Chromium Deposition Research Articles

Peculiarities of chromium electrodeposition from water − dimethylformamide solutions

Electrodeposition of chromium from both CrCl2- and CrCl3-containing dimethylformamide (DMF)–water solutions is studied. It is found that the process of chromium deposition from Cr(II)-containing solutions is stable during the whole period of electrolysis, while the rate of electrodeposition from Cr(III)-containing electrolytes gradually decreases. To explain the experimental results, it has been assumed that the film consisting of chromium oxide and hydroxide species is formed in the near-cathode region during electrolysis in Cr(III)-based baths. The physical properties of this film are critical for chromium electrodeposition. It is necessary to maintain the negative potential sufficient for Cr(II)→Cr electroreduction at the electrode-film interface for the sustained chromium plating. Under such conditions, thick (up to 100 μm) Cr–C coatings of good quality can be deposited.

Wear Behaviour of Electroless heat Treated Ni-P Coatings as Alternative to Electroplated hard Chromium Deposits

In this present study was evaluated the influence of heat treatment on the wear resistance of electroless high phosphorus nickel coating (9-10% P wt.). In addition, both untreated and treated Ni-P deposits were then compared to electroplated hard chromium coatings in terms of wear behaviour. Three different heat treatment conditions were performed at temperatures of 320oC, 400oC and 500oC under different holding times. The selection of the heat treatment conditions was chosen considering the results obtained by a differential scanning calorimetry (DSC) analysis. The wear behaviour of the Ni-P samples was investigated through a non-lubricated ball on plate test carried out against an Al2O3 counter-face. After an analysis of the friction coefficient, microstructure of the worn surface, width and chemical composition of the wear track, was possible to conclude that the heat treatment affect positively the wear resistance of Ni-P coatings. Treatment conditions of 320oC with 9 hours holding time and 400oC with 1 hour holding time showed the best results due to a structural change from amorphous supersatured solid solution of phosphorus in nickel to a crystalline structure of nickel crystallites and nickel phosphides (Ni3P) occurred between 320oC and 360oC that was verified after x-ray diffraction analysis. Moreover, Ni-P heat treated coatings showed better results when compared to electroplated hard chromium deposits, hence acting as a natural alternative for chromed coatings.

Sr Surface Segregation on La0.6Sr0.4Co0.2Fe0.8O3-δ Porous Solid Oxide Fuel Cell Cathodes

In recent years, mixed ionic-electronic conducting (MIEC) materials such as La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) have been studied and developed as solid oxide fuel cell (SOFC) cathodes, due to their high activity for the oxygen reduction reaction at temperatures below 800°C.1 However, a number of such MIEC materials that contain Sr, including LSCF, exhibit Sr surface segregation at elevated temperatures. In prior work done mainly on dense thin-film MIEC electrodes, Sr-rich surface phases (e.g., SrO) have been shown to hinder the oxygen surface exchange process.2-5 A recent study, where the surface Sr coverage was quantified by a chemical etching method combined with 3-dimensional (3D) tomography, demonstrated increased amount of surface segregated Sr, along with increased polarization resistance, on LSCF porous electrodes after ageing at 800°C for 800 h.6 In this work, we present a study of degradation mechanisms of porous LSCF electrodes under thermal ageing. LSCF symmetric electrode cells with Gd0.1Ce0.9O1.95 (GDC) electrolytes were maintained in ambient air at various temperatures ranging from 550°C to 850°C for different periods of time up to 1500 h, without current/polarization. Electrochemical impedance spectroscopy (EIS) measurements were taken once per day at 700°C, for cells aged at 700°C and 850°C. Increases in the polarization resistance with time by as much as 2 times were found for both ageing temperatures. The electrode morphological changes and Sr surface segregation were examined utilizing a combination of 3D tomography via focused ion beam-scanning electron microscopy (FIB-SEM) and chemical etching with inductively coupled plasma-optical emission spectrometry (ICP-OES) detection. The 3D imaging showed that the LSCF electrodes did not coarsen measurably over 700 h at 700°C or 1500 h at 850°C. On the other hand, the ICP-OES analysis detected an increased amount of water-soluble Sr with increasing ageing temperature and time, as shown in Fig. 1. Application of Adler-Lane-Steele (ALS) model using the measured impedance and microstructural parameters suggested that the increased polarization resistance resulted from a substantial decrease in both the surface exchange kchem and oxygen diffusion coefficients D* . The LSCF electrodes aged below 650°C showed no significant increase in surface Sr content compared to the as-prepared sample, indicating there may be a kinetic limitation on Sr surface segregation at lower temperatures. 1. Gao, Z., Mogni, L. V., Miller, E. C., Railsback, J. G. & Barnett, S. A. A perspective on low-temperature solid oxide fuel cells. Energ Environ Sci 9, 1602-1644 (2016). 2. Pan, Z. H., Liu, Q. L., Zhang, L., Zhang, X. W. & Chan, S. H. Effect of Sr Surface Segregation of La0.6Sr0.4Co0.2Fe0.8O3-delta Electrode on Its Electrochemical Performance in SOC. J Electrochem Soc 162, F1316-F1323 (2015). 3. Zhao, L., Drennan, J., Kong, C., Amarasinghe, S. & Jiang, S. P. Insight into surface segregation and chromium deposition on La0.6Sr0.4Co0.2Fe0.8O3-delta cathodes of solid oxide fuel cells. J Mater Chem A 2, 11114-11123 (2014). 4. Liu, Y. H. et al. Performance stability and degradation mechanism of La0.6Sr0.4Co0.2Fe0.8O3-delta cathodes under solid oxide fuel cells operation conditions. Int J Hydrogen Energ 39, 15868-15876 (2014). 5. Simner, S. P., Anderson, M. D., Engelhard, M. H. & Stevenson, J. W. Degradation mechanisms of La-Sr-Co-Fe-O3SOFC cathodes. Electrochem Solid St 9, A478-A481 (2006). 6. Wang, H. Q. et al. Mechanisms of Performance Degradation of (La,Sr)(Co,Fe)O3-delta Solid Oxide Fuel Cell Cathodes. J Electrochem Soc 163, F581-F585 (2016). Figure 1

