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Properties of metals and their application

What is the corrosion process?

Task 3

Before you watch the movie „Rust: Prevention and treatment”, formulate a research question and hypotheses. During the screening pay attention to what happens to the nails on various dishes. What does it mean?

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Wykonaj ćwiczenie zgodnie z poleceniem. Analysis of the experiment: "Rust: Prevention and treatment”. Research question (Uzupełnij). Hypothesis (Uzupełnij). Observations (Uzupełnij). Conclusions (Uzupełnij).

Wykonaj ćwiczenie zgodnie z poleceniem. Analysis of the experiment: "Rust: Prevention and treatment”. Research question (Uzupełnij). Hypothesis (Uzupełnij). Observations (Uzupełnij). Conclusions (Uzupełnij).

Analysis of the experiment: "Rust: Prevention and treatment”

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Research question

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Hypothesis

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Observations

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Conclusions

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Film prezentuje instrukcję przeprowadzenia doświadczenie, w którym w czterech próbówkach umieszczono metalowe gwoździe. Do każdej z próbówek dodano inne substancje, aby sprawdzić, jak zareaguje metal. Na filmie widoczne są instrukcje tekstowe w języku angielskim. Place an iron nail in four test tubes. Fill one with regular tap water until the nail is submerged. Fill another with regular tap water and add half a spoonful of sodium chloride – regular table salt. Shake from side to side to ensure that sodium chloride fully dissolves. Fill the third test tube with recently boiled water and add a thin layer of oil. When water is being boiled, any dissolved oxygen is removed. The layer of oil prevents more oxygen from dissolving. In the last test tube add a spoonful of calcium chloride. Calcium chloride removes any moisture. In the first tube the nail is exsposed to oxygen and moisture. In the second test tube the nail is exposed to oxygen, moisture and salt. In the third test tube the nail is exposed to water. In the fourth test tube the nail is exposed to oxygen. All four test tubes are covered with rubber bung. After a couple of days you will find that the nails in the first and second test tubes have rusted. The nail in the second test tube has rusted more than the nail in the first test tube and the rust has likely flaked off. The nails in the thrid and fourth test tubes have not rusted.

Film prezentuje instrukcję przeprowadzenia doświadczenie, w którym w czterech próbówkach umieszczono metalowe gwoździe. Do każdej z próbówek dodano inne substancje, aby sprawdzić, jak zareaguje metal. Na filmie widoczne są instrukcje tekstowe w języku angielskim. Place an iron nail in four test tubes. Fill one with regular tap water until the nail is submerged. Fill another with regular tap water and add half a spoonful of sodium chloride – regular table salt. Shake from side to side to ensure that sodium chloride fully dissolves. Fill the third test tube with recently boiled water and add a thin layer of oil. When water is being boiled, any dissolved oxygen is removed. The layer of oil prevents more oxygen from dissolving. In the last test tube add a spoonful of calcium chloride. Calcium chloride removes any moisture. In the first tube the nail is exsposed to oxygen and moisture. In the second test tube the nail is exposed to oxygen, moisture and salt. In the third test tube the nail is exposed to water. In the fourth test tube the nail is exposed to oxygen. All four test tubes are covered with rubber bung. After a couple of days you will find that the nails in the first and second test tubes have rusted. The nail in the second test tube has rusted more than the nail in the first test tube and the rust has likely flaked off. The nails in the thrid and fourth test tubes have not rusted.

Film dostępny na portalu epodreczniki.pl

Film prezentuje instrukcję przeprowadzenia doświadczenie, w którym w czterech próbówkach umieszczono metalowe gwoździe. Do każdej z próbówek dodano inne substancje, aby sprawdzić, jak zareaguje metal. Na filmie widoczne są instrukcje tekstowe w języku angielskim. Place an iron nail in four test tubes. Fill one with regular tap water until the nail is submerged. Fill another with regular tap water and add half a spoonful of sodium chloride – regular table salt. Shake from side to side to ensure that sodium chloride fully dissolves. Fill the third test tube with recently boiled water and add a thin layer of oil. When water is being boiled, any dissolved oxygen is removed. The layer of oil prevents more oxygen from dissolving. In the last test tube add a spoonful of calcium chloride. Calcium chloride removes any moisture. In the first tube the nail is exsposed to oxygen and moisture. In the second test tube the nail is exposed to oxygen, moisture and salt. In the third test tube the nail is exposed to water. In the fourth test tube the nail is exposed to oxygen. All four test tubes are covered with rubber bung. After a couple of days you will find that the nails in the first and second test tubes have rusted. The nail in the second test tube has rusted more than the nail in the first test tube and the rust has likely flaked off. The nails in the thrid and fourth test tubes have not rusted.

