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Monetary Metal
Until the late 19th century most nations were on a silver standard with silver coins forming the main circulating currency - silver being in greater supply and of less value than gold, thus being more practical for everyday payments. As gold became more plentiful, however, silver was slowly replaced although it is still used in some circulating coins as well as in bullion coins for investors. In the U.S., silver is used only in bullion, commemorative and proof coins. Mexico is the only country currently using silver in it's circulating coinage. During the past decade, the United States, Canada and Mexico began issuing pure silver bullion coins with nominal face values sold at a small premium over their bullion value (not their face value).
In 1982, Mexico began minting a 999-fine (99.9% pure) silver Libertad ranging in weight from 1/20 oz. to 5 ounces; over 20 million coins have been sold. The U.S. Mint issues a 999-fine Silver Eagle (a one ounce bullion coin with a face value of $1) bullion coin; over 100 million have been sold since 1986. The Royal Canadian Mint issues a 5 dollar 9999-fine silver bullion coin, the silver Maple Leaf; over 11.8 million have been sold since 1988. Australia has issued a 5-dollar, 1 ounce .999 fine silver bullion coin, the Kookaburra; over 8 million have been sold since 1990.
Photography
Although a wide variety of other technology is available, silver-based photography will retain its pre-eminence due to its superior definition and low cost. From it's very outset, silver halide has been the material that records what is to be seen in the photograph. As little as 4 photons of light activate silver halides which amplify that incident light by a factor of one billion times. In today's photography, silver halides are coupled with dyes that bring the color of the world around us into permanent record. An estimated 196 million troy ounces of silver were used worldwide in 2003 for photographic purpose.
William Conrad Roentgen's discovery of x-rays in 1895, led to his discovery that they activate silver halide crystals. This revolutionized medical diagnosis. Radiographic use of silver worldwide consumed 90 million troy ounces in 2002.
Today, X-ray inspection is also essential to ensure integrity of metallic castings from small truck axles to the huge aircraft-carrier steam valves used to propel airplanes from a flight deck. Of all the inspection techniques, it is the image on a silver halide x-ray film that provides the clearest indication of flaws deep within metallic components.
Non-destructive x-ray testing is a critical element in product approval, ensuring the safety of all types of transportation conveyances from ships to aircraft. It remains the most effective way to reveal flaws in metallic components. The continuing requirement for the specially-sensitized silver halide film in which metallic flaws leave their identifiable signatures that can be compared with standard photographs will assure silver's continued preeminence for this essential quality control technique.
Mirrors and Other Coatings
Everyone is accustomed to silvered mirrors. What is new is invisible silver, a transparent coating of silver on double pane thermal windows. This coating not only rejects the hot summer sun, but also reflects inward internal house heat. A new double layer of silver on glass marketed as "low E squared" is sweeping the window market as it reflects away almost 95% of the hot rays of the sun, creating a new level of household energy savings. Over 250 million square feet of silver- coated glass is used for domestic windows in the U.S. yearly and much more for silver coated polyester sheet for retrofitting windows.
One out of every seven pairs of prescription eyeglasses sold in the U.S. incorporates silver. Silver halide crystals, melted into glass can change the light transmission from 96% to 22% in less than 60 seconds and block at least 97% of the sun's ultraviolet rays. The change is endlessly reversible.
Medicine
Dr. Robert O. Becker, a researching orthopedic medical doctor, was one of the early pioneers of silver experimentation for medical applications. Dr. Becker re-discovered the broad-spectrum antibacterial properties of silver, and clinically demonstrated both the tissue healing properties of silver ions and the antimicrobial properties of silver. By surgically inserting silver electrodes, and applying a small amount of electrical current, Dr. Becker proved his famous "current of injury" theory and demonstrated the incredible healing properties of silver by successfully mending infected non-union bone fractures.
Dr. Becker's in-vitro experimentation testing silver ions against cancer cells and subsequent observations documenting beneficial morphogenic changes to living cells has paved the way to the eventual "discovery" of advanced medical technologies involving silver iontophoresis and possibly even human regeneration.
