Luis Garfias

Wood Group Kenny · Wood Group Integrity Management

This paper demonstrates a novel methodology that can be used to determine the factors that contribute to the initiation of pitting corrosion of Corrosion Resistant Alloys (CRAs) in aggressive environments above the Critical Pitting Temperature (CPT). The work presented here shows, for the first time, simultaneous in-situ micro-visualization and ano...

The effect of the microstructure (ferrite/austenite ratio, grain size and inclusions) on the Pitting Resistance of a UNS S32550 Duplex Stainless Steels (DSS) was studied in chloride containing solutions. Increasing the ferrite content in the matrix of the UNS S32550 (by annealing the alloy at a higher temperature) resulted in a lower Critical Pitti...

The present work has as an objective to explain why a simple PREN calculation cannot be used to select Duplex Stainless Steels (DSS) for field applications. Most commercially available DSS have to be heat treated (annealed followed by oil or water quenched). A second heat treatment to release the stresses originating from machining or welding may b...

This paper presents an investigation on the corrosion performance of Ni/Au, NiP/Au, Ni/NiP/Au and Ni/NiPd/Au electrical connector coating systems. The coating systems were exposed to 10 days Class III mixed flowing gas and were subsequently examined by X-ray diffraction, focused ion beam microscopy, scanning electron microscopy and energy dispersiv...

Cover: Backscattered scanning electron microscopy cross sectional image of a Ni/NiPd/Au electronic connector after 10 days exposure to a Class III mixed flowing gas (MFG) corrosive atmosphere. This work was carried out at the Stokes Research Institute Laboratories, University of Limerick, Ireland with collaborators in Det Norske Veritas (U.S.A.), I...

The present work has as an objective to show a new technique to study in-situ the determination of precursor sites for pitting corrosion on a 25 Cr Duplex Stainless Steels (DSS) using a conventional optical microscope coupled to a potentiostat and additional hardware that allows the real time imaging on the surface of the steels above room temperat...

In-situ micro-visualization was used to study the pitting corrosion of a 25 Cr Duplex Stainless Steels in chloride containing aqueous solutions containing CO2 gas at high temperatures and high pressures. A small area on the surface of the sample was imaged and video recorded (in real time) during the anodic polarization in the gas/liquid environmen...

A Novel Mini-Autoclave where the tests are performed in-situ under an aqueous environment (simulated production brine) saturated with CO/H 2S gas mixtures was developed (with similar performance compared to a normal autoclave). The mini-autoclave ultimate limits are 400 °C and 4000 psi and can stand a mixture of a gases and liquids. The surface of...

A new methodology to study in-situ the pitting corrosion of stainless steels at high temperature and high pressure (HT/HP) was developed. This methodology allowed the real-time in-situ anodic polarization while determining the sites for pit initiation in UNS S32305 (22% Cr Duplex Stainless Steels), in chloride containing environments with additions...

Hydraulic riser tensioners for offshore drilling platforms and piston rods for hydraulic systems are used extensively in offshore oil and gas drilling and production environments. These materials are exposed to a wide variety of severe operating conditions that can range from marine atmospheres to splash zone exposures in brackish and salt water. T...

Introduction Environment and contamination Integrated circuits Printed circuit boards Hybrid integrated circuits (HICs) and multichip modules Contacts and connectors Other failures and failure mechanisms References

Introduction Lead-containing solders Lead-free solders: current alternatives Corrosion of alternative lead-free solders Lead-free solders: creep and flux residues Summary References

Accelerated corrosion testing (ACT) of external pipeline coatings traditionally includes the use of international standard tests (e.g., ASTM B117 Salt Fog Test, BS3900 Parts F4 and F12 and the ISO standard 7253). Other types of testing also include cathodic disbonding testing (CSA-Z245.20-06, ASTM G8 and/or ASTM G42) and testing the flexibility and...

Due to the increase in need for combustibles, in particular oil, sweet hydrocarbon reservoirs are fast becoming depleted. This has led to the need to tap into sour reservoirs. The presence of hydrogen sulfide (H 2S) in the reservoirs has presented new challenges to oil production companies. Among these challenges is determining the effect of H 2S o...

