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Glasses Refractories Abrasives Cements Products Ceramics CERAMIC MATERIALS I Asst. Prof. Dr. Ayşe KALEMTAŞ [email protected], [email protected], Phone: 211 19 17 Metallurgical and Materials Engineering Department INTRODUCTION MATERIALS CERAMIC METAL POLYMER COMPOSITE D CLAY ADVANCED GLASSES REFRACTORIES ABRASIVES CEMENTS PRODUCTS CERAMICS Glass- Glasses ceramics Asst. Prof. Dr. Ayşe KALEMTAŞ INTRODUCTION HISTORY DEFINITION PROPERTIES APPLICATIONS Asst. Prof. Dr. Ayşe KALEMTAŞ INTRODUCTION Four of the major technological achievements in glass which have had the most profound impact on mankind. Glass window – which enables sunlight to come into dwelling unit . Lenses – opthamics for improved vision, microscope, telescope optics . Light bulb envelope - lighting . Semiconducting glasses – for computer memory, solar cell, photocopiers Asst. Prof. Dr. Ayşe KALEMTAŞ Well Known Glass Products www.whitersstreetglass.com.au Glass splashbacks http://www.wickedreport.com Hirom Glass Violin is a product of Hario www.toxel.com Glass Co. Ltd., Japan. And also, The Glass Bathtub world’s first hand made glass violin. http://freshome.com http://worlds-interior-design.blogspot.com Superdurable tempered glass Wall-to-wall glass windows Asst. Prof. Dr. Ayşe KALEMTAŞ Well Known Glass Products Asst. Prof. Dr. Ayşe KALEMTAŞ Well Known Glass Products Tempered glass table http://freshome.com http://www.ifjk.org www.aarticommercial.com/prod www.tripadvisor.com ucts.php Heat resistant Glass sink cabinets in the bathroom Laminated Windscreen Glass glass door Asst. Prof. Dr. Ayşe KALEMTAŞ Well Known Glass Products http://www.wolfard.com Classic Wolfard Oil Lamp Heat resistant glass lid Heat resistant glassware Tempered Glass (microwave safe) Cutting Board Asst. Prof. Dr. Ayşe KALEMTAŞ INTRODUCTION Any material that exhibits only a short-range order of atoms or ions is an amorphous material; that is, a noncrystalline one. In general, most materials want to form periodic arrangements since this configuration maximizes the thermodynamic stability of the material. Amorphous materials tend to form when, for one reason or other, the kinetics of the process by which the material was made did not allow for the formation of periodic arrangements. Glasses, which typically form in ceramic and polymer systems, are good examples of amorphous materials. Asst. Prof. Dr. Ayşe KALEMTAŞ INTRODUCTION Definitions of Glass The origin of the word glass is the late Latin term glæsum used to refer to a lustrous and transparent or translucent body. Glassy substances are also called vitreous, originating from the word vitrum, again denoting a clear, transparent body. Although glass became a popular commodity in the growth of civilization, perhaps because of its transparency, luster (or shine), and durability, the current understanding of glass no longer requires any of these characteristics to distinguish it from other substances. Glass can be inorganic (non-carbon based) as well as organic (carbon- based), and fusion is not the only method to make a glass. Thus, the old ASTM definition that glass is an inorganic product of fusion which has been cooled to a rigid condition without crystallizing is not appropriate. Handbook of Ceramics, Glasses, and Diamonds, Charles A. Harper Editor-in-Chief, Chapter:5, Inorganic Glasses- Structure, Composition and Properties, Arun K.Varshneya and Thomas P. Seward III, McGRAW-HILL Asst. Prof. Dr. Ayşe KALEMTAŞ INTRODUCTION Methods of Making Inorganic Glasses The most common method for making glass is to: . Fuse various raw materials in appropriate proportions together with the application of heat, . Gather and form into useful products, . Cool subsequently at a rate fast enough to avoid distortion of the shape yet slow enough to avoid cracking. Inorganic glasses may also be obtained by . Hydrolyzing an alcoholic solution of an organometallic compound, . Stirring the hydrolyzed product to allow rapid chelation to a gel state, . Drying the gel mass to drive off the organics, . Sintering at an elevated temperature to obtain a compact. This method, called the sol-gel route to glassmaking, is often used to deposit thin films such as antiref lection coatings. The sol-gel process of making a glass avoids the normally high temperatures employed for the fusion of glass. Chemical vapor deposition is yet another technique which completely avoids fusion of constituent materials. Asst. Prof. Dr. Ayşe KALEMTAŞ INTRODUCTION The earliest written records of glass making are some famous clay tablets, dating from around 650 BC, from the library of Assur-bani-pal, but these are incompletely understood because we have no dictionary to explain the technical terms. Many centuries passed before written accounts of glass making contained any useful insight besides recipes to be followed by rote. The earliest development in glass making of which we have a reasonably documented description seems to be the invention of glass of lead by Ravenscroft around 1673-1676. Asst. Prof. Dr. Ayşe KALEMTAŞ Glass from Nature Natural Glass Probably as early as 75,000 B.C.E., long before human beings had learned how to make glass, they