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The Uses of Gold
Gold's superior electrical conductivity, its malleability, and its resistance to corrosion have made it vital to the manufacture of components used in a wide range of electronic products and equipment, including computers, telephones, cellular phones, and home appliances.
Gold has extraordinarily high reflective powers that are relied upon in the shielding that protects spacecrafts and satellites from solar radiation and in industrial and medical lasers that use gold-coated reflectors to focus light energy. And because gold is biologically inactive, it has become a vital tool for medical research and is even used in the direct treatment of arthritis and other intractable diseases.
COMPUTERS/SEMICONDUCTORS
Millions of computers are manufactured worldwide each year and gold plays an active role in their many components. The most important use of gold is as a fine wire that connects circuits to the semiconductors, or the "brains" of the computer. This "bonding wire" is specially refined (up to "five nines" or 99.999-percent pure gold) and has an average diameter of one hundredth of a millimeter - smaller than the diameter of a human hair. Gold is also used as a paste with which a circuit is printed on a ceramic base to produce a printed circuit board. In other areas, each key on the computer keyboard strikes gold circuits that relay the data to the microprocessor. Computer games also use printed circuit boards that have gold circuitry to connect the logic units in the game package. Computer peripherals, where there is frequent plugging and unplugging, use gold-coated contacts to assure consistently clean, corrosion-free contacts and reliable signals. Gold is essential in computer circuitry because of its electrical conductivity and because it does not degrade over time.
POWERCHAIRS
Computerized wheelchairs, called powerchairs, allow disabled patients further control over their movements and a renewed sense of independence. At the heart of the computerized controls is a tiny, but powerful, Motorola microprocessor connected to the wheelchair's controls by gold wire and gold-coated connector pads. Gold is used in this application because of its high electrical conductivity and its resistance to corrosion. The powerchair, which is exposed to many climates and temperatures, could not operate properly without its gold corrosion-resistant components.
SPACECRAFT
To protect the onboard computers in the Galileo space probe from short circuiting as a result of heavy bombardment, NASA developed a Heavy Ion Counter (HIC). The HIC contains silicon wafers with gold electrodes that detect the heavy ions as they penetrate the wafers. Use of the HIC allows NASA engineers to monitor the functioning of onboard computers and make adjustments when necessary.
The Pathfinder "robotic geologist" that took close-up color pictures of rocks and soil on Mars and analyzed the planet's chemical makeup, relied on sophisticated electronics to direct its landing and movement. In addition, intricate gold circuitry enabled sophisticated computer technology to transmit the Pathfinder's information back to Earth.
TELEPHONES
Behind the protective cover of every telephone mouthpiece is a miniature transmitter that contains gold in one of its central components, the diaphragm. A gold-plated dome in the diaphragm works with the other mouthpiece components to transcribe voice vibrations into an electrical current. Gold is used in this application because of its permanence, particularly in public phones that are exposed to outdoor weather conditions.
TELEPHONE WALL JACKS
Because gold conveys a superior signal, and does not corrode or tarnish, it is used to coat billions of contacts for phone jacks and connecting cords throughout our nationwide telephone system. The phone wall jacks are goldcoated to assure the customer of the convenience of moving the phone from one wall jack to another while maintaining clear static-free conversation.
TVs AND VCRs
The microcircuitry in televisions is composed of fine lines of gold circuits connected by hair-thin gold wires to the micro-electronic circuit chips that process broadcast signals into a TV picture. Cables connecting television sets to videocassette recorders are goldcoated to assure clear relay of the television signal.
MEDICINE AND HEALTH
Gold is valuable to modern medicine because it is non-toxic and biologically benign, one of the most efficient conductors of electricity, and its density enables it to be seen under electron microscopes. And although gold is virtually indestructible, it is a soft metal, easy to work with, shape, flatten or draw out into microscopic strands.
DENTISTRY
Most gold used in dentistry is in the form of alloys, which are mixtures of gold and other metals, such as platinum, palladium, silver, copper and zinc. Gold is non-toxic and biologically inert, which makes gold ideal for use in dental procedures. It is easy for the dentist to manipulate, but strong, stiff, durable and tough — it never wears or tarnishes. It is also very resistant to chemical attack and does not corrode.
EYE SURGERY
Accidents, disease or surgery may cause a condition called Lagophthalmos, which is the inability to close the eyelids fully. In order to keep the eyelids moist, doctors previously resorted to sewing the eyelid half shut, but a new gold eyelid implant is now the current form of treatment. These gold "eyelid load implants" are surgically inserted into the upper lid and allows the eye to blink normally. The muscle that opens the eyelid works to hold the eyelid open; then, when the muscle relaxes, gravity exerted on the gold causes the eyelid to drop. Gold is the best choice for this device as it does not corrode and will not react with tears.
LASERS
One of the most promising new areas of medical treatment is in the use of ion lasers, the interior surfaces of which are coated with gold to control the focus of the beam. In one development, gold vapor lasers create a high intensity red light with the required wavelength to seek out and selectively destroy cancerous cells without harming healthy neighboring cells. A new lightweight laser, designed by the military and using gold plated contacts, enables medics to seal battlefield wounds in the field, thereby reducing blood loss and improving survival chances for the seriously wounded. In hospitals, this new design will allow lasers to be brought to critically injured emergency patients without moving them, saving minutes and lives.
Surgeons use gold instruments to clear clogged coronary arteries. Injection of microscopic gold pellets helps retard prostate cancer in men. Some forms of cancer are treated with colloidal gold. Lasers with gold-coated parts literally give new life to patients with once-inoperable heart conditions and tumors.
These gold-reliant lasers are revolutionizing medicine - from pinpoint destruction of cancerous cells to rapid emergency surgical procedures, to delicate surgery on eyes and brain tissue that was previously not possible. Most recently, gold-coated lasers are being used to rejuvenate skin tissue damaged by burns and injuries, while leaving the surrounding healthy tissue unaffected. Because of its inert and benign nature, gold can be used inside the human body without fear of corrosion or harmful physical reactions in most cases.
