Michael Schorr

Corrosion and scaling at Cerro Prieto geothermal field

Purpose – The aim of this work is to study the corrosion and scaling factors, mechanisms and processes affecting the materials, equipment and installations of the Cerro Prieto geothermal field (GTF).Design/methodology/approach – The physicochemical characteristics of the geothermal well and fluids were analysed, recorded and related to the corrosion and scaling phenomena.Findings – The high temperature and salinity of the steam‐brine mixture and the presence of hydrogen sulphide and carbon dioxide impart a severe level of corrosivity.Originality/value – Corrosion and scaling control assure an efficient production regime, provide for the durability of the GTF engineering materials and equipment and contribute to environmental quality.

Application of Vapour Phase Corrosion Inhibitors for Silver Corrosion Control in the Electronics Industry

The indoor corrosion of silver components used in the manufacture of electronic devices represents a hard challenge for the electronic industry in Mexico. In this work, a case of silver corrosion occurring in a TV manufacturing plant was documented, analysed and diagnosed. The main pollutant present in the indoor environment of the factory was hydrogen sulphide, which causes rapid silver tarnishing due to the formation of silver sulphide corrosion products. Silver corrosion rates were evaluated by gravimetric assays and surface SEM and EDX analyses were performed to characterize the corrosion film. In order to control the corrosion process VAPPRO vapour phase corrosion inhibitors were used.

Corrosion Control in the Desalination Industry

Desalination is a viable solution to the 21th century´s shortage of freshwater. The most widely used desalination processes are thermal and membrane. Other modern techniques apply solar and electrical energy for evaporation and electrodialysis. Many desalination plants (DP) are located in desertic/arid regions with a harsh climate and limited rainfall. About one-fifth of the DPs operate in the Middle East, with Saudi Arabia producing half of the world desalted water. The final selection of materials of construction for plant equipment must be a compromise between technological and economic factors. Corrosion problems and their solutions in several DPs in the Middle East, USA and Mexico are presented.

The phosphoric acid industry: equipment, materials, and corrosion

Abstract Phosphoric acid (PA) is an important industrial chemical used as an intermediate in the fertilizer industry, for metal surface treatment in the metallurgical industry, and as an additive in the food industry. Wet-process PA (WPA) is produced by the attack of sulfuric acid (H2SO4) on phosphate rock (PR). Other wet processes use HCl and posterior solvent extraction technology. The corrosivity of phosphate ores, during the production of WPA, depends on two main factors: the chloride content and the interaction between HF formed in the WPA reaction slurry with SiO2, Al2O3, and MgO present in the ore. Many forms of corrosion, mainly localized, are encountered in the PA production plants and facilities such as erosion-corrosion (EC), selective corrosion, pitting, stress-corrosion cracking, intergranular corrosion, and corrosion at high temperature. Laboratory and plant corrosion tests were performed to recognize the corrosion types; EC measuring instruments were developed, built, and applied. The PA industry is spread out worldwide in Europe, Asia, Africa and America, including countries that operate PR mines and produces PA, phosphatic fertilizers, and phosphate-based products. Cases of corrosion in PA industrial equipment and plants are presented and discussed, based on the authors’ experience and knowledge.

Spectroscopy Analysis of Corrosion in the Electronic Industry Influenced by Santa Ana Winds in Marine Environments of Mexico

Climate change in some regions of the world is due to the effect of variations meteorological phenomenon, such as El Nino southern Oscillation (ENOS), which occasioning rainfalls in winter and even flooding, cold fronts and tropical cyclones in Baja California. Santa Ana winds (SAW) are influenced by ENOS, originated in the Santa Ana Canyon in the Mojave desert (Travina et al, 2002), which cause rapidly changes in the climate conditions in the south west of California, USA y northwest of Baja California, Mexico. SAW are developed when the desert is cold, and are presented most commonly during autumn and spring seasons. This originates fast temperature rises and relative humidity (RH) drops, causing damage in the vegetation of these zones and changes in the meteorological conditions affecting the environments in indoor of industrial plants. Due to drastic changes in temperature and humidity in indoors of companies by SAW, an effect of strong transitions of these climatic factors occur which in combination with air pollutants as sulphurs and chlorides generate deterioration of copper metals of electronic machines and equipments. Analysis of raw materials used in electronic devices and electrical failures of electronic components were carried out in 15 companies in the coast of Baja California, Mexico. This study presents an analysis of winter of 2009, early spring of 2010 and late autumn of 2010. Humidity and temperature ranges of these winds can change rapidly from dry to wet, cold to warm and reverted in some hours. These several variations influence the corrosion rate of copper electrical connectors and connections of electronic equipments near the coast, installed in industrial parks of the northwest of Mexico in marine environments. In this region are located two important cities: Tijuana in the border with San Diego, California where was evaluated this phenomenon in ten companies and in Ensenada at 100 km. near the USA-Mexico border, with five industrial plants analyzed. The amount of defective devices increased in 25% and failures in electronic machines and equipments in 28% in the period of SAW occurred, compared with other seasons. In addition, 100% of raw materials located in warehouses of industrial companies, 33% were unusable. Auger electron spectroscopy (AES) technique was applied to determine the corrosion products in electrical connections and connectors of industrial electronic devices, equipments and machines.

