Corrosion and Protection: [Weekly Topic] What is the significance of corrosion and protection of metal materials? (2011.05.30-06.06)

When metal comes into contact with its surrounding medium, the degradation caused by chemical and electrochemical reactions is called metal corrosion. From a thermodynamic perspective, with the exception of a few precious metals such as Au and Pt, all metals have a tendency to transform into ions; in other words, metal corrosion is a spontaneous and widespread phenomenon. When metal is corroded, its shape, color, and mechanical properties change, leading to equipment damage, pipeline leaks, and product contamination. This can result in serious accidents such as fires or explosions, as well as severe waste of resources and energy, causing substantial losses to the national economy. It is estimated that in developed countries around the world, the economic losses caused by metal corrosion each year account for approximately 3.5% to 4.2% of their gross national product, which is more than the total losses from various disasters such as fires, wind disasters, and others each year. Some even estimate that around 100 million tons of metal worldwide are lost due to corrosion, failure, and wear each year! Therefore, studying corrosion mechanisms and taking protective measures are of great significance for economic development. By understanding the corrosion mechanisms of metals, the causes of corrosion, and various effective anti-corrosion methods, it is possible to select materials more appropriately and implement effective anti-corrosion measures to slow down the rate of corrosion in metal materials. This is of great significance for extending the lifespan of equipment, reducing costs, and improving labor productivity. Effective methods for preventing steel corrosion can be summarized into two main categories: one is alloy-based anti-corrosion, and the other is surface coating anti-corrosion. Alloy corrosion protection methods, such as turning steel into stainless steel containing a certain amount of nickel and chromium. Surface coating anti-corrosion methods, such as metal coatings, non-metallic coatings (such as painting and plastic coating), and non-metallic films (such as chromate passivation and phosphate treatment), are widely used because of the abundant availability of raw materials, ease of manufacture, and low production costs.

Corrosion causes severe damage to modern industry; it not only results in significant direct losses but also leads to indirect losses from shutdowns and production interruptions that are difficult to estimate. It can even threaten people’s lives and property, which is why effective protective measures must be taken. Effective methods for preventing steel corrosion can be summarized into two main categories: one is alloy-based anti-corrosion, and the other is surface coating anti-corrosion. Alloy corrosion protection methods extend lifespan and reduce costs through appropriate protective measures. For some marine and ship components, if proper protection is not ensured, the equipment may become unusable within just a year. Furthermore, in other industries such as chemistry, petrochemicals, petroleum, nuclear power, and thermal energy, almost all of them must take certain protective measures into account during design. Simply put, car painting is done for aesthetic reasons and to prevent corrosion.

When metal comes into contact with its surrounding medium, the degradation caused by chemical and electrochemical reactions is called metal corrosion. From a thermodynamic perspective, with the exception of a few precious metals such as Au and Pt, all metals have a tendency to transform into ions; in other words, metal corrosion is a spontaneous and widespread phenomenon. When metal is corroded, its shape, color, and mechanical properties change, leading to equipment damage, pipeline leaks, and product contamination. This can result in serious accidents such as fires or explosions, as well as severe waste of resources and energy, causing substantial losses to the national economy. It is estimated that in developed countries around the world, the economic losses caused by metal corrosion each year account for approximately 3.5% to 4.2% of their gross national product, which is more than the total losses from various disasters such as fires, wind disasters, and others each year. Some even estimate that around 100 million tons of metal worldwide are lost due to corrosion, failure, and wear each year! Therefore, studying corrosion mechanisms and taking protective measures are of great significance for economic development

When metal comes into contact with its surrounding medium, the degradation caused by chemical and electrochemical reactions is called metal corrosion. From a thermodynamic perspective, with the exception of a few precious metals such as Au and Pt, all metals have a tendency to transform into ions; in other words, metal corrosion is a spontaneous and widespread phenomenon. When metal is corroded, its shape, color, and mechanical properties change, leading to equipment damage, pipeline leaks, and product contamination. This can result in serious accidents such as fires or explosions, as well as severe waste of resources and energy, causing substantial losses to the national economy. It is estimated that in developed countries around the world, the economic losses caused by metal corrosion each year account for approximately 3.5% to 4.2% of their gross national product, which is more than the total losses from various disasters such as fires, wind disasters, and others each year. Some even estimate that around 100 million tons of metal worldwide are lost due to corrosion, failure, and wear each year! Therefore, studying corrosion mechanisms and taking protective measures are of great significance for economic development.

