lead in pipes delivering the water to Flint’s citizens. In the late 1980s, the United States began to ban the use of lead pipes and solder. While this was a positive step forward, it could not change the misdeeds of the past. About 50% of homes in Flint still use lead service lines and other homes may have copper pipes with lead solder. This was not a problem when Flint used Detroit’s drinking water because Detroit added corrosion control chemicals such as a phosphate corrosion inhibitor to keep the lead out of the water that runs through the pipes. The phosphate would oxidize before the metal in the pipes would, galvanize and create a passivation layer, protecting the inside of the pipes from corrosion. When the Flint water treatment plant began treating the water from the Flint River, it opted out of the addition of these inhibitors. This causes the passivation layer to begin to dissolve, allowing mineral particles to flake off of the inside of the pipe, corrupting the water. The combination of this very corrosive water source and the lack of a corrosion inhibitor had dangerous results. When researchers from Virginia Tech investigated…
Most corrosion is an electrochemical reaction. Anything that affects the speed of the chemical reaction will in turn affect the amount of current flow, which will affect the rate of corrosion. The rate of corrosion is directly proportional to the amount of current in the electrochemical corrosion cell. If the current can be measured accurately, then an exact calculation of the metal loss can be made.
2.2.1 ELECTRICAL EFFECTS ON THE RATE OF CORROSION
Any issue that have an effect on the…
Study of Stress Corrosion Cracking (SCC) in
1. Introduction of Stress Corrosion Cracking
Stress Corrosion Cracking (SCC) is the growth of cracks with a under the combined
effects of a static stress and a specific chemical environment. All SCC failures
involve a macroscopic brittle performance, and the ductility of the material is reduced.
It is universally acknowledged that there is no single mechanism for stress corrosion
cracking (Ford, 1984). Stress…
modification of these properties pave the way for future research in inhibitor technology.
The inherent protection of metals and their alloys used in industry are of the upmost importance when it comes to longevity and reliability of structures. Many chemical compounds have been developed over the years that can inhibit the corrosion rate of metal alloys but cost effectiveness, toxicity, processibility and other factors limit the applications1. The need for new, eco-friendly and…
Stray current corrosion:
Stray current is the current which occurs when conductors are placed between high magnetic or electric fields. Presence of stray currents over the PCB surface can generate corrosion problems. The below figure 5 shows severe corrosion damage to micro wave module for 24 GHz. This equipment is built in controlled conditions where water condensation is possible. After few hours of use, severe corrosion was seen on the surface.
Figure 5. Stray current corrosion of a micro…
Making The Case For Metal Roofing: The Pros Outweigh The Cons By A Long Shot
What your roof is made of makes a big difference in how your home takes care of you and your family. For the following reasons, metal is, more often than not, the best choice for the job.
The Pros Of Metal Roofing
A metal roof is likely to remain functional and intact for as long as the home it covers does, resisting weather, rot, infestations and water all the while. According to one industry study, your…
Fig. 2 and Table 1 present the open circuit potential versus time curves and self-corrosion rate of Al, Alloy 1 and Alloy 2 electrodes in 2 M NaCl electrolyte, respectively. Corrosion rates were obtained by weight loss measurements in 2 M NaCl solution after 60 min. As seen in Table 1, the corrosion rate increases in the following order: Al ＜Alloy 1 ＜ Alloy 2. Fig. 2 indicates that open circuit potential of Alloy 1, 2 (especially Alloy2) is more negative than that of Al. It can be seen that the…
• Corrosion resistant
• Good tensile strength
• Good low and high temperature service
• Has a respectable friction coefficient
Stainless steel has a chromium-rich rust protective oxide thin film on the surface known as a passive layer, in which prevents corrosion by blocking oxygen diffusion to enter the passive layer and spreads rust into the internal material. As seen in Figure 1, stainless steel rather than forming a rust layer like…
What Is Slate Shingle Metal Roofing And Why Is It Better Than Slate Stone Tiles?
Slate shingle metal roofing is a roofing material made from metal and stamped to mimic the appearance of natural slate stone. A slate stone roof adds a touch of luxury to your home, but there are a few reasons why the metal version is superior. If you love the look of slate, you may want to look into slate shingle metal roofing. Here are a few reasons why.
Metal Slate Tiles Are Much Lighter Than Stone
Energy loss is a problem that engineers face. It is caused by friction in pipes which is also called the friction head loss and that happens because of viscosity and pipe wall friction. Energy loss also happens due to local losses which occur at valves and sharp bends. Local losses are also known as minor losses because their effect is normally small in long pipelines. To understand the relationship between Reynold’s number and friction factor, the pipe friction experiment has been…