Abstracts

Diran Apelian

Physical Metallurgy: Phase Diagrams

Phases in materials engineering will be defined and explained in this lecture, and the use of phase diagrams will be reviewed. Phase transformations will be discussed, and in particular invariant transformations such as eutectic and peritectic reactions will be reviewed in detail. Concepts of solubility limits, phase separation, intermetallics will be discussed and illustrated with the use of phase diagrams. Modern software tools that aid in navigating through complex alloy systems and determining the phases that precipitate out during solidification will also be reviewed, and case studies will be presented.

Ronald Biederman

Forensics Research with Metal Objects: WTC Steel Case Study

Several steel samples from Buildings 7, 1 and 2 of the World Trade Center were collected during the Federal Emergency Management Agency forensic investigation shortly after the September 11, 2001 incident. Macroscopically the steel samples supplied exhibited severe "erosion" with plate thickness varying from 12.7mm to a total loss of metal in many areas. Also, some localized plastic deformation was observed. A determination of the cause of this unexpected erosion and an estimate of the maximum temperature that this steel likely experienced are the subjects of this investigation.

David Edge

The Relationship between Curator and Conservator: Case Studies in Metals Conservation at the Wallace Collection

David Edge draws upon his thirty years’ experience as metals conservator/Armourer at the Wallace Collection in London to discuss various aspects of the relationship between curator and conservator, as they exist within the museums profession. Topics covered will include the conception, planning and implementation of exhibitions, formulation of conservation policy, conservation ethics and the decision-making process that governs the extent to which ‘restoration’ is allowable, matters of gallery display, handling of objects (including the creation and maintenance of ‘handling collections’ intended for use by the public), and museum storage. Wherever possible, these topics will be illustrated through reference to (recent) past history and known (or not so known!) examples drawn from the conservation records and archives of the Wallace Collection.

Jeffrey Forgeng

Metals and the Martial Imagination

Since the advent of bronze over 5,000 years ago, metals have conferred enormous military advantages for those who could effectively produce, craft and deploy them. In part due to their practical usefulness, in part due to their esthetic possibilities, metals also acquired powerful symbolic power: even a relatively ordinary metal like iron enjoyed a measure of mystique. This presentation will examine the imaginative history of metals in martial contexts from the golden helmets of Mesopotamia to the intricate military devices of Leonardo da Vinci, with a walk-through of the Higgins collections that will highlight the relationship between metals and the martial imagination.

Susanne Gänsicke

Introduction into metals conservation

The different major metals and their alloys will be reviewed with a brief survey of their introduction and use over time. Conservation problems and treatment approaches vary widely based on the physical circumstances from which an artifact originated as well as its cultural and historical background (archaeological, ethnographic, decorative arts, architectural or industrial). The need for conservation and treatment of metal objects stems not only from the original techniques and materials employed in their of manufacture, from use and prior repair, but also from the subsequent history of the items, which may have involved burial, exposure to moisture or fire, or to various chemical environments. Treatments ranging from surface cleaning to reduction of corrosion products and structural stabilization will be illustrated. Different philosophical approaches will be discussed in light of the original context of the artifact and its intended end use in a collection - on public view, in a teaching collection, as outdoor sculpture, or perhaps as functioning industrial heritage.

A brief history of the restoration and conservation of metal objects

People have repaired and cared for metal objects and artifacts since ancient times using whatever materials and techniques were available. Only in the late 19th century, however, did the professional discipline of modern metal restoration and conservation began to evolve as extensive amounts of archaeological metals were excavated and collections formed in museums. The development of treatment techniques will be reviewed, including chemical and electrochemical cleaning and stabilization methods, mechanical approaches, and as well as more recent techniques that involve the use of plasma or lasers. Current trends and ethics will be discussed, as will the growing importance of preventive conservation.

Edward Hunter

Introduction to arms and armor conservation

This talk will provide an introduction to the conservation of arms and armor, covering the history of arms and armor conservation, basic methods and materials, core knowledge and terminology, and will discuss a guiding philosophy of arms and armor conservation and restoration. Topics will include: methods and materials of cleaning, protective coatings, handling, safety, and mounting. The talk will also focus on the history of arms and armor conservation at the metropolitan museum of art and will look at how this field has changed over the last 100 years and what lessons remain pertinent today.