Accelerated Corrosion Testing (ACT) of external pipeline coatings traditionally has been associated with the ASTM(1) B117 Salt Fog Test1 (which is also similar to other standards like the BS3900 2 Parts F4 and F12 and the ISO standard 72533). There are other types of ACT for coatings that use "salt spray" type tests; for example, the acidified salt...

Environmental and Corrosion data as well as reported failures of electronic equipment in the field across different parts of the world suggests that current Accelerated Atmospheric Corrosion Tests (AACTs) do not mimic the environments typically found in developing countries. In those countries, harsher environmental conditions have shown high corro...

Highly corrosion resistance alloys (HCRAs) are becoming more popular for oilfield applications, where not only corrosion resistance is important, but also mechanical integrity and long term reliability. These materials are often exposed to a wide variety of aggressive environments that can range from marine splash zone to down-hole sour environment...

This paper describes a transmission electron microscopy (TEM) investigation of copper coupons exposed to a corrosive mixed flowing gas environment (MFG). A focused ion beam (FIB) lift-out technique was used to extract electron transparent specimens for TEM investigation. A duplex corrosion film comprising cuprite (Cu2O) and chalcocite (Cu2S) develo...

Aluminum was exposed to biodiesel with different levels of contaminants and impurities, and its corrosion behavior was evaluated by conventional electrochemical techniques. It was found that the corrosion behavior of aluminum in biodiesel contaminated with alkalis is similar to the corrosion behavior of aluminum in aqueous solutions. In addition, i...

This paper describes the results of copper coupons exposed to a class III mixed flowing gas environment (MFG) following the guidelines given by the Battelle Laboratory and the International Electrotechnical Commission for environmental testing. Corrosion products were studied in detail using scanning electron microscope, energy dispersive X-ray spe...

Precision thick chip resistors are used in a variety of different industries, from telecommunications to automotive electronics, and as such can be exposed to mild and aggressive corrosive environments. This paper investigates the corrosion performance of two generic precision thick chip resistors in a controlled corrosive atmosphere consisting of...

Thermogravimetry coupled to Fourier transform infrared spectroscopy (TGA/FTIR) has been used to study the thermal decomposition products evolved during the degradation of several commercially available organoclays (Cloisites™ Na+, 10A, 15A, 20A, 25A, 93A and 30B). It was found that the decomposition pattern of the organoclays was different for each...

Pure copper samples were exposed in an environmental chamber for 2, 4, 7, 15, and 30 days at 90% relative humidity, 40 degrees C, and 4 ppm hydrogen sulfide (H2S). Samples were subsequently subjected to microscopy and microanalysis using different techniques: scanning electron microscopy, energy analysis dispersive X-ray spectroscopy, X-ray diffrac...

Corrosion of electronic components can produce a wide range of failure signatures, from intermittent electrical faults to complete functional breakdown. This paper presents an investigation on the exposure of a simple connector-coating system. The system consists of a copper contact coated with a nickel layer underneath a gold finish layer. The sys...

A heat treatment effect on the microstructure and corrosion properties of electrodeposited Zn, Zn-Co, Zn-Fe and Zn-Ni alloy coatings was studied. Surface morphology examinations were carried with AFM, while XRD was used to determine metal lattice parameters, texture and phase composition. Low-temperature annealing (at 225C) caused the formation of...

Imaging of two adsorbed proteins on micropatterned glass substrates in air and liquid was conducted using atomic force microscopy (AFM) and near-field scanning optical microscopy (NSOM). The micropatterned glass substrates were prepared in five steps and evaluated by NSOM at each processing step. The micropatterned samples consisted of alternating...

A simple four-point probe design using thin copper wire to monitor the efficacy of a volatile corrosion inhibitor (VC) is described. Testing consisted of an aggressive atmosphere containing hydrogen sulfide (H 2S) and a relative humidity >80% to accelerate the corrosion process. The unprotected samples showed a greater voltage increase than the the...

