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At least 19 recordsLinked to original sources
PubMed1995

Fretting corrosion accelerates crevice corrosion of modular hip tapers.

The use of multiple-component systems in orthopedic surgery gives the surgeon increased flexibility in choosing the optimal implant, but introduces the possibility of interfacial corrosion. Such corrosion could limit the longevity of prostheses due either to tissue reactions to corrosion products, or to device failure. The incidence and nature of corrosion of modular total hips was evaluated in a consecutive series of 79 retrieved implants from University Hospitals of Cleveland. Surfaces were examined with stereo- and scanning electron microscopy. Several laboratory studies were undertaken to examine mechanisms that might contribute to the initiation of corrosion. The first set of experiments investigated the effect of head neck extension; the second study looked at the effect of material combinations on fretting corrosion and crevice corrosion. Analysis of retrieved implants demonstrated that fretting corrosion played a major role in the initiation of interface corrosion, and that a correlation existed between corrosion and length of neck extensions. Laboratory studies showed that longer head neck extensions may be more susceptible to fretting corrosion because of an instability at the interface. Short-term mixed-metal corrosion studies demonstrated that the coupling of cobalt and titanium alloys did not render the interface more susceptible to corrosion. It is hypothesized that fretting corrosion contributes to the initiation of modular interface corrosion, and that the problem can be reduced by design changes that increase the stability of the interface.

Alloys↗
PubMed2005

Simulation of corrosion product activity for nonlinearly rising corrosion on inner surfaces of primary coolant pipes of a typical PWR under flow rate transients.

For nonlinear accelerating corrosion, calculation of activated corrosion products on inner surfaces of primary coolant pipes have been done in a typical pressurized water reactor (PWR) under flow rate perturbations. Computer program CPAIR-P (Corrosion Product Activity In Reactors) (Deeba et al., 1999) has been modified to accommodate for time-dependent corrosion rates. Results, for (24)Na, (56)Mn, (59)Fe, (58)Co, (60)Co and (99)Mo, show that the specific activity in primary loop approaches equilibrium value under normal operating conditions fairly rapidly. Predominant corrosion product activity during operation is due to (56)Mn, and cobalt isotopes dominate the activity after shutdown of reactor. Flow rate perturbations and different types of rising corrosion rates were introduced in the system and effects on saturation activity were studied. For a linear decrease in flow rate and a constant corrosion rate, the total coolant activity and activity on pipe scale approaches higher saturation values when compared to normal condition values. With a nonlinearly accelerating corrosion, the behavior of specific activity changes considerably. The flow rate perturbations on specific activity for pipe scale results in a new saturation value which depends on both the changes in flow rate (Delta w) and equilibrium corrosion rate (C(s)) values. However, the time taken to reach the saturation activity depends on the slope of corrosion rate. For a slow pump coastdown, the activity does not show an initial drop when flow rate starts decreasing. It monotonically rises and follows the slope of corrosion rate. The peak value and decay of activity after scram are strong functions of flow rate and removal efficiencies.

Journal Article↗
PubMed2003

Corrosion and wear-corrosion behavior of NiTi modified by plasma source ion implantation.

The understanding of corrosion behavior in NiTi is critical for the devices using this shape-memory alloy. In order to improve the surface properties of NiTi such as corrosion resistance, plasma source ion implantation (PSII) technique was employed with oxygen as incident ions at three levels of implantation dose (5x10(16), 1x10(17) and 3x10(17) ions/cm(-2)). Pitting corrosion and wear-corrosion behavior of control and PSII-modified Ti-50.7at% Ni alloy were evaluated by cyclic potentiodynamic polarization and wear-corrosion measurements. Surface characterization was used to interpret the different corrosion behavior observed between control and oxygen-implanted samples. Results showed that corrosion behavior was influenced by both heat treatment and surface modification. The best pitting corrosion resistance was observed for samples with Af=21 degrees C modified by oxygen implantation at a dose of 1x10(17) ions/cm(-2). Better wear-corrosion resistance was observed for oxygen-implanted samples.

Biocompatible Materials↗
PubMed1989

[Corrosion of Ag-Pd-Cu alloys in saline solution. Amount of released elements and electrochemical corrosion].

