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At least 19 recordsLinked to original sources
PubMed1976

Studies of the corrosion susceptibility of metallic cement restrictors: comparative corrosion behavior of stainless steel and cobalt-chromium alloys.

Passive film and accelerated corrosion tests were performed on both wrought AISI 316L stainless steel and wrought Vitallium (Haynes Stellite 25) Charnley Type cement restrictors. The morphology and incidence of corrosion at the wire-wire crevices and the methacrylate-metal crevices were determined by scanning electron microscopy. The results are interpreted in view of the previously-documented crevice corrosion susceptibility of these two alloys.

Bone Cements↗
PubMed1992

Microbial corrosion of stainless steel.

Stainless steel, developed because of their greater resistance to corrosion in different aggressive environments, have proved to be affected, however, by various processes and types of corrosion. Some of these types of corrosion, mainly pitting, is activated and developed in the presence of microorganisms, which acting in an isolated or symbiotic way, according to their adaptation to the environment, create a favorable situation for the corrosion of these steel. The microorganisms that are involved, mainly bacteria of both the aerobic and anaerobic type, modify the environment where the stainless steel is found, creating crevices, differential aeration zones or a more aggressive environment with the presence of metabolites. In these circumstances, a local break of the passive and passivating layer is produced, which is proper to these types of steel and impedes the repassivation that is more favorable to corrosion. In the study and research of these types of microbiologically influenced corrosion are found electrochemical techniques, since corrosion is fundamentally an electrochemical process, and microbiological techniques for the identification, culture, and evaluation of the microorganisms involved in the process, as well as in the laboratory or field study of microorganism-metal pairs. Microstructural characterization studies of stainless steel have also been considered important, since it is known that the microstructure of steel can substantially modify their behavior when faced with corrosion. As for surface analysis studies, it is known that corrosion is a process that is generated on and progresses from the surface. The ways of dealing with microbiologically influenced corrosion must necessarily include biocides, which are not always usable or successful, the design of industrial equipment or components that do not favor the adherence of microorganisms, using microstructures in steel less sensitive to corrosion, or protecting the materials.

Alloys↗
PubMed2026

DURABLE: A Workflow for Determining Corrosion-Driving and Protective Microbial Mechanisms.

Microbiologically influenced corrosion (MIC) threatens global infrastructure, causing billions of dollars in annual losses. Its persistence stems from unresolved mechanisms─particularly the metabolites produced by microorganisms that drive or inhibit corrosion─and the microbial community structures. Progress has been hindered by the absence of systematic workflows to rapidly and accurately identify MIC-relevant microorganisms and their functions. Here, we present DURABLE (Detection of Unique Corrosion Resistant or Accelerating Biologics in a Laboratory Environment), a pipeline that couples high-throughput microbial screening with genomic and metabolic workflows. We applied the DURABLE workflow to six diesel tank samples and revealed fuel-dependent microbial community structures, which showed greater diversity and evenness in bacterial communities than their fungal counterparts. The workflow used carbon steel beads to rapidly screen over 80 bacterial isolates for corrosive activity, reducing assay time to approximately 2 days compared with the conventional 30-day metal coupon test. More than 40 isolates were identified as corrosive. Further testing using mass spectrometry analysis revealed corrosion-associated metabolites, which were further validated using electrochemical assays. Thus, DURABLE achieved a ∼15-fold increase in screening speed and provided a scalable and mechanistic framework for dissecting MIC dynamics. We expect this advance will enable the development of precision mitigation strategies in hydrocarbon fuel infrastructure.

Bacteria↗
PubMed1978

Corrosion behavior of cast and forged cobalt-based alloys for double-alloy joint endoprostheses.

