Impaction of Graphite Type on Performance of Polycrystalline Diamond Powder

2012 ◽  
Vol 535-537 ◽  
pp. 2507-2512
Author(s):  
Chun Lin Li ◽  
Jian Chen

Taking different types of graphite as raw materials , polycrystalline diamond powder is prepared by shock wave synthesis through copper to absorb and transfer the heat in the article. Yield and abrasion resistance performance are tested, and impaction of graphite crystallite structure on the yield and abrasion resistance performance is researched. As the result, diamond yield and abrasion resistance synthesized from scale graphite is not as good as from earthy graphite. It is easy for polycrystalline diamond powder synthesized from artificial graphite which crystallite has parallel coke-base to graphitize and difficult to get diamond. Yield of artificial graphite which crystallite has disorderly carbon black base is higher than that of earthy graphite, there are more pores for the first baked artificial graphite of carbon black base, the abrasion resistance performance of synthesized diamond is worse than earthy graphite, and the abrasion resistance performance of the second baked polycrystalline diamond powder is better than earthy graphite.

2012 ◽  
Vol 550-553 ◽  
pp. 93-98
Author(s):  
Chun Lin Li ◽  
Jian Chen

Taking earthy graphite and electrolytic powder as raw materials, copper/graphite raw material is prepared by power metallurgy and then polycrystalline diamond powder is prepared by shock wave synthesis. Impaction on yield and abrasion resistance from copper content, particle size of graphite powder, heat treatment and re-pressing process has been researched. As result, yield of polycrystalline diamond powder is decreasing as decreasing copper content. It is decreased dramatically when the copper content is less than 90%. It is increased and then decreased as increasing the particle size of graphite powder, and the better particle size of graphite powder is 70μm. It is increased slightly and then decreased dramatically as increasing heat treatment temperature before re-pressing. The higher the heat treatment temperature, the more the yield after re-pressing. Impaction on the abrasion resistance of polycrystalline diamond powder from the preparing process of copper/graphite is smaller.


1944 ◽  
Vol 17 (2) ◽  
pp. 451-474
Author(s):  
D. Parkinson

Abstract Carbon blacks can be grouped into different classes according to the way in which their fineness of division relates to different properties in rubber. Within any one class the principal properties vary in a regular manner with particle size. The normal class consists of the furnace carbons, Kosmos (Dixie)-40, Statex, the rubber-grade impingement carbons, and possibly, the color-grade impingement carbons. The subnormal classes consist of thermal carbons and acetylene and lamp blacks. Irrespective of the above classification, the properties which depend more on fineness of division than on other factors are rebound resilience, abrasion resistance, tensile strength and tear resistance. The lower limit of particle diameter for best tensile strength and tear resistance appears to be higher than that for abrasion resistance. B.S.I, hardness and electrical conductivity are properties which depend at least as much on other factors as on particle size. Stiffness (modulus) depends more on other factors than on particle size. Factors modifying the effects of particle size (or specific surface) include the presence of carbon-carbon structures and a reduction in strength of bond in rubber-carbon structures. Carbon black is thought to exist in rubber in four states: agglomerated, flocculated, dispersed, and bonded to the rubber molecules (the reënforcing fraction). Abrasion resistance is regarded as providing the only reliable measure of reënforcement.


2012 ◽  
Vol 476-478 ◽  
pp. 194-198 ◽  
Author(s):  
Zhi Chao Chen ◽  
Zheng Liang Xue ◽  
Wei Wang ◽  
Yue Yu ◽  
Qiang Liu ◽  
...  

Keywords: vanadium pentoxide;carbon black;reduction and nitridation;vanadium nitrogen alloy. Abstract. The V2O5 extracted from low vanadium shale and carbon black are used as raw materials to prepare briquetting samples through mixing, grinding and pressing. The samples are prereduced, final reduced and nitrated to produce vanadium nitrogen alloy with high nitrogen content. Thermodynamic analysis and experiment results show that:(1)In order to avoid V2O5 volatilization loss during reduction, the briquetting samples should be pre-reduced for 4 hours below the melting point 670°C of V2O5, which can transform V2O5 into low valence vanadium oxide.(2)During V2O5 being self-reduction under N2 atmosphere, if the final reduction temperature is below 1271°C, the VN is preferential formation; if more than 1271°C, the reduced product forms V4C3.(3)To make a product with high nitrogen and low carbon content, the final reduction and nitride temperature should be controlled below 1300°C.