The effect of the Pd content on corrosion and tarnish resistance in twelve experimental alloys was investigated. The alloys were prepared with a composition of Pd content from 20.1 to 30.1 at %. The composition of the alloys Ag-20% Pd, Ag-25% Pd and Ag-30% Pd was varied by adding Cu 5 wt%, 10 wt% and 15 wt% to each of them. The corrosion resistance was estimated by the amount of the released Ag, Cu and by electrochemical corrosion behavior in 0.86% NaCl solution at 37 degrees C. The tarnish resistance was assessed using a spectrophotometer. The test solutions included 0.86% NaCl solution, 0.1% Na2S solution and a mixture of 1.0% lactic acid and 0.1% Na2S, all at 37 degrees C, in sealed containers. The results are summarized as follows. The larger the amount of Pd in Ag-Pd binary alloys and Ag-Pd-Cu ternary alloys, the more stable was the release and the release rate of Ag, Cu and corrosion resistance increased in 0.86% NaCl solution. The addition of Cu to Ag-Pd binary alloys increased the release and release rate of Ag, but there was a shift of the rest potential in the noble direction. A relationship was found between the amount of Ag and Cu released from Ag-Pd-Cu ternary alloys. In this study, an increase in corrosion resistance was observed when the content of Pd in Ag-Pd binary alloys was 25 wt%. Furthermore, it was also observed that Ag-Pd-Cu ternary alloys need an additional 30 wt% Pd for corrosion resistance. Moreover, the addition of Cu must be kept lower than 10 wt%. The tarnish resistance of the twelve experimental alloys was good in 0.86% NaCl solution but was barely improved with increased in the Pd content in sulfide solution. The correlation between electrochemical corrosion behavior and tarnish resistance was not significant, but the correlation between the amount of Ag, Cu release from Ag-Pd-Cu ternary alloys and tarnish resistance was remarkable.

Copper↗
PubMed1991

Corrosion properties of soldered joints. Part II: Corrosion pattern of dental solder and dental nickel-chromium alloy.

Six nickel-chromium (Ni-Cr) alloys joined with two solders were evaluated for degree of corrosion after they were immersed in corrosive solution for 100 days. The corroded surface of the Ni-Cr alloy and the cross section of the soldered joint were observed and the solution of nickel and copper (Cu) ions in each combination was measured. No corrosion was observed in the high-resistant Ni-Cr alloys with high Cr content. Pitting corrosion was seen on low-resistant Ni-Cr alloys, which had less Cr content. In the cross section of the joint, the joint of silver solder became porous by corrosion and the corrosion advanced especially along the interface. Solution of Ni ions was detected in all of the combinations of Ni-Cr alloys and solders with exception of the combination of high-resistant Ni-Cr alloys and gold solder. On the other hand, solution of Cu ions was detected in all of the combinations with silver solder.

Chromium↗
PubMedDate not supplied

In vivo corrosion of 316L stainless-steel hip implants: morphology and elemental compositions of corrosion products.

Eleven surgically retrieved stainless steel implants showing varying degrees of surface corrosion were examined to characterize the morphology and composition of corrosion products. The implants were fabricated to the specification AISI316L (Muller) and BS 3531 pt 1 1971-78 (Charnley). They had been in place for 9-21 y (Mean :13 y) and failures were due to aseptic loosening. The morphology and chemical compositions of corrosion products were recorded using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). Nine implants had areas of corrosion covering 1-5 cm of the stem, partially or all round. Corrosion existed in layers. The layers consisted either of chromium in association with sulfur, or iron in association with phosphorus. Variable amounts of calcium and chlorine were also present in all layers. Nickel, which makes up 13% of the alloy, was persistently absent. The presence and extent of corrosion was independent of the alloy composition and could not be related to the duration of implantation.

Aged↗
PubMed1988

Effect of Phosphate on the Corrosion of Carbon Steel and on the Composition of Corrosion Products in Two-Stage Continuous Cultures of Desulfovibrio desulfuricans.

A field isolate of Desulfovibrio desulfuricans was grown in defined medium in a two-stage continuous culture apparatus with different concentrations of phosphate in the feed medium. The first state (V1) was operated as a conventional chemostat (D = 0.045 h) that was limited in energy source (lactate) or phosphate. The second stage (V2) received effluent from V1 but no additional nutrients, and contained a healthy population of transiently starved or resting cells. An increase in the concentration of phosphate in the medium fed to V1 resulted in increased corrosion rates of carbon steel in both V1 and V2. Despite the more rapid corrosion observed in growing cultures relative to that in resting cultures, corrosion products that were isolated under strictly anaerobic conditions from the two culture modes had similar bulk compositions which varied with the phosphate content of the medium. Crystalline mackinawite (Fe(9)S(8)), vivianite [Fe(3)(PO(4))(2) . 8H(2)O], and goethite [FeO(OH)] were detected in amounts which varied with the culture conditions. Chemical analyses indicated that the S in the corrosion product was almost exclusively in the form of sulfides, while the P was present both as phosphate and as unidentified components, possibly reduced P species. Some differential localization of S and P was observed in intact corrosion products. Cells from lactate-limited, but not from phosphate-limited, cultures contained intracellular granules that were enriched in P and Fe. The results are discussed in terms of several proposed mechanisms of microbiologically influenced corrosion.

Journal Article↗
PubMed1989

Ranking corrosion efficiency: a Latin square study on rat lung microvascular corrosion casts.

