Copper and Bronze in Art: Corrosion, Colorants, Conservation

Abstract

loo CHAPTER 3 BASIC COPPER CARBONATES 102 Malachite Decorative uses of malachite Malachite as a copper ore Nomenclature confusion Mineral properties Malachite as a pigment Malachite in bronze patinas Isotope ratios to determine corrosion environment 108 Azurite Azurite as a corrosion product Azurite as a pigment Conservation issues for azurite 111 Formation of Copper Carbonates in Solution 113 Decomposition of Malachite and Azurite by Heat 113 Artificial Malachite and Azurite 114 Blue and Green Verditer Use of blue and green verditer in art Synthesis of blue and green verditer 116 Mixed-Cation Copper Carbonates Mixed copper-zinc carbonates in corrosion Synthetic pigments with copper and zinc salts 117 Chalconatronite: A Sodium-Copper Carbonate Synthesis and use of chalconatronite Chalconatronite as a corrosion product 122 CHAPTER 4 CHLORIDES AND BASIC CHLORIDES 122 The Copper Chlorides Nantokite Atacamite Paratacamite (anakarite) and clinoatacamite Botallackite 125 Copper Chlorides and Bronze Disease Bronze disease research Role of chloride ions in corrosion Pitting corrosion 134 The Basic Copper Chlorides as Pigments Synthetic pigments Pigment morphology 139 Other Basic Copper Chlorides Connellite Calumetite Anthonyite Cumengite and mixed copper-lead chlorides Mixed copper-zinc chlorides \ Other mixed-cation copper chlorides 145 | CHAPTER 5 BASIC SULFATES 146 Historical References to Copper Sulfates 147 The Basic Copper Sulfates Brochantite and anderite Posnjakite Other basic sulfates 154 Environment and Corrosion Atmospheric sulfur dioxide Microenvironment and corrosion 159 Case Studies of Exposed Bronzes The Statue of Liberty The Great Buddha at Kamakura Gettysburg National Military Park bronzes Brancusi's Infinite Column 164 Sulfate Deposition in Burial Environments 165 Basic Sulfates as Pigments 169 PLATES 224 | CHAPTER 6 COPPER SULFIDES 226 The Chemistry of Copper Sulfides 227 Corrosion Environments and Copper Sulfide Production Sulfide formation in reducing environments Sulfide formation from atmospheric exposure Sulfide formation from pollution in the museum environment 235 Copper Sulfides and Niello Niello recipes Artifacts decorated with niello Niello chemistry 240 | CHAPTER 7 COPPER PHOSPHATES AND COPPER NITRATES 240 The Copper Phosphates Copper phosphate chemistry Copper phosphate corrosion in different environments Sampleite and the arid environment Pseudomalachite: A copper phosphate pigment 246 Turquoise The chemistry and mineralogy of turquoise The history of turquoise 250 The Copper Nitrate Minerals Copper nitrate corrosion products 252 | CHAPTER 8 COPPER SILICATES 253 Chrysocolla Chrysocolla as a pigment 255 Dioptase 255 Copper Silicates and Glasses 257 Egyptian Blue and Other Synthetic Copper Silicates Geographic distribution of Egyptian blue Lost and found secrets of Egyptian blue Chemical formulation of Egyptian blue Egyptian green Terminology Pigment deterioration mystery 266 Han Blue and Han Purple: Synthetic Pigments from China 268 | CHAPTER 9 THE ORGANIC SALTS OF COPPER 269 The Copper For...

A study on ancient casting method through microstructures of impurities and copper found in bronze excavated from the Unified Silla Period

“…Layer 's electron diffraction pattern showed rings, indicating that it was polycrystalline. In general, tenorite (CuO) is not kinetically favored and is usually found in burned burial environments or slowly heated in air [14]. It was possible that the mercury amalgam method gilded the Buddha's robes and heated to a temperature at which mercury vaporized (638 K).…”

Raman Micro-Spectroscopic Investigation of Corrosion Products.

“…The copper acetate, Verdigris (Cu (CH3COO) -2 .Cu(OH)2) was present in the Raman spectra at 929, 935, 1060, 1413, 1551. The acetate ion in some of the corrosion products probably comes from one of two sources, from the wooden trays and cupboards used to store many objects after excavation, or from wood in the burial environment, or the wooden boxes that were sometimes used for the burial of groups of statuettes [25][26][27][28][29][30][31][32]. Casseterite (SnO2) is also observed at 112, 210, 477, 638, and 778 cm -1 , the first two bands are related to bulk Tin Oxide, while the last three bands are related to nano tin Oxide [21].…”

“…It is also noticed the presence of cerussite (PbCO3) at 109 cm -1 which could be attributed to corrosion of lead in the chemical structure of the alloy. During casting it is possible to get some segregation of the lead to the outer surface of the mold, with the result that there may be a prevalence of lead-containing corrosion products, such as the commonly encountered cerussite and hydrocerrusite, in the patina [25].…”

“…Gold acted as a cathodic terminal and copper is progressively corroded [24]. The cuprite layer is the usual component found below the gilding layer, and either carbonate or tri-hydroxy chloride compounds are found on the gilding layer, that turns it to a very fragile and porous [25][26]. The objective of this work is to identify the chemical structure of the gilt-bronze statuettes and measure the degradation mechanism in the burial environment by micro-Raman and Portable and Xray Fluorescence.…”

'Copper and Bronze in Art' and the Search for Rare Corrosion Products

“…"The book is a mine of information" commented the British Museum's Keeper of Conservation, William Andrew Oddy (2002), in his review of David A. Scott's highly prized and praised work 'Copper and Bronze in Art: Corrosion, Colorants, Conservation' (in the following referred to as SCOTT). One can rarely find a book which so deeply fulfills both the need of students new to the field for a comprehensible introduction and of researchers to identify the frontiers of knowledge.…”