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.

Studies on HPHT synthesis and N defects of N-rich B-doped diamonds

CrystEngComm ◽  
2018 ◽  
Vol 20 (44) ◽  
pp. 7109-7113 ◽  
Author(s):  
Xinyuan Miao ◽  
Liangchao Chen ◽  
Hongan Ma ◽  
Chao Fang ◽  
Longsuo Guo ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Temperature Gradient ◽  
Single Crystal ◽  
High Quality ◽  
Temperature Conditions ◽  
Ni Content ◽  
Growth Method

In this paper, high-quality N-rich single crystal diamonds with different boron additive contents were synthesized in NiMnCo alloy with high Ni content by the temperature gradient growth method under HPHT (high pressure and high temperature) conditions.

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.

Synthesis and characterization of boron and nitrogen co-doped diamond crystals under high pressure and high temperature conditions

CrystEngComm ◽  
2017 ◽  
Vol 19 (31) ◽  
pp. 4571-4575 ◽  
Author(s):  
Meihua Hu ◽  
Ning Bi ◽  
Shangsheng Li ◽  
Taichao Su ◽  
Qiang Hu ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Temperature Gradient ◽  
Gradient Method ◽  
Synthesis And Characterization ◽  
Temperature Conditions ◽  
Diamond Crystals ◽  
Temperature Gradient Method ◽  
Co Doped

In this study, diamond crystals co-doped with boron and nitrogen were synthesized via a temperature gradient method at 5.3–5.8 GPa and 1300–1550 °C by adding B and N dopants to a system of carbon and an Fe-based solvent catalyst.

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.

Influence of carbon convection field on high quality large single crystal diamonds morphology under high pressure and high temperature

RSC Advances ◽  
2016 ◽  
Vol 6 (46) ◽  
pp. 40330-40335 ◽  
Author(s):  
Yadong Li ◽  
Xiaopeng Jia ◽  
Bingmin Yan ◽  
Ning Chen ◽  
Chao Fang ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Temperature Gradient ◽  
Single Crystal ◽  
Large Single Crystal ◽  
High Quality

The temperature and convection fields of a catalyst with three different heights were simulated in a temperature gradient growth (TGG) system under high pressure and high temperature (HPHT) conditions.

scholarly journals Macrodefects in Cubic Silicon Carbide Crystals

2010 ◽  
Vol 645-648 ◽  
pp. 375-378 ◽  
Author(s):  
Valdas Jokubavicius ◽  
Justinas Palisaitis ◽  
Remigijus Vasiliauskas ◽  
Rositza Yakimova ◽  
Mikael Syväjärvi
Keyword(s):  
Growth Rate ◽  
Silicon Carbide ◽  
Crystal Growth ◽  
High Temperature ◽  
Temperature Gradient ◽  
Early Stage ◽  
Growth Conditions ◽  
Temperature Ramp ◽  
Cubic Silicon Carbide ◽  
Sublimation Growth

Different sublimation growth conditions of 3C-SiC approaching a bulk process have been investigated with the focus on appearance of macrodefects. The growth rate of 3C-SiC crystals grown on 6H-SiC varied from 380 to 460 μm/h with the thickness of the crystals from 190 to 230 μm, respectively. The formation of macrodefects with void character was revealed at the early stage of 3C-SiC crystal growth. The highest concentration of macrodefects appears in the vicinity of the domain in samples grown under high temperature gradient and fastest temperature ramp up. The formation of macrodefects was related to carbon deficiency which appear due to high Si/C ratio which is used to enable formation of the 3C-SiC polytype.

An Investigation of Heat Affected Zone of Round Steel Rods Welded by Friction Welding

2012 ◽  
Vol 217-219 ◽  
pp. 2198-2201
Author(s):  
Chawalit Thinvongpituk ◽  
Surasing Arayangkun
Keyword(s):  
High Temperature ◽  
Temperature Gradient ◽  
Heat Affected Zone ◽  
Friction Welding ◽  
Welding Process ◽  
High Strength ◽  
High Quality ◽  
Joint Property ◽  
Welding Technique

Friction welding is a welding technique that has been studied and developed continuously. This is due to its advantages, such as it provides high quality of joint, high strength of joint. It can make welded zone through the whole section without bubble. However, there is heat generated in the welding process that can change the phase of materials. Hence, the hardness and strength of joint are affected. This paper is aimed to investigate the microstructure at the joint, which is called heat affected zone. The experiment was conducted with a number of steel rods of 10 mm. diameter. The welded specimens were tested for strength, hardness and microstructure. The temperature gradient of specimen under welding process was also recorded. It was revealed that the strength of welded element is higher but the hardness is lower. The photo of thermo scan revealed that heat is generated around the lip of interface, resulting high temperature in heat affected zone. This causes some change in microstructure composition as well as joint property.

Sign in / Sign up

Export Citation Format

Share Document