Surprising Zinc

With  many  thousands   of    patents   and literally

millions  of  products to  its credit ,  zinc  played  a

 supporting  role in many of the  major  inventions

  of the  20th Century

When asked to describe how zinc is used, most people name vitamins, or perhaps sun creams. Some may add galvanizing and die casting to the list, but few are aware of the extent to which zinc, and zinc-based technology,  contributes to  our daily lives. Zinc is integrally  involved in  transportation, medicine, energy conservation, pollution control, electronics, and space exploration. It has unique properties that allow it to contribute solutions to many problems, now and well into the future.

Zinc in Space

As a protective coating for steel, zinc has no equal. The steel and zinc industries  have worked together for many years to perfect galvanized coatings  capable of  protecting  steel  from corrosion, regardless of  the  environment  or application.  From automobile body panels and underbody  parts,  appliances, gas  pumps, mailboxes,  street furniture, vineyard wire and buildings, the life-extension and finishing options made possible by modern zinc coatings are staggering.

But  steel  is  not   the  only  material  to benefit  from  the  unique  properties of  zinc. When the US National Aeronautics and Space Administration  (NASA) scientists needed a coating  that  could  withstand  the  extreme

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Rob Putnam is Communications Manager at the International Lead Zinc Research Organization (ILZRO)  in the USA – rputnam@ilzro.org. Michael Martin is a consultant to International Zinc Association (IZA) – 106026.522@compuserve.com.

Zinc oxide is used in the manufacture of paints,

rubber  products,  cosmetics,   pharmaceuticals,

floor   coverings,   plastics,  printing   inks,   soap,

storage batteries, textiles, electrical equipment,

 …

temperatures  of   space travel,  they  turned  to   zinc  oxide. Researchers  were able to develop a zinc-based coating capable of  withstanding thermal cycling between 180° C  and –180° C, and  the  bombardment of  ultraviolet  exposure equivalent to 19,000 sun hours.   This zinc oxide coating is now routinely used to protect components of spacecraft, which are some of the most technically advanced and complex machines ever made.

     The Cassini probe

The Cassini  space  probe left  earth in 1997 on a seven-year voyage to Saturn. Upon arrival at Saturn, the probe will conduct a  four-year  mission with  fifty   orbits  and  numerous satellite encounters.  Several parts  of  the  Cassini probe, not  least of which its four-meter  diameter High Gain Antenna system,  are protected by a thermal control paint based on zinc oxide. This zinc-containing thermal coating is of critical importance to the probe because extreme temperatures will be encountered   as the probe approaches within 0.61 astronomical units (AU1) of the sun, during Venus flybys, and will be as far as 10 AU from the sun as it  orbits Saturn. A number of  coatings were evaluated for  the project, but the zinc oxide formula best met Mission requirements, including  the  ability  to  withstand  extreme temperatures  and ultraviolet exposure.

Zinc Undersea

As offshore oil production moves to deeper water, conventional production platforms become too costly. The required  mass of steel support structures  grows disproportionately as  the water depth increases.  To overcome this problem, an alternative technique is to set wellheads on the seabed and control their operation remotely. A series of electrical and hydraulic lines are used to link the remote wellhead to a production platform located in shallow water closer to shore.

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1 Astronomical Unit (AU) is the unit of distance used in the measurement of orbits and trajectories within the solar system. One AU is the average distance between the earth and the sun. Its value has been established  as, roughly, 149,600,000 km (92,960,000 miles).

Zinc Entertains

Despite  its  many  essential  uses,  sometimes  zinc

is  used purely for entertainment. Have you ever

wondered how things glow in the dark?All  glow-in-

the-dark products contain phosphors.A phosphor is

a substance  that  radiates visible light after being 

energized. To make a glow-in-the-dark  object,  you

 want a phosphor that  is energized by normal light

and that has a very  long persistence.  Zinc sulfide

has  these  properties and is used to create everything

from  luminescent watch dials to glow-in-the-dark toys.

Zinc’s  phosphorescent  properties  have  also made it a

 key ingredient in X-ray and TV screens, fluorescent

lights and light emitting diodes

Fireworks often make use of zinc dust to

create bright, shimmering sparks. The zinc

metal flakes heat up until they are incandescent

and shine brightly or, at a high enough temperature,

actually burn. A variety of chemicals can be added

to create the brilliant colors,

Until  recently,  these umbilical lines were made from  high- pressure plastic  hose, which  proved unsatisfactory over  long distances, or  from  metal  alloys, which  were cost prohibitive. Southwestern Pipe Inc., a  U.S.  company,   in  cooperation with Shell Oil and the International Lead Zinc Research Organization, developed a steel umbilical wrapped in a zinc cladding.  The ductile zinc cladding is extruded to a thickness of 750 microns (standard zinc coatings range between 8 and 40 microns) and has a life of 30-40 years undersea.  Today, the new zinc-protected umbilicals are commercialized  under the name of  SeaCAT.  SeaCAT  is now used on 75% of  deepwater projects in the Gulf of Mexico, with over 11 million feet (3.4 million metres) of the tubing in service. SeaCAT   is  also playing  a  pivotal  role  in  the  largest sub-sea development in the world, the BP Amoco – Shell Na Kika project. This remarkable engineering feat  will  consist of  five  sub-sea developments,  all tied back to  a permanently-moored floating production facility.   The wells are in water depths ranging from 5,800 to 7,000 feet (1,800 – 2,100 metres) and, when complete will require more than 1,000 miles (1,600 km) of zinc-clad tubing

