Mathematics and Science in Schools in Sub-Saharan Africa

MATERIAL SCIENCE Introduction to METALS

All the elemnets in yellow are classified as metals.

Metals have the ability to help predict the future.

World Stability Stock Market The price of gold reflects the stability of global relationships. The price of copper reflects the strength of the global economy.

Atomic Structure To understand the behavior of metals, one must look at their atomic structure. Lithium.

Metallic Bonding “Sea of Electrons” The bonding that exists between the atoms found in a metal is often referred to “sea of electrons”. “Sea of Electrons”

Properties of Metals Metals are strong.

Metals have a lustrous look when polished. Properties of Metals Metals have a lustrous look when polished.

Properties of Metals Metals are flexible.

Properties of Metals Metals are malleable.

Metals expand when heated. Properties of Metals Metals expand when heated.

Thermal Expansion

Metals have a very high conductivity rate of heat and electricity. Properties of Metals Metals have a very high conductivity rate of heat and electricity.

Commercial Applications Copper Aluminum Cast Iron Copper pot, cast iron skillet, aluminum pots & stainless steel. Steel Cookware

Medical Applications Ohio University scientists Hugh Richardson and Sasha Govorov. Using laser light, Ohio University scientists uses gold nanoparticles to kill cancer tumors.

Medical Applications When stimulated with the right frequency of laser light, a small collection of metal nanoparticles, such as gold, can heat an area up to 1,000 times its size, according to Ohio University scientists Hugh Richardson and Sasha Govorov. Metal nanoparticles, such as gold, can heat an area up to 1,000 times its size.

Medical Applications Partial view of a gold nanosphere (shown), magnified by a factor of one billion, as seen through an electron microscope. The darker ring shows the "wall" of the nanosphere, while the lighter area to the right of the ring shows the interior region of the shell. The hollow particles can be made in sizes ranging from 20 to 70 nanometers in diameter, which is an ideal range for biological applications that require particles to be incorporated into living cells. researchers attached a short peptide to the nanospheres that enabled the particles to bind to tumor cells. After injecting the nanospheres into mice with melanoma, the researchers irradiated the animals' tumors with near-infrared light from a laser, heating the gold nanospheres and selectively killing the cancer cells to which the particles were bound. A short peptide is attached to the nanospheres of gold that enabled them to bind to tumor cells.

Medical Applications Partial view of a gold nanosphere (shown), magnified by a factor of one billion, as seen through an electron microscope. The darker ring shows the " Using a near-infrared light from a laser, heat the gold nanospheres and selectively kill the cancer cells to which the particles were bound.

Electrical Applications

Certain metals can be magnetic. Properties of Metals Certain metals can be magnetic.

Non-Magnetic Metals

Magnetic Metals

Metals are crystalline in structure. Properties of Metals Metals are crystalline in structure.

Crystal Structures of Metals Aluminum FCC Cadmium HCP Chromium BCC Cobalt HCP Copper FCC Gold FCC Iron BCC Lead FCC Magnesium HCP Nickel FCC Niobium BCC Platinum FCC Polonium Cubic Silver FCC Titanium HCP Vanadium BCC Zinc HCP Zirconium HCP

Disadvantages of Metals Metals corrode!

Unit #1: History of Metals

Metallurgy is one of the oldest applied sciences. The history of metals is closely linked to that of coins and gemstones.

Metallurgy As early as 3400 B.C., at the beginning of the historical period, the Egyptians had an intimate knowledge of gold, copper ores and of processes of extracting metals.

Metals were also known to the Mesopotamians, Greeks and the Romans. Metallurgy Metals were also known to the Mesopotamians, Greeks and the Romans.

Native Metals Copper Gold Mercury Silver

Native Metals Iron

Native iron is easily distinguishable because it contains 6-8% nickel. Iron was available to the ancients in small amounts from meteors. Shown here is an imperial coin of Emesa, in Syria with a conic 'Aerolith' being carried on a quadriga or four-horse chariot Native iron is easily distinguishable because it contains 6-8% nickel.

