12:00 AM
Posted by Elaine Spitz on Feb 23, 2015 2:22:00 PM
Cadmium, a naturally-occurring element, is one of several metallic coating materials which are electrochemically active and, therefore, used as sacrificial coatings to prevent corrosion. Typically they are applied to iron, steel, zinc, aluminum, and titanium alloys, as well.
Cadmium coatings are used on hardware that must be subjected to harsh environments, especially where good corrosion resistance to marine or salt-laden atmospheres is required. Cadmium coatings are often employed in shipbuilding applications because of their high resistance to sea salt, and also in railroad, and ordnance applications. In addition, cadmium coatings have good corrosion fatigue properties as well as resistance to stress corrosion cracking, making them valuable in protecting high strength steel fasteners utilized in the aircraft industry.Read More
Posted by Elaine Spitz on Feb 17, 2015 2:22:00 PM
All metals, rubber, paints, leather, and lesser plastics will corrode, especially in harsh environments, close to the ocean or in polluted climates, which are becoming more commonplace with many relatively-new industrialized nations spewing corrosive gases into the borderless atmosphere.
For the first time in the nearly forty year history of the IEEE Milestones program, the group gave four awards in one day to the same company. That company is of course Bell Labs, currently a subsidiary of Alcatel Lucent. President of Bell Labs Marcus Weldon (center of photo) was there to receive the four awards for communications theory and networks, wireless and satellite communications, digital signal processing and computing, and solid-state and optical devices.