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1.
《文物保护研究》2013,58(4):232-240
AbstractThe method of removing chlorides from archaeological iron objects using hydrogen plasma at low pressure has been studied and improved. To carry out the initial experiments and to limit the use of ancient material, synthetic samples were made from iron powder and corrosion products consisting mainly of akaganeite. The time and the temperature required for the complete removal of the chlorides were determined. It was also possible to demonstrate that magnetite, and iron above 400°C, are the final reaction products of the reduction of akaganeite. 相似文献
2.
《文物保护研究》2013,58(4):326-337
AbstractAlthough desalination of archaeological iron reduces its chloride concentration and enhances object stability, the reduction in corrosion rate that this produces has never been quantified. This study measures post-treatment corrosion rates in accelerated corrosion environments to identify the impact of removing chloride ions on corrosion rate. Thirty-five archaeological iron nails, treated individually in either alkaline sulphite or nitrogen-deoxygenated sodium hydroxide, were exposed to 75°C and 75% relative humidity together with 31 untreated objects from the same archaeological sites. Object weight change and visual examination of physical change before and after the test period were used to monitor corrosion. 77% of treated objects showed no weight gain and no visible signs of corrosion, while 90% of untreated objects did corrode. The impact of chloride on corrosion of untreated objects was clearly established by a significant linear correlation between chloride content and weight gain. Treated objects with <400 ppm chloride content showed no corrosion behaviour. Corrosion of treated objects was attributed to incomplete treatment: 93% of objects treated to <5 mg/l Cl? in the final solution bath displayed no corrosion behaviour. Based on these results, desalination of iron objects to enhance their stability offers a valuable option for reducing corrosion rates of archaeological iron, which should increase object lifespan. The results also raise the question of whether low levels of post-treatment residual chloride produce corrosion of any significance. Answering this will be an important step forward for managing the preservation of archaeological iron. 相似文献
3.
《文物保护研究》2013,58(1):29-41
AbstractChloride-contaminated archaeological iron is unstable and problematic to store and display within museum collections. Reducing its chloride ion content using aqueous desalination followed by storage in controlled relative humidity offers one treatment option. This study reports a quantitative assessment of chloride extraction by aqueous deoxygenated alkaline desalination solutions from 120 individual archaeological iron nails. The three treatment methods comprised alkaline sulphite solution (0.1 M NaOH/0.05 M Na2SO3) at room temperature and at 60°C and sodium hydroxide solution (0.1 M) deoxygenated using a nitrogen gas positive pressure system at room temperature. Chloride extraction was monitored using a specific ion meter. The nails were digested after treatment to measure their residual chloride content. A wide range of extraction patterns emerged, with the majority of individual treatments extracting 60–99% of the chloride present. Residual chloride levels for 87% of the objects fell below 1000 ppm and 42% were below 200 ppm. Although no treatment extracted 100% of the chloride in the object, alkaline desalination produced very significant reductions in chloride content. The impact of this on future corrosion of the objects is discussed. This quantitative and statistically viable assessment of deoxygenated desalination treatments provides evidence to support their use in conservation practice, which will impact on procedures for the preservation and management of archaeological heritage. 相似文献
4.
《文物保护研究》2013,58(2):125-134
AbstractA small but significant proportion of the archaeological iron objects in the British Museum collection have been problematic in that some of them have required repeated treatment. The deterioration of iron objects during storage was studied using microscopy, Raman spectroscopy, X-ray diffraction, scanning electron microscopy/energy dispersive X-ray analysis, X-ray fluorescence spectroscopy and ion chromatography. A total of 125 iron objects, including 56 from two British Roman sites and 69 from three Anglo-Saxon sites, were studied. Both surface corrosion and corrosion layers on polished cross-sections were investigated. The study revealed that the present condition of the iron objects varies; some are in a stable condition and others have been deteriorating, with pitting and weeping present on the surface. No treatment method had stopped corrosion for every object, although the alkaline sulphite treatment seemed to be more effective than the other methods. The results also showed that chloride ions can be present at the interface of the metal and inner corrosion layers. It is recommended that iron objects which have been mechanically cleaned without desalination treatments are kept in a dry environment to prevent further deterioration. 相似文献
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6.