The first metal to be used was copper. Copper Age (~4000 B.C.) The first metal to be used was copper.

The first tools, implements & weapons were made from copper. Copper Age (~4000 B.C.) The first tools, implements & weapons were made from copper.

Copper Age (~4000 B.C.) The oldest known casting in existence, a pure copper frog, was cast in Mesopotamia.

Bronze was the first alloy used. Bronze Age (~3000 B.C.) Bronze was the first alloy used. Bronze = Copper & 5-10% Tin

Bronze Age (~3000 B.C.) New discoveries near Ban Chiang, Thailand, indicate that bronze technology was maybe known there as early as 4500 BC!

Iron smelting began in Egypt. Iron Age (~2000 B.C.) Iron smelting began in Egypt.

Process of Iron Smelting A mixture of iron and oxide impurities is heated to about 1,500°C. Molten iron is drawn off on one side, and slag (waste) on the other.

Iron Age (~2000 B.C.) Iron weapons revolutionized warfare and iron implements did the same for farming.

Iron Pillar ~ 400A.D. This iron pillar dating to 400 A.D., remains standing today in Delhi, India. Corrosion to the pillar has been minimal a skill lost to current ironworkers.

Chinese were the first in the production of cast iron.

Molten iron is "cast" into forms made of sand. Cast Iron (~800) Molten iron is "cast" into forms made of sand.

Steel (~500)

Wood was needed as timber and it takes too much wood so smelt iron. How To Smelt Iron? Wood Wood was needed as timber and it takes too much wood so smelt iron.

How To Smelt Iron? Coal Although cheap and plentiful, coal contained sulphur that made the iron too brittle to be of any use.

In 1709, Abraham Darby finally succeeded in smelting iron with coke.

Steel becomes the world’s most used material. 1750 Steel becomes the world’s most used material.

Steel Production Today Step 1: Fe2O3(s) + 3CO(g) = 2Fe(l) + 3CO2(g)

Steel Production Today Step 2: Molten iron is mixed with carbon & other elements.

Isolated Pure Aluminum 1850 Isolated Pure Aluminum Charles Martin Hall, "American chemist, who discovered an inexpensive method for the isolation of pure aluminum from its compounds. The same electrolytic process was discovered concurrently by the French chemist Paul L.T. Heroult and is therefore known as the Hall-Heroult process. It became the basis for the aluminum industries both in the United States and in Europe. Charles Martin Hall

1900 Aircrafts move from fabric to high strength aluminum alloys.

Specialty Alloys (1935-1955)

Human Body Parts (1955-present) High quality alloys of titanium & cobalt.

Super Alloys (1970-Present) Since they can sustain high temperatures, super alloys were developed for jet engines.

Transparent Aluminum (2010) A ceramic research lab in Dresden, Germany, has developed transparent Alumina by subjecting fine-grained aluminum to a whopping 1200 degrees Celsius ...the result of which is amazingly light but three times tougher than hardened steel of the same thickness, and it's see-through. Fine grained aluminum is heated to 1200°C! 3X tougher than steel & it’s see-through!

Metamaterials (2015) Materials designed that use light to manipulate its mechanical properties.

The top is a bilayer gold/silicon nitride membrane containing an array of cross-shaped nanoantennas etched into the gold layer. The bottom is a metal reflector that is separated from the gold/silicon nitride bilayer by a three-micron-wide air gap.

The device can potentially be used as a new frequency reference to accurately keep time in GPS, computers, wristwatches and other devices.

New Fuel Cell Catalyst (2016)

Haotian Wang and his Stanford colleagues developed a new way to fine-tune platinum catalysts in fuel cells and other clean-energy technologies. A nanosize squeeze can significantly boost the performance of platinum catalysts that help generate energy in fuel cell.