Reply 1# eastchen: The corrosion of materials and their protection are of great significance. By understanding the corrosion mechanisms of metals, the causes of corrosion, and various effective anti-corrosion methods, it is possible to select materials more appropriately and implement effective anti-corrosion measures to slow down the rate of corrosion in metal materials. This is of great significance for extending the lifespan of equipment, reducing costs, and improving labor productivity.

Extending the service life of materials and reducing maintenance costs helps to cut expenses and is beneficial for environmental protection

When metal comes into contact with its surrounding medium, the degradation caused by chemical and electrochemical reactions is called metal corrosion. From a thermodynamic perspective, with the exception of a few precious metals such as Au and Pt, all metals have a tendency to transform into ions; in other words, metal corrosion is a spontaneous and widespread phenomenon. When metal is corroded, its shape, color, and mechanical properties change, leading to equipment damage, pipeline leaks, and product contamination. This can result in serious accidents such as fires or explosions, as well as severe waste of resources and energy, causing substantial losses to the national economy. It is estimated that in developed countries around the world, the economic losses caused by metal corrosion each year account for approximately 3.5% to 4.2% of their gross national product, which is more than the total losses from various disasters such as fires, wind disasters, and others each year. Some even estimate that around 100 million tons of metal worldwide are lost due to corrosion, failure, and wear each year! Therefore, studying corrosion mechanisms and taking protective measures are of great significance for economic development.

The corrosion of metals is primarily caused by chemical reactions with oxygen and water in the air, which result in the formation of compounds on the surface. Protection involves treating the metal surface, such as by applying a waterproof coating or using electrochemical methods for anti-corrosion. When metal is corroded, it affects its strength and hinders its use; the losses caused by metal corrosion each year are enormous. The damage caused by metal corrosion to the national economy is astonishing. According to a statistical report from the United States in the 1970s, worldwide, metal equipment and materials that become unusable due to corrosion each year amount to roughly one-third of the annual production of metals. As for the losses resulting from equipment damage caused by corrosion, such as shutdowns and reduced production, declining product quality, environmental pollution, harm to human health, and even serious accidents, these are even more difficult to quantify.

The significance is as follows: 1. To understand the hazards of metal material corrosion and the importance of protection against it. When metal is corroded, its shape, color, and mechanical properties change, which reduces the precision and sensitivity of machinery, equipment, instruments, and gauges. This affects their performance, may lead to their failure, and in severe cases, can even cause serious accidents. According to statistics, the metal materials lost directly due to corrosion each year account for about 10% of the annual metal production. 2. Understand the corrosion mechanisms of metal materials to enrich the theory of metal material corrosion. 3. Study methods for protecting metal materials. Common methods: (1) Perform necessary refining of the metal to reduce the amount of inert impurities in it that can conduct electricity ； (2) Conduct timely maintenance of machinery and instruments to reduce contact between metals and corrosive gases, electrolyte solutions, and humid gases ； (3) Different methods are employed depending on the application to isolate the metal from the medium that causes corrosion, such as applying grease, painting, plating, or surface passivation ； (4) Select appropriate metals or non-metals to create corrosion-resistant alloys, such as stainless steel and acid-resistant steel ； (5) Employ electrochemical protection methods, such as welding more reactive metal zinc onto the steel hull.

The corrosion of metals is primarily caused by chemical reactions with oxygen and water in the air, which result in the formation of compounds on the surface. Protection involves treating the metal surface, such as by applying a waterproof coating or using electrochemical methods for anti-corrosion. When metal is corroded, it affects its strength and hinders its use; the losses caused by metal corrosion each year are enormous. The importance of protection becomes evident then.