Ralph E. Napolitano

The Origin of Metals

The mere mention of extractive metallurgy conjures up the dramatic images of immense caldrons of fire and molten metal that were indelibly etched into the American culture during the industrial revolution of the 20th century. During this period, steel and its related products became a foundation upon which cities were raised, forging a brotherhood among those whose blood and sweat built the world’s first true industrial empire. Their efforts were rewarded through the explosion of innovation, invention, and production that ultimately swept the globe, enabling far-reaching advancements in transportation, communications, energy production, architecture, and agriculture. This powerful legacy, however, is only a brief chapter in the longstanding and ongoing relationship between mankind and metal. Beginning with the working of native metals and the fortuitous discovery of metal smelting, the knowledge and skill of the metallurgist has been essential in the development of civilization. Even today, the development of new alloys which are stronger, lighter, stiffer, and more durable, continues to provide the means for technological advancement into the 21st century.

In this session, we briefly explore the origin of metals and metallic alloys from both scientific and historical perspectives. Topics include:

Both historical and contemporary methods of metal extraction and processing are discussed and detailed examples of specific alloys and applications are given.

The Structure of Cast Metals and the Evolution of Casting Technology

This session offers a brief introduction into the fascinating world of metal casting and the solidification phenomena that occur during the age-old practice of melting and freezing metals and alloys. Along with the technological developments that have led to man’s mastery of these valuable techniques, the physical and chemical structure of cast metals will be explored from the macroscopic scale to the atomic scale. Topics include:

Both fundamental and practical issues will be discussed, with the use of various examples from industry and academia.

Brian Newbury

Emerging Non-Destructive Analysis Methods in Archaeometallurgy: Synchrotron Based X-ray Techniques and Optical Profilometry

In this seminar the problem of non-destructively determining bulk metallurgical data from archaeological and historical metal samples shall be discussed. The synchrotron is a large machine which generates coherent high energy X-rays (10-100 keV) for a wide range of experiments. A group of 40 Islamic and European astrolabes dating from the 13th to 19th century was studied by this completely non-destructive technique. By impinging a high energy (70-80 keV) beam of x-rays capable of transmitting through the brass astrolabes (up to 1cm thick); metallurgical data can be produced from the bulk of the samples without any harm to them. X-ray diffraction, fluorescence, and radiography experiments were performed on the astrolabes and will be discussed. Emphasis will be placed on exactly what one can learn about the forming history, composition, and metallurgy of an archaeological/historical metal sample. Diffraction experiments allowed the composition of the bulk samples as well as mechanical deformation and forming histories to be determined. X-ray fluorescence experiments allowed the near surface (~20 ?m) compositions to be determined, while radiography allowed mapping of the relative thickness. From these experiments and the forming history, it is possible to obtain information about microstructural characteristics and compositions of the astrolabes that no other non-destructive technique could furnish. These data were used to learn more about technical and metalworking techniques used by the astrolabe manufacturers, as well as to determine if any astrolabe parts were later (or modern) replacements. Optical profilometry analysis of surface engraving techniques will also be illustrated, allowing one to study surface markings of a sample in quantitative detail. In addition, historical brass-making technology in the European and Islamic world and brass conservation issues shall be discussed.

Michael Notis

Fabrication, Metallography, and Conservation of the Japanese Sword

This presentation will cover the history, and fabrication processing, of the Japanese sword, starting from smelting of iron by the Tatara process, to forging of the sword component segments, quench hardening, and final polishing. The fabrication context, in terms of cultural and accompanying religious ceremony, will be discussed. The development and changes in sword shape and structure over time, from early history to the medieval period, will be highlighted. Microstructures of swords from selected specimens will be examined in detail and related to fabrication processing.