Corrosion Inhibition of the Galvanic Couple Copper-Carbon Steel in Reverse Osmosis Water

The purpose of this paper is to evaluate the electrochemical behaviour of corrosion inhibition of the copper-carbon steel galvanic couple (Cu-CS), exposed to reverse osmosis water (RO) used for rinsing of heat exchangers for heavy duty machinery, during manufacture. Molybdate and nitrite salts were utilized to evaluate the inhibition behaviour under galvanic couple conditions. Cu-CS couple was used as working electrodes to measure open circuit potential (OCP), potentiodynamic polarization (PP), and electrochemical impedance spectroscopy (EIS). The surface conditions were characterized by scanning electron microscopy (SEM) and electron dispersive X-ray spectroscopy (EDS). The most effective concentration ratio between molybdate and nitrite corrosion inhibitors was determined. The morphological study indicated molybdate deposition on the anodic sites of the galvanic couple. The design of molybdate-based corrosion inhibitor developed in the present work should be applied to control galvanic corrosion of the Cu-CS couple during cleaning in the manufacture of heat exchangers.

Effect of H2S on Corrosion in Polluted Waters

There is a deep universal concern today about the influence of pollutants on the environment including soil, air and in particular water, and about their effects on the durability of engineering materials and the deterioration of structures and the infrastructure. Water pollutants affect the terrestrial, atmospheric and aquatic environments, and even when present at very low levels of a few ppm may impair human health, aquatic life and water quality. The avoidance of water pollution is, therefore, an important part of water resource management. The present work provides an overview of the effects of hydrogen sulfide (H2S) on corrosion in polluted waters, including sea, river, brackish, geothermal and sewage waters.

The natural gas industry: Equipment, materials, and corrosion

Abstract Corrosion is a crucial worldwide problem that strongly affects the oil and gas industry. Natural gas (NG) is a source of energy used in industrial, residential, commercial, and electric applications. The abundance of NG in many countries augurs a profitable situation for the vast energy industry. NG is considered friendlier to the environment and has lesser greenhouse gas emissions compared with other fossil fuels. In the last years, shale gas is increasingly exploited in the USA and in Europe, using a hydraulic fracturing (fracking) technique for releasing gas from the bedrock by injection of saline water, acidic chemicals, and sand to the wells. Various critical sectors of the NG industry infrastructure suffer from several types of corrosion: steel casings of production wells and their drilling equipment, gas-conveying pipelines including pumps and valves, plants for regasification of liquefied NG, and municipal networks of NG distribution to the consumers. Practical technologies that minimize or prevent corrosion include selection of corrosion-resistant engineering materials, cathodic protection, use of corrosion inhibitors, and application of external and internal paints, coatings, and linings. Typical cases of corrosion management in the NG industry are presented based on the authors’ experience and knowledge.

Electrochemical Study of Corrosion Behavior Of Rare Earth Based Chemical Conversion Coating on Aerospace Aluminum Alloy

The anticorrosion properties of cerium and praseodymium based chemical conversion coatings deposited on AA6061-T6 were evaluated in NaCl 0.01 M aqueous solution at room temperature using Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic Polarization (PDP). Coatings microstructure and morphology were observed by Scanning Electron Microscopy (SEM). Coatings compositions were characterized by Energy Dispersive X-Ray Spectroscopy (EDX). The obtained results showed that: 1) Cerium sulphate based coatings possess superior resistance to localized corrosion in comparison to the praseodymium nitrate based ones; 2) One minute of immersion shows good anticorrosive properties of the Ce2(SO4)3 based coatings; 3) Post-deposition phosphate treatment notably improves the anticorrosive behavior and 4) Hydrogen peroxide addition to the cerium based formulation accelerates the coating formation.

Kinetics and Structure Aspects of the Dissolution of Metals in Acids

The dissolution of metals in acids is a heterogeneous electrochemical reaction, taking place at the interface between a solid and a liquid, described in terms of energy and configuration of the species involved. The energy of activation for two stainless steels in phosphoric acid was determined from their corrosion rates in the temperature range 50-120 o C, applying the Arrhenius equation. Energy of activation values for the overall process of anodic metal dissolution and cathodic hydrogen release are in the 10-20 Kcal mol -1 range. Metal corrosion is a structure sensitive process; its mechanism and rate are related to the density of surface defects, based on the Boltzman expression. A model for the activated complex is proposed based on considerations of energy and configuration. This work is an integration of a theoretical analysis and an experimental investigation of metal corrosion in acids.