Water Purification
Silver ions have been used to purify drinking water and swimming pool water for generations. New research into silver compounds is providing physicians with powerful, clinically effective treatments against which bacteria cannot develop resistance.
An increasing trend is the millions of on-the-counter and under-the-counter water purifiers that are sold each year in the United States to rid drinking water of bacteria, chlorine, trihalomethanes, lead, particulates, and odor. Here silver is used to prevent the build-up of bacteria and algae in the filters. Of the billions of dollars spent yearly in the U.S. for drinking water purification systems, over half make advantageous use of the bactericidal properties of silver. New research has shown that the catalytic action of silver, in concert with oxygen, provides a powerful sanitizer, virtually eliminating the need for the use of corrosive chlorine.
Jewellery and Silverware
Sterling silver contains 92.5 percent silver. It is commonly alloyed with gold or copper for manufacture of stunning jewellery and silverware. Silver can be buffed to a higher polish than any other metal, a quality highlighted in mirrors and reflective coatings on glass, cellophane and metals. Silver's superior ductility and reflective luster make it a better metal for jewelry than the more brittle and duller gray finish of platinum -- it is also much less expensive.
Solar Energy
Silver paste is used in 90 percent of all crystalline silicon photovoltaic cells, which are the most common solar cell, according to the Photovoltaic Technology Division of the U.S. Department of Energy. And all silicon cells used in space to power satellites use silver in the form of evaporated metal to make the electrical contact.
The electricity generated by photovoltaic cells is highly reliable. As soon as sunlight strikes, power begins to flow. Sunlight striking silicon cells generates electrons, which the silver conductors collect to become a useful electric current. The conductive silver, which also enhances reflection of the sunlight, is applied in the form of a glass paste with a minimum of 90 percent silver along the top and across the bottom of the silicon crystal. When fired, the silver forms a complete circuit collecting solar energy and conducting it to the power supply line. A group of roofing-tile solar cells can generate sufficient power to provide a house and also fill batteries to supply power after dark.
Silver plays yet another role in the collection of solar energy: efficient reflection of solar heat. Silver is the best reflector of thermal energy (after gold).
Electronics
Every time a home owner turns on a microwave oven, dishwasher, clothes washer, or television set, the action activates a switch with silver contacts that completes the required electrical circuit.
The majority of the keyboards of desk-top and lap-top computers use silver membrane switches. These are found behind the buttons of control panels for cable television, telephones, microwave ovens, learning toys like touch and tell or speak and spell, and the keyboards of typewriters and computers. The low-current capacity of the membrane switch matches the low electrical current used for digital electronics. In an office environment, membrane switches are normally rated for a life of 20 million cycles. Typically, the membrane switch is made of a conductive ink of silver flakes in a polyester binder with carbon. This thick film is then silk-screened in an electrical circuit pattern onto each of two Mylar sheets. The two surface patterns of silver face each other close enough so that gentle touch by a finger will make the electrical contact. A latching transistor circuit is simultaneously activated to keep the circuit closed after the membrane is released.
Giant magnetoresistance is a newly discovered magnetic property of multiple layered silver/nickel-iron alloy films, each about a millionth of an inch thick. These films are being exploited by computer hard drive manufacturers. The films are potential candidates for the next generation of read-out heads for personal computer storage systems.
Electrical
Silver is the best electrical conductor of all metals and is hence used in many electrical applications, particularly in conductors, switches, contacts and fuses. Contacts, a junction between two conductors that can be separated and through which a current can flow, account for the largest proportion of electrical demand.
From the very beginning of electricity, silver has been the metal of choice for switch contacts because of its low contact resistance, high thermal conductivity, mechanical wear resistance, chemical stability (it does not corrode), low polymer formation (the build-up of an insulating carbon-polymer film over the contact as a consequence of arcing), and cost-effectiveness (it provides the longest functional life).