Because iron is susceptible to rapid corrosion attack, it is often important to understand and interpret the corroded structural remains of iron objects in order to reconstruct and identify the original microstructure, and hence to comprehend the original fabrication processing of iron artifacts. Various examples of remnant microstructures will be shown in order to demonstrate the interaction between corrosion conditions and the complex microstructures in representative iron objects. This will enable a better understanding of proper methods for conservation of such objects.

Corrosion of Archaeological Metals

This talk will present an introductory view of the very complicated and diverse field of corrosion of metallic materials. The presentation will first cover the fundamentals of oxidation of a single metallic species and highlight the kinetics and morphology of growth. We will demonstrate the relationship between Pourbaix Diagrams, predominance diagrams, phase diagrams and a new concept termed "electron number diagrams". We will finally focus on the complicated corrosion processes that take place in typical archaeological iron objects.

Malcolm Parkinson

Use of theoretical mechanics in explaining the properties of materials before the Industrial Revolution

Concentrating on the period from about 1600 to 1750, this lecture examines whether theoretical mechanics was useful to craftsmen in explaining the properties and behavior of materials. Through examining the works of major figures such as Galileo and Newton during the "Scientific Revolution," this study shows how difficult it was to apply the new science of mechanics to materials, both ferrous and non-ferrous.

Matthias Pfaffenbichler

The Conservation of Ferrous Metals

The talk will discuss the conditions which make corrosion of ferrous metals possible. The measures which should be taken to prevent corrosion or to stabilize already corroded iron objects. The problem of restorations and its long term results. The problems which arise with the conservation of objects made out of different materials. Ferrous metals and leather, ferrous metals and wood. The aesthetic aspects of the conservation of ferrous metals.

Surface Treatments and Patinations

The talk will discuss the different decoration technologies like etching, gilding, hammering, polishing, painting and enamel and the problems, which arise when corrosion damages the surface. The talk will discuss the problem of restoration from an aesthetic aspect as well as from the aspect of conservation.

Aldo Reti

Precious Metals Metallurgy and Related Topics

Basic metallurgical aspects of Gold, Silver, Platinum and their alloys will be discussed with the aid of simple phase diagrams, which are useful tools to understand structure/properties relationships; the Karat System for gold will be reviewed, as well as quantitative color descriptions (yellow, red, green and white golds) using the international CIELAB system. Special processing techniques employed for centuries to produce gold leaf and depletion gilding will be explained. Other common forms of gold, known as gold filled and rolled gold plate as well as their manufacturing methods will be discussed.

Sterling Silver properties and processing can be best understood from the silver-copper phase diagram. In addition, the importance of proper deoxidation practices will be pointed out. An interesting old technique to develop surface texture, known as reticulation, will be explained.

There are six elements in the periodic table that make-up the family known as Platinum Group Metals; the most common alloys will be mentioned and important considerations for melting platinum will be discussed.

The presentation will include a review of the Legal Requirements for precious metals in the U.S. and the Hallmarking laws in the U.K.

Yancy Riddle and Robert van Langh

Compositional Analysis of Metal Objects: Comparison of Techniques

When utilized properly, compositional analysis methods provide the researcher and conservative with a variety of data concerning an object’s physical constitution. Many techniques are available for compositional analysis, and as with all techniques, each has its weaknesses and strengths. Understanding some of the fundamental physics behind each technique will enable the user greater confidence with both the utilization and interpretation of results.

In this lecture X-Ray Florescence Spectroscopy (XRF), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction, and Inductive Coupled Plasma (ICP) techniques will be discussed and compared. In addition to providing the student with an understanding of what each technique is actually measuring and how, we will discuss sample preparation, chemical resolution, and spatial resolution, to name a few.

Case studies will include familiar alloys of silver, copper, and steel. Connections will be made between metallurgical phenomena, forming techniques, compositional signatures, and will include a discussion on how these ultimately relate to metal object conservation.

