Michael Schorr Wiener

Effect of H2S on corrosion in polluted waters: a review

Abstract The present article provides an overview of the effect of hydrogen sulphide (H2S) on corrosion in polluted waters, including sea, river, brackish, geothermal and sewage waters. H2S is a weak, reducing acid which originates from sulphide minerals by natural acidification and/or from sulphur – bearing, decaying organic matter by bacterial action. Human and industrial activities increase the generation of corrosive gases, dissolved in water: CO2, H2S and NH3. Carbon steel, stainless steel, aluminium alloys and copper base alloys are corroded by H2S, producing metallic, non-stable sulphide films. The H2S content in various waters, the electrode potential pH (Pourbaix) diagrams for Fe and Cu in H2S containing systems, and the electrochemical and corrosion performance of steel in oxygen depleted, H2S polluted waters, which indicate active corrosion behaviour, are presented and discussed.

Copper Corrosion by Atmospheric Pollutants in the Electronics Industry

Hydrogen sulphide (H2S) is considered one of the most corrosive atmospheric pollutants. It is a weak, diprotic, reducing acid, readily soluble in water and dispersed into the air by winds when emitted from natural, industrial, and anthropogenic sources. It is a pollutant with a high level of toxicity impairing human health and the environment quality. It attacks copper forming thin films of metallic sulphides or dendrite whiskers, which are cathodic to the metal substrate, enhancing corrosion. H2S is actively involved in microbially influenced corrosion (MIC) which develops in water, involving sulphur based bacteria, in oxidizing and reducing chemical reactions. H2S is found in concentrated geothermal brines, in the atmosphere of geothermal fields, and in municipal sewage systems. Other active atmospheric pollutants include SOX, NOX, and CO. This investigation reports on the effects of H2S on copper in microelectronic components of equipment and devices, with the formation of nonconductive films that lead to electrical failures.

Micro and Nano Corrosion in Steel Cans Used in the Seafood Industry

The use of metal containers for food preservation comes from the early nineteenth century, has been important in the food industry. This type of packaging was developed to improve food preservation, which were stored in glass jars, manufactured for the French army at the time of Napoleon Bonaparte (XVIII century), but were very fragile and difficult to handle in battlefields, so it was decided the produce metal containers (Brody et al, 2008). Peter Durand invented the metallic cans in1810 to improve the packaging of food. In 1903 the English company Cob Preserving, made studies to develop coatings and prevent internal and external corrosion of the cans and maintain the nutritional properties of food (Brody, 2001). Currently, the cans are made from steel sheets treated with electrolytic processes for depositing tin. In addition, a variety of plastic coatings used to protect steel from corrosion and produce the adequate brightness for printing legends on the outside of the metallic cans (Doyle, 2006). This type of metal containers does not affect the taste and smell of the product; the insulator between the food and the steel, is non-toxic and avoid the deterioration of the food. The differences between metal and glass containers, as well as the negative effects that cause damage to the environment and human health are presented in Table 1. The wide use of steel packaging in the food industry, from their initial experimental process, has been very supportive to keep food in good conditions, with advantages over other materials such as glass, ceramics, iron and tin. The mechanical and physicochemical properties of steel help in its use for quick and easy manufacturing process (Brown, 2003). At present, exist a wide variety of foods conserved in steel cans, but in harsh environments, they corrode. Aluminum is used due to its better resistance to corrosion, but is more expensive. With metal packaging, the food reaches to the most remote places of the planet, and its stays for longer times without losing its nutritional properties, established and regulated for health standards by the Mexican Official Standards (NOM). The difference between using metal cans to glass (Table 1) indicate greater advantages for steel cans (Finkenzeller, 2003). In coastal areas, where some food companies operate, using steel cans, three types of deterioration are detected: atmospheric corrosion, filiform corrosion and microbiological corrosion. Even with the implementation of techniques and methods of

Corrosion in the Food Industry and Its Control

From ancient times human beings have survived on a diet consisting on a relatively few species of plants and animals, domesticated and then cultivated and grown. Three cereals, wheat, rice and corn, supply the need of human energy, protein and vitamins requirements for the network of metabolic processes to maintain normal body function and temperature. In a prehistoric era, indigenous peoples all over the world were moving in inhospitable grounds obtaining their daily sustenance by hunting and gathering fruits, seeds and roots. Actually, the three largest markets worldwide, according to their production extent, the number of consumers and their economic and social significance are the food, energy and water markets. Furthermore, their increasing scarcity and soaring prices lead to a global critical situation. The demand for increased food supply is related both, to population increase and personal and family income. Consequently, the food market is the largest one, including all the inhabitants of this planet, about seven billion, since everyone eats! The organized food production and supply starts with the agricultural revolution, developed and implemented in the fertile valleys of the rivers Tigris-Euphrates in Mesopotamia and the Nile in ancient Egypt. Afterwards the food industry expanded, avoided widespread famine and ensured that sufficient food is supplied for all people to stay healthy. Current food research had been largely stimulated by rapidly growing world demand but technological advances in food processing, equipment and production plants have also contributed. A most significant aspect in the search of new nutritional food is the requirement for adequate protein in regions where meat and fish are not available. Additionally, advances in the food industry (FI) such as preservation, packaging and storage facilitate food delivery and minimized health hazards. Space flight conditions have stimulated the creation of space food which meets highly demanding standards for conservation and to be ready for easy digestion e.g. solid dehydrated food easily converted into liquid or paste food. Techniques for preserving food from natural deterioration following harvest or slaughter dated to prehistoric times applying drying, salting, fermentation of milk and fruits and pickling of vegetables. Modern techniques include canning, freezing, dehydration, cooking under vacuum and addition of chemicals. The principal causes of food spoilage are growth