Chromium Poisoning of Cathodes in Solid Oxide Fuel Cells and its Mitigation Employing CuMn1.8O4 Spinel Coatings on Interconnects

Intermediate temperature solid oxide fuel cells (IT-SOFCs) enable the use of chromia-forming alloys in interconnects and balance-of-plant (BoP) materials. However, depending on the SOFC operating conditions, the chromium (Cr) containing species can transport and deposit in the SOFC cathodes and deteriorate their performances. In order to investigate the Cr-poisoning phenomena, anode-supported planar SOFCs with Sr-doped LaMnO3 (LSM) + yttria-stabilized zirconia (YSZ) cathode active layer and LSM cathode current collector layer were fabricated and electrochemically tested in contact with Crofer interconnect at 800 °C. The cathode atmosphere (dry air or 10% humidified air) and current condition (no current or constant cathodic current) were varied in tests on identical cells, and the performance degradations under different test conditions were compared. It was found that both humidity and cathodic current can promote Cr poisoning. Microstructure characterizations also confirmed major amounts of Cr-containing deposits at the cathode/electrolyte interfaces of the cell tested with cathodic current and/or humidity. Free energy minimization calculations and thermogravimetric experiments were performed to determine the chromium vapor species that form over the chromia-forming alloy interconnect and result in the chromium deposition. Based on these results, the roles of humidity and cathodic current in chromium poisoning are evaluated, and a performance degradation mechanism associated to chromium vapor species dissociation at the cathode/electrolyte interface is proposed. In order to mitigate the effect of Cr-poisoning, a protective Cu-Mn spinel coating was applied on the interconnect surface. The Cu-Mn spinel coating has good thermal compatibility, high stability and electronic conductivity at the SOFC operating temperature. The candidate interconnect material (Crofer22H meshes) with no protective coating, those with commercial CuMn2O4 spinel coating and the ones with lab-developed CuMn1.8O4spinel coating were investigated. The lab-developed CuMn1.8O4spinel coating was deposited on the Crofer22H mesh by electrophoretic deposition and densified by a reduction and re-oxidation process. Anode-supported SOFCs with LSM based cathode with different Crofer22H meshes (bare, commercially coated CuMn2O4, and lab-coated CuMn1.8O4) were electrochemically tested at 800 °C with a constant cathodic current (0.5 A/cm2) for total durations of up to 216 hours, and the cell performances were characterized by current-voltage measurements every 24 hours. Cross sections of the Crofer22H meshes and the SOFC cathodes were examined before and after the cell tests by scanning electron spectroscopy and energy dispersive X-ray spectroscopy. The results of the mitigating effects of the two types of Cu-Mn spinel interconnect coatings on Cr-poisoning of the SOFC cathodes were compared. It was observed that the performance of the denser lab-developed Cu-Mn spinel coating was distinctly better showing significantly less chromium containing deposits at the cathode/electrolyte interface after the test.

