The solution pH of minimum corrosive attack on aluminum goes down with increasing temperature. It is of the order of 6.5 at 50 C and 3 at 300 C. Corrosion in slightly alkaline solutions (pH 8.5) is more rapid than in neutral water at all temperatures.
The solution pH of minimum corrosive attack on aluminum goes down with increasing temperature. It is of the order of 6.5 at 50 C and 3 at 300 C. Corrosion in slightly alkaline solutions (pH 8.5) is more rapid than in neutral water at all temperatures.
That depends on the aluminum alloy and the environment. 2000- and 7000-series aluminum alloys tend to be corrosion-prone, but they’ll be very slow to corrode in a cold, dry desert. 5000-series aluminum alloys are pretty resistant to marine environments so they won’t corrode fast even on the ocean.
It’s hard to say. Corrosion is very sensitive to conditions: humidity, temperature, corrosive agent(s), alloy, impurities, etc. Even touching another metal can accelerate aluminum’s corrosion.
That depends on the aluminum alloy and the environment. 2000- and 7000-series aluminum alloys tend to be corrosion-prone, but they’ll be very slow to corrode in a cold, dry desert. 5000-series aluminum alloys are pretty resistant to marine environments so they won’t corrode fast even on the ocean.
It’s hard to say. Corrosion is very sensitive to conditions: humidity, temperature, corrosive agent(s), alloy, impurities, etc. Even touching another metal can accelerate aluminum’s corrosion.
No, because ‘acid’ is often part of the name of a substance, with no corresponding high acidity.
Example: DNA is Deoxy ribo Nucleic Acid.
Corrosive acidity could be thought of beginning under a pH of about 5, but then water, considered to be an ‘acid’ with a pH of just 7, is also corrosive for iron in the long run.
Of course, it depends on the material which is or is not corroded. Gold, for example, is not corroded even by strong hydrochloric acid, if oxidising nitric acid is not also present.
No, because ‘acid’ is often part of the name of a substance, with no corresponding high acidity.
Example: DNA is Deoxy ribo Nucleic Acid.
Corrosive acidity could be thought of beginning under a pH of about 5, but then water, considered to be an ‘acid’ with a pH of just 7, is also corrosive for iron in the long run.
Of course, it depends on the material which is or is not corroded. Gold, for example, is not corroded even by strong hydrochloric acid, if oxidising nitric acid is not also present.
Let me answer your question first with a question and then an a short explanation.
“corrosive” according to who?”
Corrosion and “rust” are widely seen as meaning the same thing. By that definition sea water is corrosive to iron and steel when hey are exposed to it or even near it. Ocean going ships (and the Golden Gate bridge) are constantly being painted with corrosion resistant paint. Sea water typically has a pH of about 8. But I think you are asking a different question.
There is a legal (regulatory) definition of “Corrosive” according to the EPA. Any liquid ( or any solid when added to water) that exhibits a pH of less than pH 2 or greater than pH 12.5 is classed as Corrosive for purposes of determining a Hazardous Waste (HW) [40 CFR 261.22]. This “corrosion” means the ability to “eat away” by chemical reaction most metals and (importantly) human tissue (skin). In almost all cases this is the threshold that makes the decision: measure the pH of the liquid. In almost all cases the decision is obvious - Most acid waste has a pH of about 1 or 0 (battery acid) and alkali waste has a pH of about 13 - 14 (discarded lye and all of its solutions). In 16 years of managing a medium university waste stream I never saw an acid waste with a pH of 1.99 or 2.01
In addition, California HW regulations also say this ( pH 12.5) and further define “corrosive” by referring to specific (described) corrosion lab tests on certain steel alloys, but I have never seen any sample that fit this criterion. I don’t know if any of this would class sea water as hazardous according to EPA. I never had occasion to need to find out.
Let me answer your question first with a question and then an a short explanation.
“corrosive” according to who?”