《文物保护研究》2013,58(4):227-236
AbstractThis article compares chemical dechlorination treatments (immersion in sodium hydroxide or alkaline sulphite) and electrochemical treatments of iron bars from the Gallo-Roman period excavated from a marine environment. Some important parameters, such as storage before treatment, temperature, solution composition, and drying after treatment, were varied during the study to assess their influence on the chloride extraction process. The kinetics of these treatments depend mainly on chloride diffusion through the corrosion layers. The kinetics are promoted by high temperatures and, in the case of electrolysis, by the electric field effect. The reduction of corrosion products during electrolysis occurs only for objects previously stored in air. In fact, the manner in which the objects are stored before treatment is critical in the dechlorination processes. The sooner the objects are treated after excavation (with water storage), the better the removal of chloride ions, in both chemical immersion and electrolysis treatments. But if the object is stored in air, material losses occur, and only electrolysis results in complete extraction of the chlorides. These differences are due to modifications in the corrosion products during storage. Drying after treatment also has a significant impact on the composition of the corrosion layers. If the objects are dried too quickly, Fe(OH)2 oxidizes into FeOOH, which thus forms a layer with low cohesion. 相似文献
7.
《文物保护研究》2013,58(3):274-282
AbstractA study of the composition and phase distribution of the corrosion layers on three ferrous objects, excavated at K2 (Bambandyanalo), an archaeological site in South Africa, was conducted. The objective of the study was to obtain information that can contribute to conservation procedures to be performed on the iron artefacts from this site. Examination of cross sections by means of energy-dispersive X-ray spectroscopy coupled to a scanning electron microscope (SEM–EDX), X-ray powder diffraction (XRD), and micro-Raman spectroscopy revealed the same corrosion composition and structure for all the objects under study, namely an internal layer adjacent to the metal surface with ghost inclusions and an external layer containing quartz grains. The study also revealed that the presence of magnetite (Fe3O4), maghemite (γFe2O3), and lepidocrocite (γ-FeOOH) within the internal layer is the only difference between the chemical compositions of iron corrosion products within the two layers. The results also made it possible to retrace the corrosion history during burial and long-term storage. 相似文献
8.
《文物保护研究》2013,58(2):110-119
AbstractSilver oxide is currently used to treat isolated spats of bronze disease, forming a seal of silver chloride. The technique is not infallible: an analytical study showed that the conductive properties of the silver chloride seal, together with the comparatively poor moisture barrier formed, are the factors responsible for failure. In the new zinc dust treatment proposed, tough, adherent and relatively stable zinc compounds form an improved barrier, effectively sealing the area of bronze disease. Objects treated with zinc dust were subjected to high humidity for several months and afterwards exposed to a tropical humid environment for four to five years. These objects showed no re-emergence of bronze disease whereas repeated use of silver oxide failed to stabilize the objects. The method developed is simple, less time-consuming, and relatively easy to employ. 相似文献
9.