An ideal combination of mechanical and corrosion properties of long-term implants such as joint endoprostheses has yet to be found. Besides being resistant to pitting and crevice attack, which can lead to corrosion fatigue and stress corrosion cracking failures, the implant material must be highly resistant to wear and abrasion. Two cobalt-based alloys, wrought CoNiMoTi and air-cast CoCrMo, were subjected to a number of selected in vitro electrochemically and chemically accelerated corrosion tests in chloride-containing solutions with wrought AISI-316L used as a reference alloy. A limited number of immersion tests in FeCl3 and acidified FeCl3 solutions were also conducted. It is found that the mechanical properties of wrought CoNiCrMoTi alloy qualify it as a substitute for cast CoCrMo alloy and wrought AISI-316L in anchorage shaft production for all types of joint endoprostheses. Wrought CoNiCrMoTi has a higher resistance to fatigue cracking compared with cast CoCrMo and is as resistant to selective corrosion phenomena such as stress corrosion cracking.

Alloys↗
PubMed1979

In vitro corrosion of Ti-6Al-4V and type 316L stainless steel when galvanically coupled with carbon.

In vitro corrosion experiments were conducted employing potentiostatic polarization techniques, a saline environment and candidate biomaterial alloy/carbon combinations. Corrosion currents and potentials of carbon/metal couples were predicted by mixed-potential theory utilizing the polarization curves generated. The alloys examined were annealed ELI grade Ti-6A1-4V and cold-worked 316L stainless steel while the types of carbon examined were LTI pyrolytic carbon and vapor-deposited carbon. It was determined that galvanic couples of carbon to cold-worked 316L stainless steel with carbon/metal area ratios of 10:1 to 100:1 produced coupled corrosion potentials in the range of the observed breakdown potential of the stainless steel. It was therefore predicted that localized corrosion in the form of pitting could occur on the cold-worked stainless steel when coupled to carbon with area ratios of 10:1 or greater. The titanium alloy did not exhibit a breakdown potential up to a potential of 1.2 V. Therefore, accelerated corrosion was not predicted for the titanium alloy to carbon galvanic couples under these experimental conditions. Direct carbon/alloy coupling experiments were conducted to verify the corrosion currents and potentials predicted from mixed-potential theory and polarization curve analysis. The experimental and theoretical values showed good agreement.

Alloys↗
PubMed1979

'Rusters'. The corrosive action of palmar sweat: II. Physical and chemical factors in palmar hyperhidrosis.

When measuring sweating rates, close correspondence was found with the clinical estimation of hyperhidrosis. Corrosion was seen to increase with increasing sweat rates, reaching its maximum after an assumed rise in the actual sodium chloride concentration on the skin surface due to evaporation of water. The findings confirm that hyperhidrosis is of primary importance in the constitution of a 'ruster', and are also in good agreement with experimental reports. The small variations in palmar skin pH had no influence on the degree of corrosion; nor had the character of the metal surface. Of the two types of metal studied. corrosion was much more severe on the type having the lowest concentration of copper, thus confirming that increasing copper concentrations have a positive effect in reducing corrosion rates. At 50--60% relative humidity (RH) corrosion increased as time elapsed, whereas at 40% RH no corrosion developed on a sweat-contaminated plate. When exposed to 75% RH, metal samples became severely corroded in the course of a few days. Protective methods for the avoidance of rust are mentioned, with special emphasis on frequent handwashing.

Adolescent↗
PubMed1978

Corrosion of copper in utero.

The influence of corrosion on the copper wire in the Copper T-200 intrauterine device (IUD) was studied in devices which had been in utero for 3 to 52 months. This was done mainly by examining cross-sections of the wires under a light microscope. Corrosion was normally localized to narrow areas and led to breakage and fragmentation of the copper wire. Neither deposits on the wire nor corrosion products prevented the dissolution of the copper. The progress of the corrosion over a given time was determined by comparing the depth of corrosion with the original dimension of the wire. The lifetime of the IUD was evaluated on the basis of the progress of corrosion, the calculated copper release, and the number of cases of wire breakage. It was found that the Copper T-200 could be left in place for up to 45 months.

Chemical Phenomena↗
PubMed1979

The problem of corrosion and tarnish of dental restorative and implant metals.