 

BP Amoco – Shell Na Kika project

Zinc in Everyday Technology

Zinc castings are everywhere in  today’s  society,  from  light fixtures  to faucets, from door handles to car parts. Radios, fax machines, computers and printers are but a few of our modern technologies that rely on diecast zinc parts.Recently developed  casting techniques are fuelling  the race for  miniaturization of  ‘next generation’ convenience  appliances such as cell phones and laptop computers.  As more technology is packed into tighter spaces, the need to remove heat from sensitive electronic components  becomes critically important.  Researchers have turned to zinc alloys to cast the miniature heat sinks needed to cool these appliances. Zinc oxide varistors  are widely used in electrical systems  for circuit  protection.  Commonly known  as   surge arresters,  their primary function is to allow short-term circuit overloads to pass to ground. Most notably,  varistors  are used in high voltage power transmission lines as  protection  against lightning  strikes and temporary power  surges. They are also used in  low  voltage applications to protect sensitive components  such as  transistors and integrated circuits. Zinc plays a major role in the manufacture of  the  varistor.  The internal  component of  the  device is constructed almost entirely  of  zinc oxide. The outer  shell or casing  is  usually  a  ceramic  material  or   molded  rubber.

To  manufacture the internal zinc oxide block, zinc oxide is mixed with other metal oxides and a binder.  This powder mix is subjected to high pressure and formed into a disc, which is placed in a kiln and baked for several hours.  The zinc oxide particles fuse together to  form  a solid block. After a conductive coating is applied to the disc, multiple discs are stacked together and sealed in a shell. The size of the varistor varies in accordance with the voltage of the circuit to be protected. Zinc  oxide  in  this  ceramic form exhibits a unique electrical property – at design voltages, the block acts as a resistor, and at surge conditions, it acts as a conductor. Zinc is also a key ingredient in a new design of high-energy batteries. Researchers have already developed and commercialized a zinc-air battery capable of powering cell phones, hearing aids and laptop computers many hours longer than previously possible with  other battery chemistries.  Work is now ongoing to scale this and other zinc technology to  a size suitable for  powering automobiles and even homes. For example, the practice of truck engine idling, to  heat or cool sleeper cabs when the truck  is parked, may soon be replaced by zinc air fuel cells that provide quiet  and  clean auxiliary  power  for  truck  air-conditioning. America’s truckers currently spend as much as $4,000  per year per truck by idling engines to run auxiliary devices.Other uses  for  the  ultra-clean and quiet  zinc air  fuel  cell include forklifts and lawnmowers, scooters and delivery vehicles, back-up  generators  for  the  telecommunications industry  and auxiliary power for  boats, trucks and recreational vehicles, golf carts and industrial cleaning vehicles.

Zinc for Excellence

Each year, the U.S. National Academy of Recording

Arts & Sciences honors achievement in recorded music

with thepresentation of the Grammy® Award.The

Grammy is a peer honor, awarded annually, by and

to artists and technical professionalsfor artistic and

technical excellence.Befitting the recipient’s accomplishments,

the awards are hand-crafted from zinc alloysby an artisan

in Colorado.

exhibits a unique electrical property – at design voltages, the block acts as a resistor, and at surge conditions, it acts as a conductor.Zinc is also a key ingredient in a new design of high-energy batteries. Researchers have already developed and commercialized a zinc-air battery capable of powering cell phones, hearing aids and laptop computers many hours longer than previously possible with  other battery chemistries.  Work is now ongoing to scale this and other zinc technology to  a size suitable for  powering automobiles and even homes. For example, the practice of truck engine idling, to heat or cool sleeper cabs when the truck  is parked, may soon be replaced by zinc air fuel cells that provide quiet  and  clean auxiliary  power  for  truck air-conditioning. America’s truckers currently spend as much as $4,000  per year per truck by idling engines to run auxiliary devices.Other uses  for the  ultra-clean and quiet  zinc air  fuel  cell include forklifts  and lawnmowers, scooters and delivery vehicles, back-up  generators  for  the telecommunications industry  and auxiliary power for  boats, trucks and recreational vehicles, golf carts and industrial cleaning vehicles.

Looking Ahead

Despite a long history, zinc is a uniquely modern metal.  With its  vast array of  properties, zinc has few  peers  in  terms of usefulness in the ever-expanding fields of science and technology. Its versatility has made it a basic medium for researchers  as they probe new frontiers in physics, chemistry,  biology and electrical engineering.With  many thousands of  patents and literally  millions  of products to  its  credit, zinc played a supporting role in  many of the major inventions of the 20th Century.   From transistors to  lasers,  satellites to  circuit  boards, photocopiers  to  fuel cells, zinc is truly  among the most versatile and essential materials known to mankind.