had used natural glass to fashion knives, arrowheads, and other useful articles. The most common natural glass is obsidian, formed when the heat of volcanoes melts rocks such as granite, which then become glassy upon cooling. Other natural glasses are pumice, a glassy foam produced from lava; fulgurites, glass tubes formed by lightning striking sand or sandy soil; and tektites, lumps or beads of glass probably formed during http://www.chemistryexplained.com/Ge-Hy/Glass.html#ixzz3G6sDTQBl Asst. Prof. Dr. Ayşe KALEMTAŞ Glass from Nature Obsidian The first glass, used by early man is obsidian. Ryolite lava flows from volcanoes and swiftly cools, impeding the formation of crystals and creating absidian glass. This glass has an irregular structure and, therefore, fractured into smooth curved shapes with finer edges. Around the world, many early cultures discovered these properties and utilized this glass in weapons, tools, and decoration. Uses of Obsidian as a Cutting Tool The conchoidal fracture of obsidian causes it to break into pieces with curved surfaces. This type of fracturing can produce rock fragments with very sharp edges. These sharp fragments may have prompted the first use of obsidian by people. The first use of obsidian by people probably occurred when a sharp piece of obsdian was used as a cutting tool. People then discovered how to skillfully break the obsidian to produce cutting tools in a variety of shapes. Obsidian was used to make knives, arrow heads, spear points, scrapers and many other weapons and tools. Once these discoveries were made, obsidian quickly became the raw material of preference for producing almost any sharp object. The easy-to-recognize rock became one of the first targets of organized "mining". It is probably a safe bet that all natural obsidian outcrops that are known today were discovered and utilized by ancient people. http://geology.com/rocks/obsidian.shtml Asst. Prof. Dr. Ayşe KALEMTAŞ Glass from Nature Obsidian is a popular jewelry stone. A thin piece of obsidian is often used as a "backing" material for opal doublets and triplets. The black obsidian adds stability to the opal and provides a dark background color that contrasts with the opal's fire. Mahogany obsidian and snowflake obsidian cabochons set in a sterling silver pendants. Freshly broken pieces of obsidian have a very high luster. Ancient people noticed that they could see a reflection in obsidian and used it as a mirror. http://geology.com/rocks/obsidian.shtml Asst. Prof. Dr. Ayşe KALEMTAŞ Glass from Nature Obsidian in Modern Surgery Although using a rock as a cutting tool might sound like "stone age equipment", obsidian continues to play an important role in modern surgery. Obsidian can be used to produce a cutting edge that is thinner and sharper than the best surgical steel. Today, thin blades of obsidian are placed in surgical scalpels used for some of the most precise surgery. In controlled studies, the performance of obsidian blades was equal to or superior to the performance of surgical steel. http://geology.com/rocks/obsidian.shtml Asst. Prof. Dr. Ayşe KALEMTAŞ Glass from Nature magma fulgurite obsidian tektites Asst. Prof. Dr. Ayşe KALEMTAŞ Manmade (Synthetic) Glass When, where, or how human beings discovered how to make glass is not known. Very small dark-colored beads of glass have been dated back to 4000 B.C.E. These may well have been by-products of copper smelting or pottery glazing. By 2500 B.C.E. small pieces of true synthetic glass appeared in areas such as Mesopotamia, but an actual glass industry did not appear until about 1500 B.C.E. in Egypt. By this time various small vases, cosmetic jars, and jewelry items made of glass had begun to appear. All the ancient glasses were based on silica (sand), modified with considerable amounts of various metal oxides, mainly soda (Na2O) and lime (CaO). This is still the most common glass being used today. It is known as soda lime glass. However, the ancient glass was usually colored and opaque due to the presence of various impurities, whereas most modern glass has the useful property of transparency. http://www.chemistryexplained.com/Ge-Hy/Glass.html#ixzz3G6so8r7V Asst. Prof. Dr. Ayşe KALEMTAŞ GLASS - 4000: Jewel in molted glass -(Phoenicia) Asst. Prof. Dr. Ayşe KALEMTAŞ GLASS -1500: Vases and vessels (Egypt) Asst. Prof. Dr. Ayşe KALEMTAŞ GLASS Egyptians Romans Middle Ages • First people to • By Roman times • Main achievements realize what could glass being blown were colored glass be done with glass and molded, cut and windows. when it is hot and engraved, and plastic. painted. • Made vessels for cosmetics and perfumes by forming molten glass around a shaped core. Asst. Prof. Dr. Ayşe KALEMTAŞ INTRODUCTION A glass is a solid that possesses no long-range atomic order and which undergoes the glass transformation from solid to supercooled liquid on heating. Crystalline materials have a definite structure, whereas amorphous ones do not, and therefore only rather general statements can be made about a material which, when hot, is ductile but when cold is brittle, and fractures if there is a sudden change of temperature.
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