Corrosion and “rust” are widely seen as meaning the same thing. By that definition sea water is corrosive to iron and steel when hey are exposed to it or even near it. Ocean going ships (and the Golden Gate bridge) are constantly being painted with corrosion resistant paint. Sea water typically has a pH of about 8. But I think you are asking a different question.
There is a legal (regulatory) definition of “Corrosive” according to the EPA. Any liquid ( or any solid when added to water) that exhibits a pH of less than pH 2 or greater than pH 12.5 is classed as Corrosive for purposes of determining a Hazardous Waste (HW) [40 CFR 261.22]. This “corrosion” means the ability to “eat away” by chemical reaction most metals and (importantly) human tissue (skin). In almost all cases this is the threshold that makes the decision: measure the pH of the liquid. In almost all cases the decision is obvious - Most acid waste has a pH of about 1 or 0 (battery acid) and alkali waste has a pH of about 13 - 14 (discarded lye and all of its solutions). In 16 years of managing a medium university waste stream I never saw an acid waste with a pH of 1.99 or 2.01
In addition, California HW regulations also say this ( pH 12.5) and further define “corrosive” by referring to specific (described) corrosion lab tests on certain steel alloys, but I have never seen any sample that fit this criterion. I don’t know if any of this would class sea water as hazardous according to EPA. I never had occasion to need to find out.
When aluminum is exposed to alkaline conditions corrosion may occur, and when the oxide film is perforated locally, accelerated attack occurs because aluminum is attacked more rapidly than its oxide under alkaline conditions. The result is pitting.
When aluminum is exposed to alkaline conditions corrosion may occur, and when the oxide film is perforated locally, accelerated attack occurs because aluminum is attacked more rapidly than its oxide under alkaline conditions. The result is pitting.
The solution pH of minimum corrosive attack on aluminum goes down with increasing temperature. It is of the order of 6.5 at 50 C and 3 at 300 C. Corrosion in slightly alkaline solutions (pH 8.5) is more rapid than in neutral water at all temperatures.
The solution pH of minimum corrosive attack on aluminum goes down with increasing temperature. It is of the order of 6.5 at 50 C and 3 at 300 C. Corrosion in slightly alkaline solutions (pH 8.5) is more rapid than in neutral water at all temperatures.
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How long does aluminum take to corrode?
That depends on the aluminum alloy and the environment. 2000- and 7000-series aluminum alloys tend to be corrosion-prone, but they’ll be very slow to corrode in a cold, dry desert. 5000-series aluminum alloys are pretty resistant to marine environments so they won’t corrode fast even on the ocean.
It’s hard to say. Corrosion is very sensitive to conditions: humidity, temperature, corrosive agent(s), alloy, impurities, etc. Even touching another metal can accelerate aluminum’s corrosion.
How long does aluminum take to corrode?
That depends on the aluminum alloy and the environment. 2000- and 7000-series aluminum alloys tend to be corrosion-prone, but they’ll be very slow to corrode in a cold, dry desert. 5000-series aluminum alloys are pretty resistant to marine environments so they won’t corrode fast even on the ocean.
It’s hard to say. Corrosion is very sensitive to conditions: humidity, temperature, corrosive agent(s), alloy, impurities, etc. Even touching another metal can accelerate aluminum’s corrosion.
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No, because ‘acid’ is often part of the name of a substance, with no corresponding high acidity.
Example: DNA is Deoxy ribo Nucleic Acid.
Corrosive acidity could be thought of beginning under a pH of about 5, but then water, considered to be an ‘acid’ with a pH of just 7, is also corrosive for iron in the long run.
Of course, it depends on the material which is or is not corroded. Gold, for example, is not corroded even by strong hydrochloric acid, if oxidising nitric acid is not also present.
No, because ‘acid’ is often part of the name of a substance, with no corresponding high acidity.
Example: DNA is Deoxy ribo Nucleic Acid.