《文物保护研究》2013,58(3):155-171
AbstractThe presence of iron oxides (lepidocrocite, goethite) in archeological wood may result in a degradation of the wood matrix. Extraction of these iron oxides is largely dependent on their solubility. In this study, balsa wood samples were impregnated with iron oxides to test extraction treatments. Additionally, archeological wood samples were also examined to determine treatment efficiency. Electrophoresis and simple immersion treatments were performed using various chemical solutions: a neutral and a conductive substance (potassium nitrate), an acid (acetic acid), three alkaline chelating agents (tri-ammonium and tri-sodium citrate and sodium oxalate), three acidic and slightly acidic chelating agents (ethylenediaminetetraacetic acid (EDTA), citric acid, and oxalic acid), and a reductant (sodium dithionite). Potassium nitrate did not extract sufficient amounts of iron, irrespective of whether the treatment was conducted by electrophoresis or simple immersion; any observable dissolution was attributed to protonation because of the acidic pH around the anode (as low as 3). Dissolution in acetic acid did not extract iron with either treatment. Strong chelating agents improved extraction, and these compounds gave the best results for simple immersion, particularly EDTA. This chemical is well adapted for use on archeological objects because of its chemical properties (stability constant, speciation based on pH). The addition of sodium dithionite to the solution improved dissolution. Even though electrophoresis improved extraction (in particular for tri-ammonium citrate), none of the tested chelating chemicals were suitable for electrophoresis because of a significant increase in temperature as well as high anode corrosion. The presence of iron sulfide in the archeological wood limited the effectiveness of the tested chemicals. A pre-treatment in sodium persulfate was expanded to include oxidized iron sulfide in oxy/hydroxide iron, which improved the extraction rate. 相似文献
10.
AbstractThe long-term stabilization of marine archaeological iron, whether cast or wrought, continues to challenge conservators responsible for treatment of this material. Results and observations obtained from past treatments highlight the daunting, prolonged, and laborious efforts required to desalinate large and complex ferrous artifacts recovered from the ocean. In general, the higher an artifact's chloride level, the less stable it is. Consequently, any stabilization treatment must involve the removal of as much Cl?1 as possible without affecting the integrity of the corroded artifact. This problem is particularly acute with corroding cast iron objects that have formed thick, fragile, and highly unstable corrosion layers. Over the course of the twentieth century, conservators have used a variety of techniques in an attempt to mitigate the negative effects of chloride ions on iron artifacts and prevent disintegration. In spite of early promise, each of these stabilization techniques has significant disadvantages, particularly with regard to treatment efficiency, duration of treatment, and/or unacceptable risks to the artifact during treatment. For these reasons, conservators and conservation scientists at the Warren Lasch Conservation Center in Charleston, South Carolina, decided to look at the possibility of using subcritical fluids to stabilize archaeological iron. This paper compares the efficiency and effectiveness of traditional stabilization techniques (i.e. alkaline soaking and cathodic polarization) to subcritical fluids on wrought iron rivets and metal shavings from the H.L. Hunley submarine as well as Civil War era cast iron artillery shells recovered from a marine environment. 相似文献
11.
《文物保护研究》2013,58(3):136-142
AbstractVarious desalination methods had been used in the past to treat a large collection of archaeological iron objects. In order to establish whether desalination treatments had been effective, the condition of the objects was assessed and the data analyzed using statistical methods. It was found that objects which had been treated using desalination methods were less likely to re-corrode, and the conclusion was that the development of more effective techniques of chloride removal would be useful. 相似文献
12.
《文物保护研究》2012,57(1):28-36
ABSTRACTA pre-restoration diagnosis revealed a high amount of pyrite in the wood of the Lyon Saint-Georges 4 shipwreck (end of the second century). The occurrence of this phase is supposed to result from the microbiologically influenced corrosion of the iron fasteners. So, all the nails and metallic elements were removed from the remains before treatment and the wreck was consolidated by polyethylene glycol impregnation coupled to a specific desalination process. Treated and non-treated samples extracted from the wreck were studied in order to identify the iron/sulfur-containing compounds present in the wood before and after treatment and figure out its effect. Sample analyses relied on an original approach combining magnetic characterization methods and more common elemental and structural analysis methods. The results showed that the treatment was effective in removing soluble salts. However, a large amount of unstable iron sulfides remained inside the wood. 相似文献
13.
