Preface

The book covers some important topics regarding stainless steel corrosion in different corrosive media.

Corrosion, while silent and often subtle, is probably the most significant cause of the degradation of society's structures. Enhancing the life of structures and engineered materials while protecting the environment and public safety is one of the paramount technological challenges for our nation and the world. Corrosion-related problems span a wide spectrum of materials and systems that impact our daily lives. Corrosion seriously affects many sectors of nations' economies. Billions of dollars per year are lost due to corrosion. The cost of corrosion can be reduced to 20% to 25% of this annual figure by applying corrosion control technologies. These include material selection, proper designing, electrochemical protection coating, and inhibitors. Among these methods, inhibitors are used for a wide range of applications in oil industries, pipelines, refineries, domestic central heating systems, industrial cooling systems, pickling of metals, and acidization of oil wells.

Corrosion contributes to losses of 7.5 billion USD in world revenue every year, which is estimated to be 3.4% of the world's total GDP. However, in India, economic loss due to corrosion is 1670 billion USD, which is around 4.2% of GDP. The biggest problem in the industry is corrosion, and various steps have been taken to resolve this problem. In the petroleum industry, stainless steel alloys are commonly used in production, refinery, turbine parts, fasteners, and so on due to their resistance to corrosion as well as high mechanical strength.

Stainless steels consist of chromium, which is resistant to corrosion and heat. The oxide layer appearing on the surface of stainless steel in contact with air and water represents a barrier that protects the steel against undesirable and destructive reactions in surrounding environments. Generally, the corrosion resistance of stainless steel depends on the stability of the oxide film grown on its surface. However, the oxide film or passive film can be altered by severe working conditions like high acidity, high temperature, and the presence of impurities in industrial acids. To overcome this problem, the use of mitigators, coatings, and other protection methods is an effective tool against corrosion. In addition, the use of inhibitors for commonly used stainless steel spares the industry the economic burden of using materials with high levels of alloying elements that are too expensive. Furthermore, as guidelines for the use of inhibitors become more stringent and exigent on the ecological aspect, the development of biodegradable and environmentally compatible or ecofriendly inhibitors is becoming an important issue. The use of polymers, nanocomposites, biopolymers, plant extracts, and many more methods are employed to overcome the corrosion of stainless steel.

I would like to thank all the authors and reviewers for their invaluable contributions.

**Dr. Ambrish Singh** School of New Energy and Materials, Southwest Petroleum University, Chengdu, China

Section 1 Introduction