Scanning electron microscopy of corrosion casts is an important tool for the study of microvascular structure but few systematic studies on methods of specimen preparation have been reported. This study sought to determine the relative importance of factors involved in corrosion. It compared potassium hydroxide, sodium hydroxide and water as major corrosive agents. It tested the size of the tissue sample, and the use of prealkali autolysis, detergent, and proteolytic enzymes in a Latin square designed study. The main findings were that sodium and potassium hydroxide were better than water (P less than 0.0001) and the longer the corrosion time the better corroded the samples were (P less than 0.0001). Although not a controlled factor, higher room temperature was also associated with better corrosion. The use of proteolytic enzymes, detergent, and warm tap water alone before the alkali treatment did not significantly improve the corrosion in this study, although this does not preclude an effect with another experimental design.

Animals↗
PubMed1997

Fretting corrosion resistance and fretting corrosion product cytocompatibility of ferritic stainless steel.

To avoid nickel ion release from SUS317L as an implant material, a new type of nickel, commercially free, of high purity, and high chromium ferritic stainless steel, was developed. The new stainless steel (FJ) was studied for aspects of fretting corrosion and cytocompatibility compared with SUS317L. A pin-on-plate fretting corrosion test in an artificial physiologic solution, and cell culture in media with the addition of the artificial physiologic solution used for fretting was conducted. Resistance to the fretting induced crevice corrosion of FJ was higher than that of SUS317L because of the favorable electrochemical stability of the FJ alloy. The amount of iron ion or colloidal fine particles released from FJ was about a quarter of that from SUS317L, although the weight loss of a pin of FJ was almost 5/3 that of SUS317L. The artificial physiologic solution used for SUS317L fretting was more harmful to the growth of L929 and MC3T3-E1 cells than that used for FJ fretting. FJ was therefore superior to SUS317L as a biomaterial, judging from the resistance to fretting-induced crevice corrosion, electrochemical stability, and the cytocompatibility of fretting corrosion products.

3T3 Cells↗
PubMed1996

Effect of vapor phase corrosion inhibitor on microbial corrosion of aluminum alloys.

Vapor phase corrosion inhibitors were used to investigate the antimicrobial activities and anticorrosion of aluminum alloy. Aspergillus flavus, A. niger, A. versicolor, Chaetomium globosum and Penicillium funiculosum had moderate to abundant growth on the aluminum alloy AA 1100 at Aw 0.901, while there was less growth at Aw 0.842. High humidity stimulated microbial growth and induced microbial corrosion. Dicyclohexylammonium carbonate had a high inhibitory effect on the growth of test fungi and the microbial corrosion of aluminum alloy, dicyclohexylammonium caprate and dicyclohexylammonium stearate were the next. Aluminum alloy coating with vapor phase corrosion inhibitor could prevent microbial growth and retard microbial corrosion.

Alloys↗
PubMed2004

Prediction of corrosion rates of water distribution pipelines according to aggressive corrosive water in Korea.

The drinking water network serving Korea has been used for almost 100 years. Therefore, pipelines have suffered various degrees of deterioration due to aggressive environments. The pipe breaks were caused by in-external corrosion, water hammer, surface loading, etc. In this paper, we focused on describing corrosion status in water distribution pipes in Korea and reviewing some methods to predict corrosion rates. Results indicate that corrosive water of lakes was more aggressive than river water and the winter was more aggressive compared to other seasons. The roughness growth rates of Dongbok lake showed 0.23 mm/year. The high variation of corrosion rates is controlled by the aging pipes and smaller diameter. Also the phenolphthalein test on a cementitious core of cement mortar lined ductile cast iron pipe indicated the pipes over 15 years old had lost 50-100% of their lime active cross sectional area.

Corrosion↗
PubMed2003

Cell density related H2 consumption in relation to anoxic Fe(0) corrosion and precipitation of corrosion products by Shewanella oneidensis MR-1.

In the absence of oxygen, a protective H2 film is formed around an Fe(0) surface, inhibiting the electron flow from this surface. Our study of anoxic corrosion of Fe(0) beads revealed that, in the presence of Shewanella oneidensis MR-1, H2 removal and precipitation of Fe mineral particles on the cell surface are determining processes for corrosion. These two biologically mediated processes were governed by cell density. H2 removal by Shewanella oneidensis was detected at cell concentrations of 1.0 x 10(6) live cells ml-1 and higher and H2 was electron donor for denitrification of NO3-. The removal of the protective H2 layer from Fe(0) beads by Shewanella oneidensis, resulted in an increase of Fe release out of the Fe(0) beads from 153 +/- 25 mg l(-1) to 196 +/- 7 mg l-1 after 20 h. When the cell concentration exceeded 1.0 x 10(8) live cells ml-1, precipitation of iron minerals on the cell surface was characteristic for the greatest percentage of MR-1 cells, whereas micrometre-scale iron precipitates not associated with culturable cell biomass significantly decreased in number. Addition of supernatant of a corrosion assay with high cell concentration induced metabolic activity in a corrosion assay with low cell concentration, resulting in increased H2 consumption and Fe release from Fe(0) beads. Homoserine lactone-like molecules were detected in the supernatant by a bio-assay, suggesting the involvement of a quorum-sensing regulatory mechanism.

4-Butyrolactone↗