《文物保护研究》2013,58(3):179-190
AbstractTesting of chemical stabilization treatments and desiccated and anoxic storage microclimates for the protection of archaeological iron stored in unsuitable climatic conditions was carried out by the conservation department of the Japanese Institute of Anatolian Archaeology at the Kaman-Kalehöyük excavation in Turkey. The chemical stabilization treatments involved alkaline sulfite, barium hydroxide and sodium hydroxide. Environmental stabilization was explored using RP-A oxygen scavengers in Escal® bags as part of the Revolutionary Preservation System (RP System®) manufactured by Mitsubishi Gas Chemical Company, Inc. The efficiency of the chemical treatments was examined by comparison with mechanically cleaned iron objects. The efficiency of the storage systems was determined by comparing the chemically and non-chemically treated objects in the RP System® using RP-A scavengers and in polyethylene ziplock bags containing silica gel. The efficiency of these treatments and storage systems was examined and assessed at Kaman after a period ranging from 7 to 9 years. The anoxic and desiccating properties of the RP System® resulted in superior protective qualities over polyethylene bags with silica gel. The RP System® compensated for inadequate chemical stabilization and protected iron that had not been chemically stabilized. 相似文献
14.
《文物保护研究》2013,58(3):180-197
AbstractCorrosion rates are presented for metals in the aqueous solutions intended for treating both the wood and the metal components of a waterlogged wood-metal composite object. The metals include lead, mild steel, cast iron and the copper alloys of bronze, cast brass and wrought brass. The corrosion rates were determined using a standard weight-loss method in which clean metal surfaces were immersed in the solutions for two months at room temperature. The treatment solutions included Acrysol® G-11O for lead, Witcamine® RAD 1100 for copper alloys and Pluracol® 824 or the corrosion inhibitor Hostacor® KS 1 in PEG 400 for iron. These treatment solutions were prepared in distilled water as well as in a synthetic seawater. For reference, metal corrosion rates were also determined in distilled water, synthetic seawater and PEG 400. The results demonstrate that, in general, clean metal surfaces corrode more slowly in the treatment solutions than in PEG 400 solutions. However, before recommending these solutions for the treatment of composite objects, further testing is needed to determine how effective they are in reducing the corrosion rates of metals covered with a thick corrosion crust, and to see if Acrysol G-110 is capable of bulking and consolidating waterlogged wood. 相似文献
15.
《文物保护研究》2013,58(4):226-232
AbstractCarbonyl compounds are of concern in museums because of their potential to damage artifacts. The mode of damage for aldehydes is far from clear and seems to require oxidation. Lead coupons were exposed to gaseous formaldehyde (methanal) and formic acid (methanoic acid) in various humid oxidizing atmospheres. The resulting corrosion products were weighed and identified using X-ray diffraction analysis after as much as 56 days exposure. When fomaldehyde was in more oxidizing environments (atmospheres containing hydrogen peroxide) it caused heavy corrosion but in the dark, with no oxidant, there was only very slight tarnish, even at high humidities. This suggests that oxidation is an important control on corrosion by formaldehyde. Thermodynamic calculations indicate that at low formic acid concentrations (below about 1 ppb) the corrosion products should be carbonates (plumbonacrite and hydrocerussite) while at higher concentrations lead formate would be expected. The mineralogical complexity and the importance of oxidants make it very difficult to set standards for formaldehyde in the museum environment. 相似文献
16.
Tiziana Lombardo Marie Wörle Vera Hubert Erwin Hildbrand Christina Hinterleitner Ingo Mayer 《文物保护研究》2020,65(2):65-76
ABSTRACTPreviously, heavy use of biocides for the treatment of objects made of organic materials in museum collections (e.g. ethnographic, historical collections) was very common. Now suitable decontamination methods/technologies are being sought. A decontamination treatment by li-CO2 was optimized that considered the specific requirements of museum objects. The treatment was tested on model materials artificially contaminated with biocide solutions containing dichlorodiphenyltrichloroethane (DDT), pentachlorophenol (PCP), lindane, and permethrin or cypermethrin. High decontamination was achieved for DDT, lindane, PCP, and permethrin on artificially biocide loaded wool and wood model materials. Optimal process parameter settings for li-CO2 decontamination include a single 30?min cycle for woolen materials and three sequential 30?min cycles each for wood. These methods allow a reduction of at least 90% of all biocides for wool and between 70% and 85% for wood. Decontamination of the latter was more effective for less polar biocides as DDT and permethrin. Despite a significant improvement in decontamination for wood using co-solvents such as acetone, ethanol, and methyl tertiary-butyl ether (MTBE), their use is not recommended due to the increased risk of damage to the objects, in particular if a surface coating is present. 相似文献
17.