Deborah Schorsch

The Use of X-ray Radiography in the Study of Ancient Works of Art in Metal

X-ray radiography is an imaging technique routinely employed in the laboratory study of works of art, allowing the investigator to view structural and formal features otherwise hidden. In the case of metal objects, radiography is can be useful for determining the method and quality of manufacture (i.e. cast vs. worked, hollow vs. solid, even-walled vs. uneven-walled), location and methods of joining (mechanical vs. metallurgical), the presence of surface decoration obscured by corrosion, to name a few examples. The presence of ancient and modern damages and repairs is also evident in radiographs, making possible a realistic assessment of condition.

Gold and Silver in Moche Culture - Gold and Silver in Egypt in the Time of Tutankhamun

Although disparate in almost every way imaginable, in terms of metalworking tradition the Moche, a people living on the north coast of Peru in from about 100-800 AD, and the ancient Egyptians—at least until the time of the Alexander the Great (r. 336-323 BC)—shared an important and unusual similarity: in both of these cultures silver was more rare than gold. While the study of Moche metalwork focuses primarily on the innovative technology developed to juxtapose gold and silver surfaces in a single object, the Egyptian material is considered in terms of the use of gold and silver together in random, decorative, symbolic, and coloristic pairings on the jewelry found in the tomb of King Tutankhamun.

David Scott

Introduction to Copper Alloys, Casting and Working

Some case studies will be used to illustrate basic principles.

  1. The copper alloys of antiquity. Transition from using native copper to smelted copper. The working and casting of copper alloys. Different types of lost-wax castings and their microstructures.
  2. The copper-tin phase diagram. Brief discussion of surface corrosion and deterioration.

Practical Metallography

Examination of mounted and polished cross-sections of a variety of copper alloy artifacts. The group of 20-25 students will be divided into teams of three or four so that each group will work on a number of copper alloy materials and we will then discuss the microstructures of these different materials. During the class, students will:

  1. Briefly learn how to mount samples.
  2. Grind and polish them and look at the polished state
  3. Etch them and record useful information on the etched surface which we shall then discuss.

Aaron Shugar

Early Copper Production - Reconstructing the pyrotechnological process

The methods used by early metal smiths to produce metallic copper from ore extraction to final casting will be discussed. Discussion will include ideas on the origin of copper smelting and the proposed methods used by these easy smelters. Examples will draw on some of the earliest smelting sites in Israel (~6000 yrs ago) and the first ever found smelting site in Central America.

Reconstruction of a Bronze Age Copper Furnace

A replication of a Bronze Age copper furnace will be used to smelt copper ore and melt metallic copper for open air casting of basic axe blanks. The furnace design and function is based on excavated material from archaeological sites. Participants can get involved and learn how to use bag bellows and run the furnace. It is recommended to attend the ‘Early Copper Production - Reconstructing the pyrotechnological process’ lecture for more details concerning the process.

Rick Sisson

Corrosion: the Environmental Degradation of Materials

When you go out into the world to look for metallic iron or copper (or almost any metal) you do not find the metal you find the ore (i.e. dirt). The metallic form of most metals is not stable at normal atmospheric conditions. The process that transforms metals to the various oxides, hydroxides, carbonates and sulfates is called corrosion. In this presentation these electrochemical processes will be discussed with emphasis on the role of water/humidity/steam as well as the kinetics and thermodynamics of the chemical reactions. The role of various alloying elements on corrosion will also be presented and discussed. The eight forms of corrosion will be highlighted and discussed in terms of several current and historic materials systems.

Robert van Langh

Silver History and Conservation

The field of understanding, authenticating, conserving and preserving a silver object starts with the material and it’s manufacturing technique. Many things can be learned by looking through the eyes of a silversmith or similar craftsman, yet solely the craftsman point of view has been proven insufficient many times. The basis for future accurate understanding and conserving of silver objects should include; the combination of skills from a craftsman, materials scientist, conservation scientist and specialised art historian. Authentication can only take place if the conservator in charge respects these insights and collaborates with the specialisms mentioned.

Authentication

Examples will be given where it seems to be likely that any research undertaken in one specific field, only brought the presumption of dating an object instead of finding proof of it’s origin or technique. One of the emphases during this presentation is put on technological insights.

Examples of pictures with an explanation of the slides will be given where questions will be asked from the participants what they think they are looking at, how we can recognise it and how we can prove this. It should emphasize that especially metals conservation concerns any of the specialised fields and it’s interaction.