Over 50 categories of electrical components incorporating silver as the contact material are listed by The National Electrical Manufacturers Association, Washington, D.C. These range from silver thick films that are used to make membrane switches which carry 5 volts or less for electronic systems, to large circuit breaker contacts required to interrupt or close the circuits of 75,000-volt power distribution lines.
The use of silver for motor control switches is universal. In the home, wall switches, timing devices, thermostats, sump pumps, and virtually all electrical appliances use silver contacts. A typical washing machine requires 16 silver contacts to control its electric motor, pump, and gear clutch. A fully-equipped automobile may have over 40 silver-tipped switches to start the engine, activate power steering, brakes, windows, mirrors, locks, and other electrical accessories.
Catalysts
A substance that increases the rate of a chemical reaction, without being consumed or produced by the reaction, is known as Catalyst.
Since 1908, it has been known that silver greatly increases the efficiency of the production of formaldehyde from methyl (wood) alcohol. Here silver catalyses the oxidation of an alcohol into an aldehyde called formaldehyde, which is one of the most important industrial and research chemicals. It is an essential building block for a class of plastics with an estimated world production exceeding 15-million tons per year which includes adhesives, laminating resins for construction plywood and particle board, finishes for paper and electronic equipment textiles, surface coatings that resist heat and scratches, dinnerware and buttons, casings for appliances, handles and knobs, packaging materials, automotive parts, thermal and electrical insulating materials, toys, and the list goes on.
Brazing & Soldering
Silver (hard) Soldering or Brazing is a very versatile means of making joints by using a fusible alloy as a filler material between similar or dissimilar parent materials. Temperatures above 620°C are applied, usually by handheld flame torch or another heating device, eg induction or electrical heater/furnace, to melt the filler material into a capillary gap between the parent materials and create a suitable bond. Such joints are invariably leak proof, will withstand vibration, tensile and torsional loading, and maintain integrity at both sub-zero and elevated temperatures. When well selected and applied, they can also resist attack to a wide range of corrosive environments.
Bearings
Precision Thin Section Bearings are now available through National Precision Bearing. SilverThin bearings are produced in the USA. Standard Bearings from 1-inch bore to 35-inch bore, with Specials upon request. Angular, radial and four-point contact types stocked. If your requirements call for Precision Thin Section Bearings or large diameter Thin Section Torque Tube bearings, think SilverThin bearings.
It was a layer of silver on main shaft bearings of the 9,000 horsepower reciprocating engines of the World War II Superfortress that resolved the unacceptable failure rate of its giant engines. Silver, with its superior fatigue resistance, lubricity, corrosion resistance, and thermal conductivity came to the rescue.
Today's commercial and military jet engines deliver 35,000 to 100,000 pound thrusts under high-temperature conditions. Despite the far higher power and a far more rigorous internal environment, silver coated bearings continue to provide the superior performance and critical margin of safety for today's jet engines.
The use of silver in high-performance bearings provides the wide margin of safety demanded by Pratt & Whitney, General Electric, Rolls Royce, and all other producers of jet engines that power modern aircraft.
Batteries
The Silver Polymer Battery utilizes divalent silver oxide to achieve very high energy and power, yielding up to twice the energy to volume of current lithium ion and lithium polymer batteries.
The gravimetric storage density for Silver Polymer Batteries is about the same as lithium ion batteries, but the volumetric energy density is much greater, because the materials are far denser than those in lithium batteries. Their standard cells can be recharged only about 100 times, which doesn't sound all that wonderful at all, but supposedly compares well with lead acid. A 12V 15Ah battery made from 8 silver polymer cells would weigh 1.4kg - supposedly a quarter of what a similar spec lead acid battery weighs. However, the Silver Polymer Battery has "only" 80 amps peak, probably costs several tens as times as much, and has very fussy recharging requirements.
The Silver Polymer Battery has the following advantages:
- Up to ten times the energy to weight ratio of current lead acid designs and up to four times the energy to weight ratio of NiMH designs.
- No memory and low self discharge.
- Tunable price/performance from low cost to maximum performance preference.
- Dramatically safer than large lithium batteries which are now subject to severe transportation limitations.
*Information provided by silverstrategies.com
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