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Thesis (Ph. D.)--University of Oxford, 1996.

The aim of the present work is to focus on the characterization of materials in situ by using a modified near‐field scanning optical microscope (NSOM) with a home‐built tuning fork head that allowed us to obtain optical imaging concurrently with topography of some systems. The first example is related to finding precursor sites for pitting corrosio...

Near-field scanning optical microscopy (NSOM) was used to obtain simultaneous topographical images of the protein surface topography in a hydrated state, and optical images of the surface with nanometer resolution. Topographical images were analyzed to measure the surface features while optical images were examined to confirm observed changes. Chan...

Steel (UNS G10400) was galvanized by using a commercial hot-dip galvanizing method. The coated steel was Immersed in a saturated calcium hydroxide (CoJOHl2) solution (pH = 12.4) and In a saturated Ca(OH)2 + 0.5 M potassium hydroxide (KOH) solution (pH = 13.4). The potential and current were measured simultaneously while the coated steel was kept im...

Photoelectrochemical microscopy (PEM) was used to locate pitting precursor sites on polycrystalline titanium immersed in sulfuric acid and in ferrocyanide solutions. PEM imaging was done with both a conventional method and a new shear‐force feedback method. The resolution of the PEM images obtained are highly dependent upon the size and preparation...

A modified near-field optical microscope (NSOM) was used to locate reactive sites on polycrystalline titanium immersed in sulfuric acid. Photoelectrochemical imaging was carried out on the NSOM by using a new shear-force feedback method. PEM with simultaneous independent topography (using the tuning fork method) resolved submicron features at react...

Evidence of metastable pitting in conventional austenitic stainless steels at room temperature is now common. Because of the small currents associated with individual events, most studies have been carried out on micro electrodes (typically 50 mm diameter). Here in contrast, with high chromium duplex stainless steels (DSS), metastable pitting is cl...

The preparation of microelectrodes for use in various electrochemical mapping techniques (e.g., scanning electro‐chemical microscopy and photoelectrochemical microscopy) is described. A commercial optical fiber (3.7 μm core diameter with and diam of cladding and coating, respectively) was stripped of its polymer coating at one end. The stripped...

Scanning electrochemical microscopy (SECM) in ferrocyanide and bromide solutions was used to locate active sites (pitting precursors) on polycrystalline Ti where oxidation of and was possible. Analysis of the electroctro‐chemically active sites was done by using electron microscopy (SEM), energy dispersive X‐ray analysis (EDX), atomic force mic...

Electrochemical studies were made of the influence of Cu on pitting behavior and active dissolution of 25% Cr duplex stainless steels (DSS) in chloride-containing neutral and acid solutions. Alloys with increased Cu content showed higher pitting potentials (E{sub p}) in 1 M hydrochloric acid (HCl) and 3.5% sodium chloride (NaCl) solutions. In HCl,...

The effect of annealing temperature on pitting resistance of 25% Cr duplex UNS S32550 was investigated. CPT and pitting potential were determined for this alloy after annealing at 1020, 1060, 1100 and 1140 degrees C. The higher values of CPT and pitting potential were found after annealing at the lower temperatures. Fitting was always observed pref...

Synthesis of ceramic YBa2Cu3O7-d by solid-state reaction was performed under different conditions. Different values of cooling rate and oxygen flow were used, and no significant influence on superconducting characteristics of the samples was observed. A major influence on their mechanical properties was found.

The present work describes the corrosion studies (using electrochemical techniques) of coated and uncoated steels exposed to corrosive mixtures (including 6% ferric Chloride, alcohols, particles and water). Open Circuit Potential (OCP), Cyclic Potentiodynamic Polarization (CPP) and a modified version of the Zero Resistance Amperometry (ZRA) testing...

Hydraulic riser tensioners (for offshore drilling platforms) and piston rods (for hydraulic systems) have been extensively used in marine environments. They are exposed to a wide variety of severe operating conditions that range from marine atmospheres to splash zone in brackish and saltwater. The present work describes a novel testing methodology,...