Investigation of the Crystal Defects in Synthesized Diamond by Synchrotron Radiation Topography

2013 ◽  
Vol 721 ◽  
pp. 109-112
Author(s):  
Wan Li Yu ◽  
Xiao Peng Jia ◽  
Qing Xi Yuan
Keyword(s):  
Growth Rate ◽  
High Pressure ◽  
High Temperature ◽  
Synchrotron Radiation ◽  
Metastable State ◽  
Diamond Crystal ◽  
Natural Diamond ◽  
Crystal Defects ◽  
Natural Diamonds ◽  
Large Diamond

Crystal defects in a large diamond crystal synthesized by high pressure and high temperature (HPHT) method were investigated by synchrotron radiation topography. Five bundles of dislocations were observed in the specimen. Two bundles of the dislocations are in the <100> direction and three of the others are extended at <110>. The Burgers vectors of the dislocations are different within the same bundle as the extinction hinted. The dislocations in <100> direction possess higher energy than the dislocations in <110> and {111}, so they are in the metastable state. The <100> dislocations has not been found in natural diamond yet. The reason of that was the great difference of the growth rate of synthetic and natural diamonds.

Effect of Ni70Mn25Co5 or Fe55Ni29Co16 on the Growth of Type-II a Large Diamonds with Al as Nitrogen Getter

2011 ◽  
Vol 266 ◽  
pp. 89-92
Author(s):  
Shang Sheng Li ◽  
Ning Luo ◽  
Xiao Lei Li ◽  
Tai Chao Su ◽  
You Mou Zhou ◽  
...  
Keyword(s):  
Growth Rate ◽  
High Pressure ◽  
High Temperature ◽  
Temperature Gradient ◽  
Nitrogen Concentration ◽  
Type Ii ◽  
High Quality ◽  
Quality Type ◽  
Temperature Gradient Method ◽  
Large Diamond

With adopting Al as the nitrogen getter in Ni70Mn25Co5 or Fe55Ni29Co16 catalyst, High-quality type-Ⅱa large diamonds have been grown under the conditions of about 5.5GPa and 1580K by using the temperature gradient method. While Al(2.0wt%) is added in the Fe55Ni29Co16, the nitrogen concentration(Nc) in the diamond is less than 1ppm. While Al(4.0wt%) is added in the Ni70Mn25Co5, the Nc in the diamond is highly arrived at 48ppm. The different of solubility of nitrogen in both catalyst at high pressure and high temperature is the basic reason of the different effect of eliminating nitrogen of Al. It can be shown in experamentals that Al is a less efficient nitrogen getter in Ni70Mn25Co5 than in Fe55Ni29Co16. While Al(2.0wt%) is added in the Fe55Ni29Co16, the high-quality type-Ⅱa large diamond, in which nitrogen is less than 1ppm and which the size was arrived at 3.3mm, had grown by decreasing the growth rate of diamond.

Reconstruction of the Growth History of a Large Synthesized Diamond Crystal by Synchrotron Topography

2013 ◽  
Vol 739 ◽  
pp. 7-11
Author(s):  
Wan Li Yu ◽  
Xiao Peng Jia ◽  
Qing Xi Yuan
Keyword(s):  
Synchrotron Radiation ◽  
Temperature Gradient ◽  
Growth Stage ◽  
Diamond Crystal ◽  
Early Stage ◽  
Crystal Defects ◽  
Growth History ◽  
History Of ◽  
Temperature Gradient Method ◽  
Large Diamond

The growth history of a large diamond crystal synthesized by HPHT temperature gradient method was reconstructed by the defects features in the crystal. The crystal defects were revealed using white synchrotron radiation topography. Dislocations originated from the surfaces of the seed and extended along the directions of <100> were observed within the crystal grown at the early stage. The crystal was then grown to the [00-direction at the middle growing stage and no dislocations were generated at this stage. A lot of dislocation bundles were generated at the last growth stage of the crystal and each bundle was composed of several straight extended dislocations originated from the same point and extended radially within a sector of about thirty degrees centigrade. The origins of the dislocation bundles were distributed near the surface of the crystal. Most of the dislocation bundles were generated near the (-100), (010) and (00-1) and extended to the [-10, [01 and [00-, approximately. The generation of the dislocation bundles was caused by the rapid descent of the temperature in the last growth stage of the diamond crystal.

Diamond radiation detector made of an ultrahigh-purity type IIa diamond crystal grown by high-pressure and high-temperature synthesis

2001 ◽  
Vol 72 (2) ◽  
pp. 1406 ◽  
Author(s):  
Teruya Tanaka ◽  
Junichi Kaneko ◽  
Daisuke Takeuchi ◽  
Hitoshi Sumiya ◽  
Masaki Katagiri ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Diamond Crystal ◽  
Radiation Detector ◽  
Temperature Synthesis ◽  
High Temperature Synthesis

HPHT Growth and IR Characterizaton of Large Diamond Crystals in FeNi-C-FeS Systems

2011 ◽  
Vol 339 ◽  
pp. 491-495
Author(s):  
Chuan Yi Zang ◽  
Lun Jian Chen ◽  
Li Xue Chen
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Boron Content ◽  
Diamond Crystals ◽  
Growth System ◽  
Negative Effect ◽  
Temperature Gradient Method ◽  
Co Doped ◽  
Large Diamond

By temperature gradient method (TGM), with Invar alloy as solvent catalyst, FeS and boron as additives, large diamond crystals are grown under high pressure and high temperature (HPHT) of about 5.4GPa and 1550K. With the content of FeS increased, the colors of grown crystals would be changed from transparent yellow to opaque gray-black, and the quality of diamond crystals could also be destroyed markedly. When both boron and FeS co-doped, the negative effect of FeS on crystal quality could be eliminated somewhat. To a certain content of FeS, with the boron content increased, the crystal color would be changed from opaque gray-black to transparent yellow, and boron content needed is related directly to FeS content in growth systems. The nitrogen content in diamond lattice decreases greatly, with FeS content increased in the growth system, and a 1050cm-1 absorption peak in IR spectrum is also present in diamond crystals grown in FeNi-FeS-C system.

Transformation of Nitrogen State in High-Level N-Doped Gem-Quality Diamond Crystal Annealed at High Temperature and High Pressure

2012 ◽  
Vol 29 (10) ◽  
pp. 106102 ◽  
Author(s):  
Guo-Feng Huang ◽  
Xiao-Peng Jia ◽  
Hong-An Ma ◽  
Hong-Bo Bai ◽  
Ji-Wen Yin ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Diamond Crystal ◽  
High Level
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