22. Unit 10

I. Match English words with their Russian equivalents:

1. Self-repairing давать

2. Enhance выщелачивать

3. Corrosion inhibitor растворимый

4. Exposure вздуваться

5. Soluble замедлитель коррозии

6. Leach out улучшать

7. Blister основа

8. Delamination с автоматическим устранением неисправностей

9. Matrix расслоение

10. Destruction подвергать какому-либо воздействию

11. Dope разрушение

II. Fill in the gaps using the given words:

1. Found, damaged, based, developed, affecting, divided

New generation of self-repairing coatings are (_____) to further enhance anticorrosive properties of metal substrates. In conventional systems, the barrier property of the coating is the main mechanism for metal protection against corrosion. However, the barrier performance of a coating will be (____) soon and corrosive electrolyte comes into contact with the metal substrate. Use of corrosion inhibitors is another approach to produce active coatings in exposure to corrosive electrolytes. These active agents are soluble in corrosive electrolytes and protect metal surface by passivation mechanism. There are different kinds of corrosion inhibitors which can be (____) to three main types (___) on the mechanism controlling corrosion process. Anodic inhibitor (only reduces anodic reaction rate), cathodic inhibitor (only reduces cathodic reaction rate) and mixed inhibitors (both cathodic and anodic reactions can be influenced). The solubility of the inhibitors is (____) an important factor (____) its corrosion inhibiting efficiency.

2. Designed, adding, leached, coating, designed, using, loaded

Very low solubility leads to low passivating behavior at metal substrate. There are disadvantages for very high solubility: first, the inhibitor will be rapidly (___) out from the (___) and second, the active surface blistering and delamination may occur due to osmotic pressure effect. As a result of osmotic pressure, water transportation into the coating matrix and passive layer destruction may occur. Because of this, (____) active inhibitors at high concentration is not possible in conventional processes. This problem has been (___) in modern coatings (____) nanoscale container (carrying active agents like inhibitors). In this approach, active inhibitor is (___) into nanocontainer. The nanocontainers have a permeable shell which could release active agents in coating matrix. In fact, the shell is (____) in a way which release active agent in a controlled process.

C) Encapsulated, distributed, doped, seen, loaded, keeping, resulting, using, trapped, depending

There is another approach which instead of nanocontainer in which the passive layer is (____) with active agents. However, interaction of active materials with coating matrix leads to short-coming in the stability and self-repairing activity of the coating. The disadvantages cannot be (____) for the system (____) with nanocontainers as the coating matrix does not directly contact with active agents. The nanocontainers will be uniformly (____) in coating matrix (____) active materials in a (____) state. The nanocontainers respond to any signal or when the environment undergoes changes they release (____) active materials. Controlling nanocapsuls permeability and nanocontainers compatibility with coating matrix are the most important parameters affecting their anticorrosion performance. The optimum nanocontainers size range is 300-400 nm. (____) nanocontainers with larger sizes may lead to large hollow cavities formation inside coating matrix (____) in significant reduction of the passive protective properties of the coating. (____) on the sensitive components presented in nanocontainers (i.e polyelectrolytes or metal nanoparticles) different parameters like ionic strength, pH changes, temperature, ultrasonic treatment, magnetic field alteration may influence shell permeability.

3. Answer the following questions:

1. Why are the new generation of self-repairing coatings developed?

2. What is the main mechanism for metal protection against corrosion?

3. How many types of corrosion inhibitors do you know?

4. Why is the solubility of the inhibitors an important factor?

5. What are the results of low and high solubility?

6. How can you explain what nanocontainer is and what its functions are?

3. Find English equivalents in the text:

Пустота, снижение, проницаемость, покрытие, тонкая пленка, основа, электролит, недостаток, корпус, поверхность, замедлитель коррозии.

3. Correspond the given words to the gaps

Corrosion inhibitor, permeable shell, metal substrate, osmotic pressure, magnetic field, trapped state, hollow cavity.

1. As a result of …., water transportation into the coating matrix and passive layer destruction may occur.

2. The nanocontainers have a ….

3. ….. alteration may influence shell permeability.

4. Using nanocontainers with larger sizes may lead to large … formation inside coating matrix.

5. There are different kinds of …..

6. Corrosive electrolyte comes into contact with the …..

7. Coating matrix keeps active materials in a ….

3. Put the words in the correct order to make up sentences.

1. Are, distributed, matrix, the, coating, in, nanocontainers

2. Rapidly, out, the, is, inhibitor, leached.

3. Any, the, respond, to, nanocontainers, signal.

4. Into, the, water, matrix, transports, coating.

5. Optimum, size, the, range, is, nanocontainers, 300-400 nm.