Roles of humidity and cathodic current in chromium poisoning of Sr-doped LaMnO3-based cathodes in solid oxide fuel cells

Performance degradation of cathodes caused by chromium deposition and poisoning is one of the major challenges to overcome for long-term operation of solid oxide fuel cells (SOFCs). To fundamentally understand the mechanisms of the degradation phenomenon, it is necessary to investigate the roles of humidity and cathodic current in chromium poisoning.In this study, anode-supported SOFCs, with Sr-doped LaMnO3 (LSM) based cathode are employed. These cells are electrochemically tested at 800 °C with and without chromia-forming interconnect. On identical cells, different cathode atmospheres (dry air or 10% humidified air) and current conditions (no current or 0.75 A/cm2 cathodic current) are imposed. It is found that both humidity and cathodic current promote chromium poisoning. Microstructural characterizations also confirmed that larger amounts of chromium-containing deposits are present at the cathode/electrolyte interfaces of the cell tested with cathodic current and/or humidity.Free energy minimization calculations and thermogravimetric experiments are performed to determine the chromium vapor species that form over chromia-forming alloy interconnect and result in chromium deposition. Based on the experimental and computational results, the roles of humidity and cathodic current in chromium poisoning are evaluated, and a mechanism associated to chromium vapor species deposition at the cathode/electrolyte interface is proposed.

Surface composition and structure of divertor tiles following the JET tokamak operation with the ITER-like wall

Samples extracted from several divertor tiles following the 2011–2012 operation of JET with the ITER-Like wall were analyzed using ion beam analysis methods, x-ray fluorescence spectroscopy, scanning electron microscopy with energy dispersive spectroscopy analysis and x-ray diffraction. The emphasis was on the determination of light species and on material mixing including compound formation on the bottom and the outer divertor tiles. Deposition of deuterium, beryllium, carbon, nitrogen, oxygen, iron, chromium, nickel and molybdenum has been detected on all studied tiles. The thickest deposition, of around 4 µm, was measured on the bottom of the outer divertor, whereas the other surfaces (inner bottom and vertical outer) the co-deposits were around 1 µm. x-ray diffraction measurements have revealed the formation of the compound W2C on all specimens.

Low-Temperature Chromium Poisoning of SOFC Cathode

Chromium poisoning of SOFC cathode has been studied at 650 °C utilizing an electrochemical half-cell configuration (Air-3%H2O-CrOxHy /LSM//YSZ/Ag/Air). While the cell performance and electrode impedance show continued improvement with time under standard conditions (3% H2O-air), cell performance degrades rapidly in the presence of gaseous chromium as indicated by increase in the electrode polarization and reduction in the current with time. Scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDS) analyses for the cell exposed to chromium vapor shows chromium deposition on the cathode/electrolyte interface, no chromium was detected on the cathode surface and the interface of the cathode/electrolyte for the standard cell. Calculated equilibrium vapor pressures of chromium vapor species formed from pure chromium oxide (Cr2O3) under flowing humidified air (3% H2O-air) show that the partial pressure of major chromium specie namely CrO2(OH)2 at low temperature still remains appreciable and a cause for concern during long term operation of low-temperature SOFC.

Using Moss to Assess Airborne Heavy Metal Pollution in Taizhou, China.

Bryophytes act as bioindicators and bioaccumulators of metal deposition in the environment. To understand the atmospheric deposition of heavy metals (cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), and zinc (Zn)) in Taizhou, East China, samples of moss (Haplocladium microphyllum) were collected from 60 sites selected by a systematic sampling method during the summer of 2012, and the concentrations of these heavy metals were determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The results suggested that the concentrations of these metals varied moderately among different sites, indicating a similar contamination level for each element throughout the monitoring region. The mean values under investigation were higher than those from neighboring cities, such as Wuxi, Xuzhou, and Nanjing, and much higher than those in Europe based on a 2010 survey. Significant (p < 0.01) correlations were identified among some of the heavy metals, suggesting that these originated from identical sources. There was no statistically significant correlation between Hg and all the other elements. Spatial distribution maps of the elements over the sampled territory were created using Arc-GIS 9.0. The potential ecological risk index indicated that the air was heavily polluted by Cd and Hg, and that there was a considerable potential ecological risk from all the heavy metals studied.