2011 ◽  
Vol 399-401 ◽  
pp. 855-859
Author(s):  
Ting Ting Wu ◽  
Bo Lin Wu

In order to improve the acid resistance and reduce the apparent density of fracturing proppants, TiO2 powder added in the system of BaO-MgO-Al2O3 fracturing proppants were prepared by the technique of pressureless sintering. The properties of the samples were investigated by the measurements of acid solubility, X-ray diffraction and scanning electron microscopy. The results show that the acid solubility of alumina matrix fracturing proppants contenting TiO2 of the 4wt% and BaO/MgO with the ratio of 3:7 is 0.15%. It is an important development in acid resistance performance of fracturing proppants research on laboratory. TiO2 is added to the raw materials and then calcine them to ceramics, which can reduces the sintering temperature, promote the densification and improve acid-resistant property of fracturing proppants.


2010 ◽  
Vol 660-661 ◽  
pp. 844-847 ◽  
Author(s):  
Ana Lúcia Diegues Skury ◽  
Sérgio Neves Monteiro ◽  
Guerold Sergueevitch Bobrovinitchii ◽  
Marcia G. de Azevedo

It is still in focus the problem of obtaining high quality polycrystalline materials by means of sintering fine diamond powders. The most important task of this problem is the consolidation or improvement of the processed polycrystalline diamond. It is worldwide recognized that the plastic deformation of the diamond particles performs the most important role on the diamond powder consolidation. In some cases, the contact and shear tensions reconstruct the compact structure. In this work the sintering process used a mixture of micro and nanodiamonds. The sintering process was carried out in a toroidal high-pressure device. The effects of nanodiamond addition and sintering conditions on the microstructure and mechanical properties sintered diamond bodies were studied. The sintering parameters were pressure of 6.8 GPa and a temperature of 1850 K, and these conditions were maintained for 1 minute. Homogeneous sintered bodies were obtained, which have a Vickers' hardness over 40 GPa, and fracture toughness around 7.1 – 7.9 MPa.m1/2.


2019 ◽  
Vol 12 (2) ◽  
pp. 83 ◽  
Author(s):  
Carlos Eduardo Peixoto da Cunha ◽  
Edson Silvio Batista Rodrigues ◽  
Morgana Fernandes Alecrim ◽  
Douglas Vieira Thomaz ◽  
Isaac Yves Lopes Macêdo ◽  
...  

Diclofenac (DIC) is a non-steroidal anti-inflammatory drug of wide use around the world. Electroanalytical methods display a high analytical potential for application in pharmaceutical samples but the drawbacks concerning electrode fouling and reproducibility are of major concern. Henceforth, the aim of this work was to propose the use of alternative low-cost carbon black (CB) and ionic liquid (IL) matrix to modify the surface of pencil graphite electrodes (PGE) in order to quantify DIC in raw materials, intermediates, and final products, as well as in stability assays of tablets. The proposed method using CB+IL/PGE displayed good recovery (99.4%) as well as limits of detection (LOD) of 0.08 µmol L-1 and limits of quantification (LOQ) of 0.28 µmol L−1. CB+IL/PGE response was five times greater than the unmodified PGE. CB+IL-PGE stands as an interesting alternative for DIC assessment in different pharmaceutical samples.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Pongdhorn Sae-oui ◽  
Krisda Suchiva ◽  
Chakrit Sirisinha ◽  
Wenussarin Intiya ◽  
Pram Yodjun ◽  
...  

This work aimed at investigating the effects of blend ratio between styrene butadiene rubber (SBR) and butadiene rubber (BR) and SBR type (E-SBR and S-SBR) on properties of SBR/BR tire tread compounds. Influences of these parameters on properties of the tread compounds reinforced by 80 parts per hundred rubber (phr) of carbon black (CB) and silica were also compared. Results reveal that hardness, strengths, and wet grip efficiency were impaired whereas rolling resistance was improved with increasing BR proportion. Surprisingly, the presence of BR imparted poorer abrasion resistance in most systems, except for the CB-filled E-SBR system in which an enhanced abrasion resistance was observed. Obviously, S-SBR gave superior properties (tire performance) compared to E-SBR, particularly obvious in the silica-filled system. Compared with CB, silica gave comparable strengths, better wet grip efficiency, and lower rolling resistance. Carbon black, however, offered greater abrasion resistance than silica.


2007 ◽  
Vol 336-338 ◽  
pp. 939-941
Author(s):  
Yong Qiang Meng ◽  
Zhi Min Bai ◽  
Chang Hong Dai ◽  
Bao Bao Zhang

A new method for producing silicon carbide platelets with low cost and high yield was introduced. The silicon carbide platelets were synthesized by powder-heating techniques with carbon black and SiO2 powder as raw materials and CoCl2 as catalyst. The starting mixtures were heated at a temperature in the range of 1800-2000°C for the duration of about 2-4h to produce substantially completely unagglomerated silicon carbide platelets with a thickness of 5-20μm and the average diameter of 50-200μm. Compared to the conventional heating, the powder-heating technique is advantageous of less investment on equipment, easy to manufacture and convenient to operate. Furthermore, it is very suitable for realizing the scaled production because of the lower synthesizing temperature, shorter reaction time and greater output.


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