Search Results for lead corrosion

The rate and form of corrosion that occur in a particular situation depend on many complex variables. This article discusses the rate of corrosion of lead in natural and domestic water depending on the degree of water hardness caused by calcium and magnesium salts. Lead exhibits consistent durability in all types of atmospheric exposure, including industrial, rural, and marine. The article tabulates the corrosion of lead in various natural outdoor atmospheres and the corrosion of lead alloys in various soils. It explains the factors that influence in initiating or accelerating corrosion: galvanic coupling, differential aeration, alkalinity, and stray currents. The resistance of lead and lead alloys to corrosion by a wide variety of chemicals is attributed to the polarization of local anodes caused by the formation of a relatively insoluble surface film of lead corrosion products. The article also provides information on the corrosion rate of lead in chemical environments.

This article discusses the properties, primary and secondary production, product forms and applications of various grades of lead and lead-base alloys with the aid of several tables and illustrations. It lists the Unified Numbering System (UNS) designations for various pure lead grades and lead-base alloys grouped according to nominal chemical composition. The properties of lead that make it useful in a wide variety of applications are also discussed. The largest use of lead is in lead-acid storage batteries. Other applications include ammunition, cable sheathing, cast products such as type metals, terneplate, foils, and building construction materials. Lead is also used as an alloying element in steel and in copper alloys to improve machinability. The article concludes with information on the principles of lead corrosion, corrosion resistance of lead in water, atmospheres, underground ducts, soil and chemicals.

In a typical semiconductor integrated circuits (SICs) component, corrosion may be observed at the chip level and at the termination area of the lead frames that are plated with a solderable metal or alloy, such as tin and tin-lead alloys that are susceptible to corrosion. This article focuses on the key factors contributing to corrosion of electronic components, namely, chemicals (salts containing halides, sulfides, acids, and alkalis), temperature, air (polluted air), moisture, contact between dissimilar metals in a wet condition, applied potential differences, and stress. It discusses the chip corrosion and oxidation of tin and tin-lead alloys (solders) in SIC. The article also addresses the corrosion of the device terminations resulting in lead (termination) tarnishing that are caused by various factors, including galvanic corrosion, chemical residues, base metal migration and plating additives.

This article presents a detailed examination of corrosion at the various production stages of wafer fabrication. The corrosion issues related to batch metal-etch systems and single-wafer metal-etch systems are also discussed. The article provides a case study, which illustrates that the factors outside the normal processing of wafers or tool-specific problems can contribute to metal-line corrosion.

The corrosion processes of metals during burial are affected by environmental pollutants, other archaeological material, geography, microorganisms in the soil, vegetation, land use, soil chemistry, soil physical properties, and the presence or absence of water and air. This article discusses the key environmental variables that affect the corrosion of buried metal artifacts. These include water (including dissolved salts and gases), sulfate-reducing bacteria, pH (acidity), and potential (oxidizing or reducing capacity). The article contains tables that list some corrosion products identified on archaeological tin and pewter, lead, iron alloys, silver alloys, and copper alloys. It also discusses the corrosion problems after excavation and the techniques followed by archaeological department for conserving metal artifacts.

This article describes the various environmental factors that cause corrosion on metal artifacts, which include water, temperature fluctuations, pollutants, local conditions of acidity or alkalinity, vegetation, and animals. The corrosion processes experienced by five common metals, such as copper alloys, iron alloys, lead, zinc, and aluminum, used in outdoor artifacts are discussed. Finally, the article reviews conservation and preservation strategies for these five as well as gilded metals.

Batteries and fuel cells are popular forms of portable electrical energy sources. This article discusses the operation and corrosion problems inherent in batteries and fuel cells. Batteries are classified into two groups: primary or nonrechargeable batteries and secondary or rechargeable batteries. Fuel cells are classified into five types: phosphoric acid fuel cell (PAFC), solid polymer electrolyte fuel cell, alkaline electrolyte fuel cell, molten carbonate fuel cell (MCFC), and solid oxide fuel cell. The article presents reactions that occur during charging and discharging of lead-acid batteries, PAFCs, and MCFCs.

This article focuses on the internal corrosion of iron and copper in potable water. It tabulates the corrosion and water-quality problems caused by materials in contact with drinking water. The article provides a theoretical description of the reduction-oxidation reactions in water to analyze the causes of corrosion of metals in contact with water. It discusses the Langelier saturation index and the Larson index for determining corrosion in potable water systems. The article describes the two major ways of mitigation against corrosion in potable water systems. The first is to line the pipe surface physically such that water and dissolved oxygen cannot reach the metal surface and the second is to add chemical inhibitors to alter water chemistry.