AbstractThe use of sodium nitrite (NaNO2) as a corrosion inhibitor for wet archeological metal objects presents potential advantages of near neutral pH, low concentration, effectiveness on several metals, and compatibility with organic materials. The effectiveness of NaNO2 as a corrosion inhibitor for storage of chloride-containing marine archeological metal objects from the wreck of the USS Monitor was evaluated using marine-corroded carbon steel analogs. The samples were tested in varying concentrations of NaNO2 and evaluated visually and by monitoring solution chemistry using ion chromatography (IC). It was found that a concentration of 1000 ppm NaNO2, replaced four times, was effective at protecting corroded carbon steel in the presence of chlorides. Nitrite solutions were no more rapid than sodium hydroxide (NaOH) at extracting chlorides from marine steel at equal concentrations and were considerably slower than 2% NaOH. IC analyses indicated that NO2 does not easily oxidize to NO3 under normal conditions, but does so readily when a polarizing current is applied, making nitrites unsuitable for electrolytic reduction treatments. Sodium nitrite does show promise as a storage solution prior to desalination of marine metals or after desalination to prevent flash corrosion during rinsing baths. 相似文献
18.
《文物保护研究》2013,58(3):201-210
AbstractThirty artists' colors have been exposed for 12weeks to 120ppb of formaldehyde in purified air as well as to purified air alone (control experiment). The exposure was carried out in the dark at ambient temperature (19 ± 2°C) and humidity (RH 44–52%). Color change (?E) was measured using a reflectance color analyzer after one, two, three, four, six, eight, 11 and 12 weeks of exposure. Color parameters (x, y, X, Y, Z, L*, a*, b* and ?E)"were also calculated from the 380–700nm spectra, recorded with a reflectance spectrophotometer, of unexposed colorants and of colorants exposed for 12 weeks to purified air and to formaldehyde. Regression analysis of the two data sets indicated that the color changes measured by these two methods were in excellent agreement (nearunity slopes, with correlation coefficients > 0.99). Exposure to either formaldehyde or pure air on watercolor paper resulted in little or no color change for all the colorants tested, including inorganic colorants, alizarin lakes, quinacridones, triphenyl methanes, indigo derivatives, arylamides and natural colorants such as curcumin. Formaldehyde, which is ubiquitous in indoor air, including museum air, does not appear to be a major threat to colorants in museum collections. 相似文献
19.
COMUNICÁO: TRAMA DE DESEJOS E ESPELHOS: OS METALURGICOS, A TELENOVELA E A COMUNICACÁO DO SINDICATO / COMMUNICATION: A PLOT OF HOPES AND DESIRES: METAL WORKERS, SOAP OPERAS, AND UNION COMMUNICATION by Maria Luiza Cardinale Baptista (Canoas, Brazil: Universidade Luterana do Brasil “Colecao Mundo Midia, No. 3,”; 1996—no price available, ISBN 85–85692–17–0, 180 pp., tables) LAS OTRAS RADIOS / THE OTHER RADIOS by Alfredo Bouissa, Eduardo Curuchet, and Oscar Orcajo (Montevideo, Uruguay: Editorial Nordan‐Comunidad “Coleccion