The linear polarization technique has been used to measure polarization resistances and corrosion currents directly in the mouths of baboons and in vitro for a wide range of dental and implant alloys. Good correlations were found to exist between these two conditions, indicating that this test is accurate and valid as well as being simple to perform. Intraoral corrosion proceeded faster, probably due to abrasion by foodstuffs. Tarnish has also been measured using an intraoral tristimulus colorimeter and results were compared with the corrosion determinations. The tarnish of pure metals (Au, Ag, and Cu) was inversely proportional to corrosion. Gold alloys tarnished little but varied in corrosion current. Dental amalgams corroded the most but the tarnish experience depended more on their chemistry than their precious metal composition.

Animals↗
PubMed1978

[Dental amalgam corrosion].

Corrosion of amalgam is a natural phenomenon of the behaviour of a metallic substance in the oral environment. Corrosion is a process in which we have a anodic reaction resulting in a loss of electrons and a cathodic reaction resulting in a captation of electrons. One single amalgam restoration in a electrolitic environment as the saliva shows areas acting as anode and others acting as cathode. Certain factors may influence the corrosion: they are the composition of the alloy, the particle size and form, the mercury content, the presence of more or less important quantity of gamma-2 phase, the degree of surface finishing, etc. It is likely that the dispersion phase alloy are more resistant to corrosion than the conventional alloys and that fluoridates amalgams are also more prone to corrosion.

Corrosion↗
PubMed1992

In vitro corrosion fatigue of 316L cold worked stainless steel.

The corrosion resistance of 316L cold worked stainless steel depends upon its thin protective oxide layer; and if this is partially broken down, corrosion resistance depends upon its tendency for repassivation. Since the intended function of stainless-steel implants is to sustain musculoskeletal forces, research toward the stability of the oxide film during dynamic loading in simulated bodylike fluids is warranted. A pilot corrosion fatigue study was, therefore, performed on uniaxial tension fatigue specimens cycled to various maximum stress levels near their yield point while immersed in 37 degrees C isotonic saline solution, and combined with the electrochemical insult of (a) imparting an 800 mV vs. SCE anodic potential for 20 s to stimulate local film breakdown, and then (b) returning to a constant 200 mV vs. SCE anodic potential and maintaining that potential during cyclic loading until the specimens broke in two. During the anodic polarization by continuously monitoring the current it was possible to (a) observe the repassivation and corrosion behavior following stimulation, and (b) detect crack initiation, crack propagation and failure onset. The combined effects of accelerated corrosion and mechanical fatiguing disturbed the repassivation tendency and reduced the crack initiation times and the fatigue lives as compared to air and saline controls. As the maximum cyclic load levels were increased, the fatigue lives were further foreshortened.

Cold Temperature↗
PubMed1978

Diagnosis of acute corrosive lesions of the oesophagus.

Early diagnosis of acute corrosive lesions of the oesophagus enables adequate treatment to be given to the patient and prevents unnecessary treatment of uninjured individuals. In an analysis of 64 patients of varying ages subjected to oesophagoscopy during a 10-year period for suspected corrosive lesions of the oesophagus caused by alkali, acids and other corrosive substances, it was found that neither clinical signs, laboratory investigations nor X-ray examination gives sufficient information about whether the patient has a corrosive lesion of the oesophagus or not. Oesophagoscopy establishes the diagnosis. Patients suspected of having corrosive lesions of the oesphagus should therefore be subjected to oesophagoscopy as soon as their condition permits.

Acute Disease↗
PubMed1978

Corrosion behavior of structural phases in high copper dental amalgam.

The effects of crevice corrosion on the major structural phases of a high copper dental amalgam were studied in vitro. Three kinds of samples were used: (1) amalgam prepared from a high copper, single composition alloy, (2) annealed ingots of the Ag3Sn and Cu3Sn phases, and (3) high copper, single composition alloy tablets electroplated with mercury. Specimens were examined in a scanning electron microscope before and after the exposure to a corrosion environment. The Ag3Sn and Cu3Sn phases were least affected by corrosion. The Ag-Hg-Sn phase (gamma1) slowly deteriorated, but the attack was nonuniform. The Cu6Sn5 phase exhibited good corrosion resistance, better than that of gamma1 phase. Particles of a tin rich phase of uncertain origin were observed on some of the samples after long exposures.