CorrosioncorrosionCorrosion is a process of decaying materials caused by the action of air, water and other environmental factors. Destruction begins on the surface of the metal and progresses deeply, changing its properties. The most exposed to corrosion are seams with other metal, e.g. welding or soldering seams. Corrosion of iron and steel is called rusting. Objects made of copper, such as the roofs of historic buildings, over time are covered with a greenish coating called patinapatinapatina, which protects copper from further decaying. This process is called passivationpassivationpassivation.

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Schemat przedstawia proces korozji, corrosion. Na kawałku żelaza znajduje się kropla wody, w wyniku reakcji pomiędzy żelazem, tlenem i wodą powstała grudka rdzy. Grudkę rdzy podpisano fe dwa o trzy razy iks ha dwa o. Określono również drogę ładunku elektrycznego w procesie korozji. Mała litera e minus oznacza ładunek elektryczny - elektron. Proces anodowy to utlenianie żelaza do jonów żelaza dwa, które wędrują do roztworu. Elektron przemieszcza się do strony miejsca gdzie zachodzi proces katodowy cathodic site. Na schemacie opisano równania reakcji chemicznej związane z drogą ładunku elektrycznego. Pierwsze równanie: fe w nawiasie małe s strzałka w prawo fe dwa plus w nawiasie a ku dodać dwa małe e minus. To równanie zamieszczono przy anodic site. Po stronie cathodic site zamieszczono równanie: O dwa w nawiasie małe gie dodać cztery ha plus w nawiasie a ku dodać cztery małe e minus strzałka w prawo dwa ha dwa o w nawiasie duże l.

Passivation is therefore a process in which a certain chemical active substance in a given environment creates a protective coating on its surface – a passive layer. The coating is tight and resistant to further reactions with the environment – thus protecting the substance from decaying.

Passivation can be:

• natural, resulting from properties of the metals in particular environment;

• artificial, triggered by a deliberate reaction, e.g. the formation of a passive layer consisting of, for example, chromium oxides to protect steel alloys (a passive layer consisting of oxides, mainly chromium oxides).

The passivation phenomenon is used, for example, in the transport of concentrated nitric acid in aluminium cisterns. The aluminium reacts with the acid, forming a protective coating on the walls of the tanker by passivation. It prevents further chemical reactions and does not affect the physical and chemical properties of the acid.

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Rysunek przedstawia dwa procesy. Widoczny jest przekrój przez stalowy pręt. Na zewnętrznej powierzchni pręta znajduje się kropla wody, water oraz tlen, oxygen. W przypadku korozji, corrosion, jest to przekrój przez pręt most engineered metals. Na powierzchni metalu znajduje się zniszczenie, wgłębienie spowodowane korozję. Pojawia się rdza, rust, hydrated iron oxides oraz thickness loss. W przypadku procesu pasywacji, passivation jest to przekrój przez pręt stainless steel. Na powierzchni metalu nie znajduje się zniszczenie, jedynie kropla wody. Na powierzchni zabezpieczającej, protective layer, chromium oxide nie pojawia się rdza.

Summary

• Metals by the definition are characterized by: metallic gloss, thermal conductivity, electric conductivity, tenacity, ductility.

• Metals in a room temperature also have a constant state of matter (except mercury) and silvery‑white or silvery‑grey colour (with the exception of gold, copper).

• All metals, except noble ones (e.g. gold, silver, platinum), are subject of corrosion.

• Corrosion is the process of decomposition of materials caused by the action of air, water and other environmental factors.

• Passivation is the process of coating formation, for example on copper, which protects the metal against further destruction.

• Passivation concerns mainly metals and can be a natural process or caused intentionally by man.

Keywords

Corrosion, passivation, patina, properties of metals

Glossary