Tierra Amiga, No. 3,”; 1998—no price available, ISBN 9974–42–052–5, 268 pp., appendices) AS HISTÓRIAS EM QUADRINHOS NO BRÁSIL: TEORIA E PRATICA / A HISTORY OF COMICS IN BRAZIL: THEORY AND PRACTICE edited by Flávio Mário de Alcântara Calazans (São Paulo: INTERCOM “Colecao GT's da INTERCOM, No. 7,”; 1997—price not given, ISBN 85–900400–1‐1, 174 pp.) CALANDRA: O SUFOCO DA IMPRENSA NOS ANOS DE CHUMBO /CALENDER: THE SUFFOCATION OF THE PRESS IN THE YEARS OF DICTATORSHIP by Pery Cotta (Rio de Janeiro: BCD União de editoras, Bertrand Brasil, 1997—no price available, ISBN 85–286–0610–4, 238 pp.) CINE Y MEMORIA DEL SIGLO XX CINE EN CHILE: CINE EN EL MUNDO: HISTORIA SOCIAL Y CULTURAL DE CHILE: HISTORIA SOCIAL Y CULTURAL MUNDIAL CUADROS SINOPTICOS (1895–1995) / FILM AND MEMORY OF THE 20TH CENTURY: FILM IN CHILE, FILM IN THE WORLD, SOCIAL AND CULTURAL HISTORY OF CHILE, SOCIAL AND CULTURAL HISTORY OF THE WORLD, 1895–1995 by Jacqueline Mouesca and Carlos Orellana (Santiago de Chile: LOM Ediciones “Coleccion Sin Norte,”; 1998—no price available, ISBN 956–282–077–7, 417 pp., photographs) CUENTO DE CINE / FILM STORIES edited by Sergio Renan (Buenos Aires: Extra Alfaguara, 1996—no price available, ISBN 950–511–259–9, 294 pp.) 相似文献
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Carteles de la Epoca de Oro del Cine Mexicano / POSTER ART FROM THE GOLDEN AGE OF MEXICAN CINEMA by Rogelio Agrasanchez, Jr. (Harlingen, TX: Archivo Filmico Agrasanchez, University de Guadalajara, Instituto Mexicano de Cinematografia/Austin, TX: University of Texas Press, 1997‐$40.00, ISBN 0–292–70485–2, 199 pp., photographs, index) PODER POLIÍTICO Y COMUNICACIÓN / POLITICAL POWER AND COMMUNICATION by Oswaldo Capriles Arias (Caracas: Universidad Central de Venezuela, Consejo de Desarrollo Cientifico y Humanistico “Colección Monografias 55,”; 1996‐no price available, ISBN 980–00–0978–7, 282 pp., notes, appendices) ECONOMIA POLÍTICA DAS TELECOMUNICACÓES, DA INFORMACÁO, E DA COMUNICACÓA / POLITICAL ECONOMY OF COMMUNICATION, INFORMATION, AND TELECOMMUNICATIONS edited by César Ricardo Siqueira Bolaño (Sáo Paulo: INTERCOM “Colecáo GT's Intercom 5,”; 1995‐no price available, no ISBN [OCLC 35889473], 170 pp., notes, tables) ESTADO E CINEMA NO BRASIL / THE STATE AND CINEMA IN BRAZIL by Anita Simis (Sáo Paulo: Annablume Editora “Selo Universidade, Ciencias Sociais 51,”; 1996‐no price available, ISBN 8–5855–9669–3, 312 pp., tables, notes, illustrations, photographs) LA CULTURA DA TRABAJO: ENTRE LA CREACIÓN Y EL NEGOCIO: ECONOMIA Y CULTURA EN EL URUGUAY / CULTURE CREATES JOBS: BETWEEN CREATIVITY AND BUSINESS: CULTURE AND THE ECONOMY IN URUGUAY by Luis Stolovich, Graciela Lescano, and José Mourelle (Montevideo: Editorial Fin de Sigio “Colección Referencias,”; 1997‐no price available, ISBN 9974–49–107‐X, 329 pp., tables, figures, notes) UN MUNDO SIN PERIODISTAS: LAS TORTUOSAS RELACIONES DE MENEM CON LA LEY, LA JUSTICIA Y LA VERDAD / A WORLD WITHOUT JOURNALISTS: THE TORTUROUS RELATIONS OF MENEM WITH THE LAW, JUSTICE AND TRUTH by Horacio Verbitsky (Buenos Aires: Editorial Pianeta, 1997‐no price available, ISBN 950–742–886–0, 430 pp., appendices) 相似文献