Electrochemical migration of Sn and Sn solder alloys: a review

Sn and Sn solder alloys in microelectronics are the most susceptible to suffer from electrochemical migration (ECM) which significantly compromises the reliability of electronics. This topic has attracted more and more attention from researchers since the miniaturization of electronics and the explosive increase in their usage have largely increased the risk of ECM. This article first presents an introductory overview of the ECM basic processes including electrolyte layer formation, dissolution of metal, ion transport and deposition of metal ions. Then, the article provides the major development in the field of ECM of Sn and Sn solder alloys in recent decades, including the recent advances and discoveries, current debates and significant gaps. The reactions at the anode and cathode, the mechanisms of precipitates formation and dendrites growth are summarized. The influencing factors including alloy elements (Pb, Ag, Cu, Zn, etc.), contaminants (chlorides, sulfates, flux residues, etc.) and electric field (bias voltage and spacing) on the ECM of Sn and Sn alloys are highlighted. In addition, the possible strategies such as alloy elements, inhibitor and pulsed or AC voltage for the inhibition of the ECM of Sn and Sn solder alloys have also been reviewed

Research on the Intelligent Safety Monitoring System of Pipeline Corrosion in Acidic Oil and Gas Fields—II

AbstractAll kinds of corrosion monitoring techniques have their own advantages and obvious disadvantages when applied in acidic oil and gas fields. According to the characteristics of various technologies, an intelligent safety monitoring system was established based on electrochemical noise probe with galvanic corrosion probe, electrochemical hydrogen permeation probe and electric resistance probe. This paper presents the development of monitoring unit, system integration, and field test and data analysis. The results demonstrate that electrochemical noise not only determines the occurrence of corrosion, but also shows the characteristic of localized corrosion clearly; electrochemical hydrogen permeation technique reveals several advantages in the monitoring progress including simplicity, high sensitivity and high reliability, while the improved electric resistance probe shows a better environmental suitability. The accuracy and reliability of corrosion monitoring has been greatly increased by this integrated technique which can achieve the consistency and complementation of much information

New insight into the fitness of 13Cr stainless steel in H2S-containing environment at high temperature

In the oil and gas industry, the selection of tubing and casing materials is required to follow international standard ISO 15156. However, it does not provide guidance on selecting stainless steel materials for H2S-containing wells above 232 °C, which raises uncertainty about the suitability of 13Cr steel. This work focuses on investigating the mechanical degradation and failure mechanisms of 13Cr stainless steel exposed to high-temperature conditions and proposed a creep constitutive model. Then, the corrosion and cracking mechanisms of 13Cr stainless steel at temperatures ranging from 150 °C to 350 °C were elucidated. Results show that 13Cr stainless steel meets the current material selection criteria (GB/T34907-2017) for mechanical properties and creep resistance. In the range of 150–250 °C, the localized corrosion is dominant, and stress-oriented hydrogen-induced cracking occurs at 150 °C. As the temperature increases from 250 °C to 350 °C, although the maximum value of uniform corrosion rate is as high as 0.2960 mm/a, the cracking does not happen. Therefore, with the implementation of suitable protective measures, 13Cr stainless steel can be utilized in wells that the temperatures ranging from 250 °C to 350 °C and H2S partial pressures up to 0.17 MPa. This aligns with the global carbon-neutral agenda

Limiting Current Density of Oxygen Reduction under Ultrathin Electrolyte Layers: From the Micrometer Range to Monolayers

The oxygen reduction reaction (ORR) under ultrathin electrolyte layers is a key reaction in many processes, from atmospheric corrosion to energy conversion in fuel cells. However, the ORR current under ultrathin electrolyte layers is difficult to measure using conventional electrochemical methods. Hence, reliable data are scarce for the micrometer range and totally missing for the sub-micrometer range of the electrolyte layer thickness. Here, we report a novel hydrogen-permeation-based approach to measure the ORR current underneath thin and ultrathin electrolyte layers. By using a Kelvin-probe-based measurement of the potential, which results from dynamic equilibrium of oxygen reduction and hydrogen oxidation, and the corresponding hydrogen charging current density, the full currentpotential relationship can be constructed. The results shed a new light on the nature of the limiting current density of ORR underneath ultrathin layers of electrolyt

Corrosion Behaviors of Q345R Steel at the Initial Stage in an Oxygen-Containing Aqueous Environment: Experiment and Modeling

The ingress of oxygen into pressure vessels used in oil & gas production and transportation could easily result in serious corrosion. In this work, the corrosion behaviors of Q345R steel at the initial stage in 1 wt.% NaCl solution were investigated using electrochemical techniques. The effects of oxygen concentration, temperature and pH on corrosion behaviors were discussed. Simultaneously, a numerical model based on the mixed potential theory was proposed. The results show that the proposed model accords well with the experimental data in the pH range from 9.0 to 5.0. In this pH range, the oxygen reduction reaction, H+ reduction, water reduction, and iron oxidation can be quantitatively analyzed using this model. However, this model shows a disagreement with the experimental data at lower pH. This can be attributed to the fact that actual area of reaction on the electrode is much smaller than the preset area due to the block effect resulted from hydrogen bubbles adsorbed on the electrode surface