Potentiodynamic Chromium Deposition from Trivalent and Hexavalent Systems on Glassy Carbon Electrodes: Initial Stages and Mechanistic Insights

AbstractDeveloping a functional Cr(III) electrolyte to replace carcinogenic and toxic Cr(VI) electroplating requires a deeper understanding of the deposition mechanisms. Hence, this study investigates and compares the growth of chromium on inert glassy carbon (GC) electrodes from low‐concentration Cr(III) and Cr(VI) electrolytes, using a novel potentiodynamic deposition scheme. This allows the initial stages of deposition to be probed, which are crucial for determining the overall deposition mechanism. Scanning electron microscopy shows that, for both systems, micrometer‐sized hexagonal chromium hydride crystals could be deposited on GC, thus serving to be the first reporting of such structures. In addition, by increasing the deposition time, the changes in a particle structure for both systems were tracked; therefore, possible areas of similarity as well as key differences could be identified, which, when addressed may provide a more viable, environmentally friendly trivalent electrolyte for chromium electroplating.

Hybrid laser technology and doped biomaterials

Hybrid laser-based technologies for deposition of new types of doped thin films are presented. The focus is on arrangements combining pulsed laser deposition (PLD) with magnetron sputtering (MS), and on the setup with two simultaneously running PLD systems (dual PLD). Advantages and disadvantages of both arrangements are discussed. Layers of different dopants concentration were prepared. Experience with deposition of chromium and titanium doped diamond-like carbon (DLC) films for potential coating of bone implants is presented. Properties of the layers prepared by both technologies are compared and discussed. The suitability of the layers for colonization with human bone marrow mesenchymal stem cells and human osteoblast-like cells, were also evaluated under in vitro conditions.

Experimental patch testing with chromium-coated materials.

Chromium coatings on metal alloys can be decorative, and prevent corrosion and metal ion release. We recently showed that handling of a chromium-containing disc resulted in chromium deposition on the skin. To examine patch test reactivity to chromium-coated discs. We included 15 patients: 10 chromium-allergic patients, and 5 patients without chromium allergy. All were patch tested with potassium dichromate, cobalt chloride, nickel sulfate, and nine different metallic discs. The chromium-allergic patients were also patch tested with serial dilutions of potassium dichromate. Positive/weaker reactions were observed to disc B (1 of 10), disc C (1 of 10), and disc D, disc E, and disc I (4 of 10 each). As no controls reacted to any of the discs, the weak reactions indicate allergic reactions. Positive patch test reactions to 1770 ppm chromium(VI) in the serial dilutions of potassium dichromate were observed in 7 of 10 patients. When the case group was narrowed down to include only the patients with a current positive patch test reaction to potassium dichromate, elicitation of dermatitis by both chromium(III) and chromium(VI) discs was observed in 4 of 7 of patients. Many of the patients reacted to both chromium(III) and chromium(VI) surfaces. Our results indicate that both chromium(VI) and chromium(III) pose a risk to chromium-allergic patients.

Modelling Dispersion Influences on Chromium Transport in Heterogeneous Silty and Fine sand Formation, Port Harcourt Industrial Lay-Out, Rivers State of Nigeria

This paper examined chromium transport through dispersion and storage coefficient influences. The study has monitored the deposition of chromium in silty and fine sand formation. The developed model expressed the behaviour of chromium in the study location, storage coefficient and dispersions of chromium were examined through the behaviour of chromium transport in silty and fine sand formation, the behaviour were expressed through graphical representation, the fluctuation on concentration reflect the influences from porosity variation thus dispersion and storage coefficient. This generated slight accumulation of chromium deposition in silty and fine sand formation, this condition was examined through the rate of chromium deposition; some fluctuations were experienced from the experimental values for model validation. The heterogeneous settings in the formation were also observed, the developed model was compared with other experimental values, and both parameters expressed favourable fits validating the model.