Corrosive acidity could be thought of beginning under a pH of about 5, but then water, considered to be an ‘acid’ with a pH of just 7, is also corrosive for iron in the long run.
Of course, it depends on the material which is or is not corroded. Gold, for example, is not corroded even by strong hydrochloric acid, if oxidising nitric acid is not also present.
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Let me answer your question first with a question and then an a short explanation.
“corrosive” according to who?”
Corrosion and “rust” are widely seen as meaning the same thing. By that definition sea water is corrosive to iron and steel when hey are exposed to it or even near it. Ocean going ships (and the Golden Gate bridge) are constantly being painted with corrosion resistant paint. Sea water typically has a pH of about 8.
But I think you are asking a different question.
There is a legal (regulatory) definition of “Corrosive” according to the EPA. Any liquid ( or any solid when added to water) that exhibits a pH of less than pH 2 or greater than pH 12.5 is classed as Corrosive for purposes of determining a Hazardous Waste (HW) [40 CFR 261.22]. This “corrosion” means the ability to “eat away” by chemical reaction most metals and (importantly) human tissue (skin). In almost all cases this is the threshold that makes the decision: measure the pH of the liquid. In almost all cases the decision is obvious - Most acid waste has a pH of about 1 or 0 (battery acid) and alkali waste has a pH of about 13 - 14 (discarded lye and all of its solutions). In 16 years of managing a medium university waste stream I never saw an acid waste with a pH of 1.99 or 2.01
In addition, California HW regulations also say this (pH 12.5) and further define “corrosive” by referring to specific (described) corrosion lab tests on certain steel alloys, but I have never seen any sample that fit this criterion. I don’t know if any of this would class sea water as hazardous according to EPA. I never had occasion to need to find out.
Thanks for your very esoteric question.
And Thanks for listening.
Let me answer your question first with a question and then an a short explanation.
“corrosive” according to who?”
Corrosion and “rust” are widely seen as meaning the same thing. By that definition sea water is corrosive to iron and steel when hey are exposed to it or even near it. Ocean going ships (and the Golden Gate bridge) are constantly being painted with corrosion resistant paint. Sea water typically has a pH of about 8.
But I think you are asking a different question.
There is a legal (regulatory) definition of “Corrosive” according to the EPA. Any liquid ( or any solid when added to water) that exhibits a pH of less than pH 2 or greater than pH 12.5 is classed as Corrosive for purposes of determining a Hazardous Waste (HW) [40 CFR 261.22]. This “corrosion” means the ability to “eat away” by chemical reaction most metals and (importantly) human tissue (skin). In almost all cases this is the threshold that makes the decision: measure the pH of the liquid. In almost all cases the decision is obvious - Most acid waste has a pH of about 1 or 0 (battery acid) and alkali waste has a pH of about 13 - 14 (discarded lye and all of its solutions). In 16 years of managing a medium university waste stream I never saw an acid waste with a pH of 1.99 or 2.01
In addition, California HW regulations also say this (pH 12.5) and further define “corrosive” by referring to specific (described) corrosion lab tests on certain steel alloys, but I have never seen any sample that fit this criterion. I don’t know if any of this would class sea water as hazardous according to EPA. I never had occasion to need to find out.
Thanks for your very esoteric question.
And Thanks for listening.
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Both very low pH (acidic) and very high pH (basic) are corrosive. Neutral pH is around 7.
Both very low pH (acidic) and very high pH (basic) are corrosive. Neutral pH is around 7.
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When aluminum is exposed to alkaline conditions corrosion may occur, and when the oxide film is perforated locally, accelerated attack occurs because aluminum is attacked more rapidly than its oxide under alkaline conditions. The result is pitting.
When aluminum is exposed to alkaline conditions corrosion may occur, and when the oxide film is perforated locally, accelerated attack occurs because aluminum is attacked more rapidly than its oxide under alkaline conditions. The result is pitting.
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