Conservation

What are the current possibilities for metals conservation, where have we been focussing on, what is relevant and what not. E.g. who has ever seen that filliform corrosion was a problem with silver? A pragmatic overview of the conservation related problems and possible solutions from a practical point of view.

Outstanding Bronzes

What is important treating outdoor sculpture? Should we cover the sculpture with a lacquer or should we cover it with a wax. No, even better, the best coating is with a lacquer which is covered with a wax. But does this still make sense?

What are the different approaches one can choose from by dealing with outdoor sculpture? Maintenance, in many cases, proves to be a good solution.

How should we construct a pedestal, or when do we refer to a layer as a patina? Some of these questions will be focused on, yet also what we do best if we have a damaged patina. Should we repatinate an object or inpaint the damage. The advantages and disadvantages will be discussed, where ethics and esthetics play a key role, this will be based on a decision making model used in Modern Art Conservation.

George F. Vander Voort and Ronald Biederman

Characterizing Metallic Microstructures

This lecture will introduce the attendees to the fine structure of metals, known as "microstructure," as observed with the reflected light microscope. The microstructures typically obtained after various processes, such as casting, hot working, cold working and heat treatment, as well as some processes that affect the surface, will be illustrated for a variety of metals and alloys commonly used. As much as possible, the illustrations will be obtained from historically significant objects. The lecture will introduce the attendees to the terms used to describe microstructures in common alloy systems. Procedures used to identify specific phases and constituents will be discussed.

Metallography and Microscopy

This lecture will introduce the attendees to the science of metallography, the characterization of the microstructure of metallic (and nonmetallic) materials using the reflected light microscope. Metallographic specimen preparation must be properly performed in order to reveal the true microstructure. Inadequate preparation, or incorrect preparation procedures will produce artifact structures that may be interpreted in place of the true microstructure yielding errors. The process involves the following steps: sampling, sectioning, encapsulation ("mounting"), grinding, polishing, etching, examination and documentation. Basic aspects of the proper use of the light microscope will be presented. Demonstrations of the preparation of historical objects will be performed using the latest techniques. The use of color metallographic techniques will be described. Students will receive a CD of the book, Buehler’s Guide to Materials Preparation which covers these topics, as well as several others.

Jeffrey Wadsworth

Damascus Steels, Welded Damascus Steels, the Iron Plate Found at the Great Pyramid of Giza, and the Carbon Dating of Ancient Iron and Steel Artifacts

In the 1970s, my colleagues and I began developing a class of ultrahigh-carbon steels for their superplastic characteristics, with an eye to potential commercial applications. We became aware of striking compositional similarities between these modern steels and the ancient steels of Damascus. This observation led us to revisit the history and metallurgy of Damascus steels and related materials, which can be traced back to the time of Alexander the Great (323 BCE). We also designed and manufactured laminated composites containing various levels of carbon, and our studies showed that these composites have unique toughness characteristics and are similar to a range of laminated materials of historical interest, including Merovingian (Viking) blades, Japanese swords, Indonesian krises, and welded Damascus shotgun barrels. A laminated steel composite of particular interest was found in the South Channel of the Great Pyramid at Gizeh in 1837. The plate has been the source of considerable controversy; if it is truly contemporaneous with the building of the pyramids, then it raises significant questions regarding the start of the Iron Age. This issue inspired us to start a program on radiocarbon dating to directly determine the age of ancient irons and steels, with the hope of directly dating the Gizeh plate. In this lecture, I will describe our attempts to reproduce the distinctive surface patterns that famously characterized Damascus steel, discuss our experimental and theoretical work on laminated composites, review the details of the discovery of the Gizeh plate, and present our work on carbon dating of ancient steels.

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Last modified: Jul 17, 2007, 11:34 EDT

Cristina Bauer, Program Coordinator
Higgins Armory Museum, 100 Barber Avenue, Worcester, MA 01606-2444 USA
508-853-6015 x23 - Fax: 508-852-7697 - cbauer@higgins.org