Branch bark of holm oak (Quercus ilex L.) for reconstructing the temporal variations of atmospheric deposition of hexavalent chromium

The bark from the annual segments of the branches of holm oak (Quercus ilex L.) is exposed to trace element deposition for a known period of time and thus it is a possible candidate as a bioindicator for reconstructing historical changes in pollution. A series of samples were analysed for Cr(VI) concentration by electrothermal atomic absorption spectrometry (ET-AAS) after selective extraction in a sodium carbonate solution. In this way the atmospheric deposition of Cr(VI) was reconstructed from 2001 to 2010 in an area where an industrial plant produced Cr(VI) compounds until 2003. The present study shows the potential of this type of sample as a natural archive for persistent pollutants, useful for monitoring changes that occur before a monitoring programme is established, with the advantage of being easy to collect almost everywhere.

Degradation of (La,Sr)(Co,Fe)O3-Δ SOFC Cathodes at the Nanometre Scale and below

For developing solid oxide fuel cells operating at intermediate temperatures (ITSOFCs), metallic materials have become a preferential choice for the interconnect due to their low cost and excellent physical and chemical properties. However the presence of chromium in all commonly used metallic alloys has been found to cause poisoning of the cathode leading to rapid electrochemical performance degradation of the cathodes including one of the most promising (La,Sr)(Co,Fe)O3-δ (LSCF) perovskite oxides [1-3]. Despite the extensive research on the chromium deposition and poisoning processes, careful microstructural studies, especially at the nanoscale, are rare, which can provide valuable information for the fundamental understanding of the Cr poisoning mechanisms required for developing Cr tolerant cathode materials. In this paper, we examine the Cr poisoning mechanisms in (La0.6Sr0.4)0.95(Co0.2Fe0.8)O3-δ (LSCF6428) materials by correlating the bulk electrochemical properties of the cell with their structural and chemical change at multi-scales down to the nanometer level. Cells with LSCF cathodes were prepared, and the effect of Cr poisoning on the electrochemical behavior of the cell was assessed by impedance spectroscopy. The change in nano/microstructure and chemistry due to poisoning were studied in parallel by a combination of advanced ion and electron microscopy techniques including focus ion beam (FIB) tomography, high resolution (scanning) transmission electron microscopy ((s)TEM) and analytical STEM. The systematic combination of bulk and high-resolution analysis on the same cells allows, for the first time, to directly correlate Cr induced performance degradation with subtle and localized structural/chemical changes of the cathode down to the atomic scale. Up to two orders of magnitude reduction in conductivity, oxygen surface exchange rate and diffusivity were observed in Cr poisoned LSCF6428 samples. These effects are associated with the formation of nanometer size SrCrO4; grain boundary segregation of Cr; enhanced B-site element exsolution (both Fe and Co); and reduction in the Fe valence, the latter two being related to Cr substitution in the LSCF phase. The finding that significant degradation of the cathode happens before obvious microscale change points to new critical SOFC degradation mechanisms effective at the nanometer scale and below, which provide new insight for the development of future poisoning resistant electrode materials not only for SOFCs but also for other devices such as solid oxide electrolysis cells.

Formation of chromium composite electrochemical coatings from sulfate oxalate solutions based on Cr(III)

The mechanism responsible for the inclusion of Al2O3 and SiC nanoparticles, the mixture of Nb2N and Ta2N (1: 1), MoS2, Cr2O3, and SiO2 with diverse electric conductivity, hydrophilicity, and resistance to solution components in chromium deposits from the sulfate–oxalate suspension solutions based on Cr(III) was studied. The main factors that determine the formation of chromium composite electrochemical coatings, their composition, and surface morphology were determined. The film on the surface of the growing deposit of the intermediates of the reduction of chromium ions plays the key role in the formation of composite coatings from Cr(III) and Cr(VI) sulfate–oxalate suspension solutions. The film can play the role of a structural mechanical barrier that hinders the incorporation of particles in the deposit, or it can fix the particles on the electrode surface by creating hydroxo bridges with chemisorbed hydroxide compounds on the particle surface.

Technology improvement of chromium on steel parts electrodeposition using complex command and control systems

The paper aims to provide improved technological process of electrochemical deposition of chromium on steel for decorative parts for corrosion protection but also to improve mechanical properties. The proposed idea is perfectly suited to be grafted onto existing electrodeposition installations, but it can be applied successfully in the development of new such plants. Complex command and control systems are designed to operate in high aggressive environmental conditions specific to these types of installations. The theoretical part completes the experimental results obtained on a laboratory facility.

