by Staff Writers
Nuremberg, Germany (SPX) Mar 27, 2017
Material researchers of Friedrich-Alexander Universitat Erlangen Nurnberg (FAU) have come a step closer to their goal of providing large diamond foils for practical applications. In a test reactor, they have succeeded in producing the world's largest diamond foil with a diameter of 28 centimetres. Diamond foils can be used as ultimate wear protection in industrial applications and for research into thermoelectric power generation - an emerging market.
Diamonds are not only considered valuable, but also virtually indestructible. They are one of the hardest natural materials in our universe. Consequently, it is not surprising that producing diamond foils has become a key area in materials science research, particularly as these layers feature extreme hardness and wear resistance, exceptional chemical inertness and maximum thermal conductivity. Unfortunately, coating substrates directly with crystalline diamond is only possible on a limited range of materials.
The research group 'Ultra Hard Coatings' at FAU's Chair of Materials Science and Technology of Metals has developed a process of growing diamond coatings on silicon substrates which can be used on materials which are not suitable for direct coating. They have now succeeded in producing the world's largest diamond foil with a diameter of 28 centimetres.
'By scaling up the manufacturing process, we have demonstrated that we can produce diamond foils in future as a semi-finished product for industry even in large dimensions,' explains Dr. Stefan Rosiwal, head of the Ultra Hard Coatings research group at the Chair of Materials Science and Technology of Metals.
'In these diamond layers, we can adjust the diamond grain size, the electrical conductivity and thermal conductivity by varying the manufacturing parameters by many orders of magnitude.'
After the coating process, a short pulse laser is used to introduce a circular fracture site with a diameter of 28.5 centimetres into the diamond surface. This makes it possible to separate the deposited layer as a very smooth diamond foil from the silicon substrate.
Now that researchers have demonstrated diamond foil manufacturing processes successfully on a larger scale, this opens up opportunities for coating industrial components directly in a more cost effective way. Such industrial components include wear-resistant layers for mechanical seals in pumps as well as the production of stable diamond electrodes for highly efficient water purification and disinfection systems.
These innovative diamond electrode systems are used for washing and disinfecting oranges after harvesting in southern Europe, removing putrefying bacteria from the surface of the fruit and saving up to 80% water. In the future, the technology could be used on container ships or sewage treatment plants. Diamond electrodes may even help in washing machines by keeping clothes clean and fresh at significantly lower temperatures.
The findings were published under the titles 'Mechanical properties of micro- and nanocrystalline diamond foils' and 'Thermoelectric transport properties of boron-doped nanocrystalline diamond foils' in the renowned scientific journals Philosophical Transactions A doi:10.1098/rsta.2014.0136 and Carbon doi:10.1016/j.carbon.2014.10.002.
Santa Barbara CA (SPX) Mar 17, 2017
The oceans are great at absorbing carbon dioxide (CO2) from the air, but when their deep waters are brought to the surface, the oceans themselves can be a source of this prevalent greenhouse gas. Wind patterns together with the Earth's rotation drive deep ocean water - and the CO2 it sequesters - upward, replacing surface water moving offshore. A process known as upwelling, it occurs on th ... read more
University of Erlangen-Nuremberg
Carbon Worlds - where graphite, diamond, amorphous, fullerenes meet
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