Copper↗
PubMed1992

Corrosion testing by potentiodynamic polarization in various electrolytes.

The effect of different electrolytes on the results from potentiodynamic polarization corrosion testing was studied for nine different dental alloys. In general, the difference in the results was greater between certain alloys using the same electrolyte than between the electrolytes with the same alloy. However, there were some differences between the electrolytes, most pronounced when testing dental amalgams. The electrolyte consisting of 1% NaCl seemed to offer the most corrosive environment. Darvell's and Fusayama's solutions were much less corrosive, at least for dental amalgam specimens. With regard to the ranking by corrosion sensitivity of the amalgams, only the results obtained by using Fusayama's solution were consistent with the clinical experience of the materials.

Analysis of Variance↗
PubMed2026

Cost-effectiveness analysis of omeprazole for preventing esophageal stricture in patients with Zargar grade 2b and 3a corrosive esophageal injuries: A trial-based economic evaluation.

BACKGROUND: Corrosive esophageal injury frequently results in esophageal stricture requiring repeated endoscopic dilatation and substantial healthcare expenditure. This study evaluated the cost-effectiveness of omeprazole plus standard treatment compared with standard treatment alone for preventing esophageal stricture in adult patients with Zargar grade 2b and 3a corrosive esophageal injuries. METHODS: A trial-based economic evaluation was conducted alongside a randomized controlled trial from the healthcare provider and patient perspectives. Twenty patients were randomized to receive either standard treatment alone (n = 10) or standard treatment plus omeprazole (n = 10). Direct medical costs were analyzed using the incremental cost-effectiveness ratio. Deterministic one-way sensitivity analysis and probabilistic sensitivity analysis using Monte Carlo simulation were performed. RESULTS: The incidence of corrosive esophageal stricture was 20% (2/10) in the omeprazole group and 70% (7/10) in the standard treatment group (relative risk, 0.29; 95% confidence interval, 0.08-1.05; Fisher's exact test, P = .070). Omeprazole plus standard treatment reduced healthcare costs by THB 4642.30 per patient from the provider perspective and THB 5476.60 per patient from the patient perspective. The intervention remained the dominant strategy across all deterministic sensitivity analyses. Probabilistic sensitivity analysis demonstrated that 68.3% and 78.8% of simulations favored omeprazole from the provider and patient perspectives, respectively. CONCLUSION: Omeprazole plus standard treatment may represent a cost-effective strategy for adult patients with Zargar grade 2b and 3a corrosive esophageal injuries. However, these findings should be considered preliminary and require confirmation in larger multicenter randomized controlled trials.

Humans↗
PubMed1975

In vitro chloride corrosion behaviour of Dispersalloy.

The in vitro chloride corrosion behaviour of Dispersalloy has been investigated by anodic polarization as a function of time after trituration (ageing) and compared with conventional dental amalgam. Dispersalloy is a commercial alloy containing a mechanical mixture of Ag-3-Sn and Ag-Cu eutectic in the ratio 2:1. From measurement of 1 h corrosion potentials it was observed that over a time period of 1 year Dispersalloy became appreciably more noble (potential shift from minus 500 mV to minus 350 mV Vs. SCE), whereas the corrosion potential of conventional amalgam remains unchanged. Initial anodic polarization profiles for Dispersalloy indicated presence of gamma2 and Cu-6-Sn-5 phases as evidenced by presence of the minus 250 mV peak. However, the current density associated with this peak was about three times less than that of conventional amalgam. As a function of ageing time the polarization profile is shifted in the direction of decreasing current density and after 1 year the minus 250 mV peak is absent. The anodic polarization profile of conventional amalgam is unchanges after 1 year. The improved corrosion resistance of Dispersalloy is attributed to the formation of Cu-3-Sn as a function of time due to solid state reaction between Ag-Cu eutectic and gamma2.

Chlorides↗