A comparison study of chromium deposition and poisoning on La0.8Sr0.2Ga0.8Mg0.2O3−δ and Gd0.1Ce0.9O2−δ electrolytes of solid oxide fuel cells

The Cr deposition and poisoning on electrolyte of solid oxide fuel cells (SOFCs) is critical because the electrolyte at cathode side is exposed to gaseous Cr species. A comparison of Cr deposition and poisoning on La0.8Sr0.2Ga0.8Mg0.2O3−δ (LSGM) and Gd0.1Ce0.9O2−δ (GDC) electrolytes is studied, in order to reveal the compatibility of SOFCs. The XPS results show that the little Cr deposition on GDC surface at 800 °C is likely caused by physical deposition. In the case of LSGM surface, Cr deposition is also physical deposition process at 600 °C and 700 °C, while both physical and chemical deposition processes at 800 °C. Moreover, the obviously reduced electrical conductivity by Cr poisoning is obtained on LSGM rather than GDC. The results indicate that the GDC electrolyte promises higher Cr tolerance than LSGM electrolyte.

The impact of a high magnitude flood on metal pollution in a shallow subtropical estuarine embayment

Drought-breaking floods pose a risk to coastal water quality as sediments, nutrients, and pollutants stored within catchments during periods of low flow are mobilized and delivered to coastal waters within a short period of time. Here we use subtidal surface sediment surveys and sediment cores to explore the effects of the 2011 Brisbane River flood on trace metals zinc (Zn), lead (Pb), copper (Cu), nickel (Ni), chromium (Cr), manganese (Mn), and phosphorus (P) deposition in Moreton Bay, a shallow subtropical bay in eastern Australia. Concentrations of Zn, Cu, and Pb in sediments in central Moreton Bay derived from the 2011 flood were the highest yet observed in the Bay. We suggest flushing of metal rich sediments which had accumulated on the Brisbane River floodplain and in its estuary during the preceding 10 to 40years of low flows to be the primary source of this increase. This highlights the importance of intermittent high magnitude floods in tidally influenced rivers in controlling metal transport to coastal waters in subtropical regions.

The Stillwater Complex, Montana – Overview and the significance of volatiles

AbstractThe geology of the 2.7 Ga Stillwater Complex in South-Central Montana is reviewed with a focus on the role of volatiles in locally modifying both the crystallization sequence of the evolving parent magma and the initially precipitated solid assemblages to favour olivine ± chromite. A secondary origin for these two minerals is particularly probable for the olivine-bearing rocks of the Banded series and, at a minimum, also increasing their modal abundance in the Peridotite zone of the Ultramafic series. Direct evidence for volatiles includes the presence of high-temperature fluid inclusions in pegmatoids and hydrous melt inclusions (now crystallized) in chromite and olivine from both the Ultramafic and the Banded series rocks. Indirect evidence includes the boninitic character of the parent magma, the presence of volatile-bearing minerals including high-temperature carbonates, rock textures, and Cl / F variations in apatite. Mechanisms which favour the formation of olivine (± chromite) over pyroxene include volatile phase boundary shifts induced by added H2O, incongruent melting of pyroxene by hydration of a partly-molten mush, and the near- to sub-solidus replacement of pyroxene by olivine and chromite by silica-undersaturated fluids. These mechanisms cast doubt that magmas with different liquid lines of descent were involved in the crystallization of the Stillwater Complex. A dry Stillwater magma would have been mineralogically and modally much less varied and lacking in high-grade platinum-group element and chromium deposits.

Experimental skin deposition of chromium on the hands following handling of samples of leather and metal.

Chromium is an important skin sensitizer. Exposure to it has been regulated in cement, and recently in leather. Studies on the deposition of chromium ions on the skin as a result of handling different chromium-containing materials are sparse, but could improve the risk assessment of contact sensitization and allergic contact dermatitis caused by chromium. To determine whether the handling of chromium-containing samples of leather and metal results in the deposition of chromium onto the skin. Five healthy volunteers participated. For 30 min, they handled samples of leather and metal known to contain and release chromium. Skin deposition of chromium was assessed with the acid wipe sampling technique. Acid wipe sampling of the participants' fingers showed chromium deposition on the skin in all participants who had been exposed to leather (range 0.01-0.20 µg/cm(2) ) and in 3 of 5 participants after they had manually handled metal discs (range 0.02-0.04 µg/cm(2) ). We found that samples of leather and metal had the ability to deposit chromium on the skin at significant levels, in spite of a short duration of exposure.