Like an ice cube in a hot day, most materials melt - that is, moving from solid to liquid when heated. But there are exceptions: a couple of ... A group of scientists from the Massachusetts Institute of Technology found that such unusual properties have, and silicon, are widely used in computer chips and solar cells. ...
The compound of silicon, copper, nickel and iron melts (actually goes from solid to liquid state or in a kind of slurry ) at a temperature below 900 ° C, while silicon is usually melts at 1414 ° C. Much lower temperatures are possible to observe the behavior of the material during melting, based on the use of specialized technology X-ray microprobe using synchrotron - a particle accelerator such as - as a source of.
The study may lead to a decrease in the cost of some silicon-based devices, especially those in which a small amount of impurities can significantly reduce the performance. For example, for the manufacture of solar cells can be made less pure and therefore less expensive, silicon, which will be cleaned during the manufacturing process.
...
Back in 2007 Buonassisi predicted the possibility of retrograde melting of silicon. But only recently, scientists were able to obtain all the necessary conditions for achieving such a state and its study at the microscopic level.
The material that was used by scientists, was a kind of sandwich of two thin layers of silicon with the ... First, the object was heated to a temperature that caused the dissolution of metals in silicon (in this case it did not reach its melting temperature ). Significant amounts of the metal led to a ... For example, when a liquid is heated, it can dissolve more of the other stuff, but then, on cooling, it becomes saturated - until such time as the excess impurities do not precipitate.
As researchers studied when dissolved metals in the solid silicon, cooled to a certain point led to the formation of precipitation. ... That's when the material begins to melt.
Source: mit. edu.
No comments:
Post a Comment