The Discrete Wavelet Transform and Its Application for Noise Removal in Localized Corrosion Measurements

The present work discusses the problem of induced external electrical noise as well as its removal from the electrical potential obtained from Scanning Vibrating Electrode Technique (SVET) in the pitting corrosion process of aluminum alloy A96061 in 3.5% NaCl. An accessible and efficient solution of this problem is presented with the use of virtual instrumentation (VI), embedded systems, and the discrete wavelet transform (DWT). The DWT is a computational algorithm for digital processing that allows obtaining electrical noise with Signal to Noise Ratio (SNR) superior to those obtained with Lock-In Amplifier equipment. The results show that DWT and the threshold method are efficient and powerful alternatives to carry out electrical measurements of potential signals from localized corrosion processes measured by SVET.

Use of Steel in Food Packaging

Humankind developed through millennia the food industry that includes technologies for food conservation. Steel packaging has a long history, providing safe containers for all types of food and a great variety of beverages. Tinplate steel was selected due to its high strength, malleability, and formability. The cans are protected against corrosion. Many important researches have been done to maintain the food quality and the consumers health. Acid corrosion in food cans and can filiform corrosion are described and their mechanism reported. Steel-can recycling has several potential benefits for the global economy and the environmental quality.

Microcorrosión en sensores ópticos usados para detectar microorganismos en industrias de alimentos de Tijuana, México

El uso de micro dispositivos electronicos como sensores opticos en las operaciones de deteccion de microorganismos (MO), es de gran importancia por las faciles y rapidas respuestas para detectar y enviar las senales electricas a indicadores que pueden ser luminosos o de conexion a computadoras, principalmente. Los procesos de deteccion de los MO, son aplicados en las actividades de envasado de alimentos en plantas industriales de este tipo, con el objetivo de eliminar al maximo todos los microorganismos que puedan generar corrosion microbiologica (CMB). Estos dispositivos operan a velocidades de microsegundos cuando estan en buenas condiciones, detectando los MO rapidamente en toda la superficie interna de las latas metalicas usadas para el envasado de alimentos. Los micro sensores opticos (MSO) se ubican en los equipos electronicos en interiores de una planta industrial dedicada a la manufactura y comercializacion de alimentos. Estos MSO estuvieron expuestos a variaciones de clima principalmente en los meses de marzo y octubre, siendo las epocas del ano donde se presentan los vientos Santa Ana (VSA). Dichos VSA modificaron las condiciones climaticas en el interior de la empresa, del ano 2010 al 2011 cuando se realizo la investigacion. Esto contribuyo a cambios en los rangos de humedad relativa (HR) desde 30% hasta 80% y de temperatura de 1 °C a 2 °C en periodos diarios en lugares sin flujo de viento principalmente donde se realizaban los procesos de manufactura de alimentos. Aunado a las variaciones de los factores climaticos, se observaron procesos de corrosion uniforme y por picaduras por la presencia de contaminantes del aire como cloruros principalmente y sulfuros como segundos agentes contaminantes con un efecto que contribuia al deterior de los MSO. Los MSO operaron en condiciones en mal estado o dejaron de operar, sin realizar el proceso de deteccion adecuado y se genero CMB que deterioro los alimentos y origino perdidas economicas.

Relationship of corrosion with global warming and climate change

Global climate change is one of the most important concerns for world governments and is a major research subject for the scientiÞ c international community with the participation of multi and interdisciplinary groups. This special issue aims to outline the adverse effects of climate change on the corrosion and deterioration of infrastructure assets. Two fundamental reports; the United Nations Intergovernmental Panel on Climate Change (IPCC) and the N. Stern, The Economics of Climate Change, 2007, Cambridge University Press, UK, outline parameters that will effect infrastructure, temperature change, atmospheric moisture change, sea level raise, wind, desertiÞ cation, pollution and inclusive biological infestation.

Techniques for corrosion monitoring, edited by Lietai Yang

This is a multiauthored compendium; its value lies in the inclusion of the authors ́ wide spectrum of knowledge, expertise, experience and approaches, from many fi elds of corrosion science, technology and engineering. Why are modern CM techniques are so important? They provide early warning of costly corrosion damage and critical information on where the damaging event is occurring and about the rate of deterioration. This information encourages greater understanding; it is essential to take decisions about the type, urgency and cost of preventive and curative measures to be applied on site, without delay. An array of useful, diverse CM techniques such as electrochemical, physical, chemical, electrical, non-destructive is presented, as are techniques for particular environments: microbial, soil, under coatings, concrete, under cathodic protection, engine exhaust, cooling water, pulp and paper industry, chemical plants and pipelines. In cases of materials and structures failures, these techniques – as is well described – will assist in the correct selection of longer-life materials durable, protective coatings and corrosion control procedures. In this crucial time of global warning, energy crisis and economic turmoil, effective CM will extend the life of the infrastructure, with the potential of saving a large fortune in materials, equipment and structures. This book is a valuable resource for implementing suitable actions to achieve these ambitious goals! Evidence of the scientifi c, but at the same time practical, approach to CM is the abundant application of instrumental techniques, reported and illustrated, e.g. scanning electron Techniques for corrosion monitoring, edited by Lietai Yang