Thermodynamic Analysis of Interfacial Reaction between Diamond and Ni-Cr Alloys

2010 ◽  
Vol 42 ◽  
pp. 440-443
Author(s):  
Zhi Bo Yang ◽  
Gui Bin Zhang ◽  
Jiu Hua Xu

Brazing diamond grits to steel substrate using Ni-based filler alloy was carried out via laser in an argon atmosphere. Thermodynamic analysis was performed in order to research the interfacial reaction mechanism of diamond and Ni-Cr alloy during high temperature brazing. Meanwhile, microstructure of the interfacial layer was experimentally detected by scanning electron microscope (SEM), energy dispersion spectrometer (EDS) and X-ray diffraction (XRD) in this paper. The results indicate that according to the thermodynamic theory the interfacial reaction has been proved feasible, and during brazing high strength bonding between diamond grits and the steel substrate has been successfully realized because the chromium in the Ni-based alloy segregated preferentially to the surface of the diamond to form a chromium-rich reaction product Cr3C2, and the bond between the alloy and the Diamond was established through the reaction product.

2007 ◽  
Vol 359-360 ◽  
pp. 53-57
Author(s):  
Bo Jiang Ma ◽  
Yu Can Fu ◽  
Wen Feng Ding ◽  
Wei Gao ◽  
Hong Jun Xu

The Ti-coated diamond and the uncoated diamond were brazed with Ni-based filler alloy by high-frequency induction under argon atmosphere at 1050°C within 15 seconds. The interfacial microstructures between brazed diamond and the filler alloy were analyzed by scanning electron microscopy (SEM), energy dispersion spectrometer (EDS) and X-ray diffraction (XRD). It is surprisedly found that Cr-carbides forms normally and compactly on the surface of Ti-coated diamond brazed, whereas Cr-carbide forms tangentially and loosely on the surface of uncoated diamond brazed. The abrade experiment results for the brazed diamonds show that the bond strength between the normally formed Cr-carbide and the diamond is higher than that between Cr-carbide and uncoated diamond brazed. Furthermore, the cause that Ti changes the morphology of Cr-carbides on the surface of Ti-coated diamond brazed is discussed by the further tests specially designed.


2010 ◽  
Vol 139-141 ◽  
pp. 218-221 ◽  
Author(s):  
Zhi Bo Yang ◽  
Ai Ju Liu ◽  
Jiu Hua Xu

Brazing diamond wheel was carried out via laser in an argon atmosphere. The interfacial microstructures among brazed diamond, the filler alloy and matrix were analyzed by scanning electron microscopy (SEM), energy dispersion spectrometer (EDS) and X- ray diffraction (XRD). The formation mechanism of carbide layers was also discussed. Finally, grinding examination of the grinding wheel was carried through. The results show that diamond can not fall off from the wheel even at heavy duty conditions.


2009 ◽  
Vol 87-88 ◽  
pp. 52-57
Author(s):  
Bo Jiang Ma ◽  
Zhu Ang Xu

The high-powered brazing diamond saw was developed to cut vehicle tyre efficiently. The Ti-coated diamond and the uncoated diamond were brazed with NiCr alloy by high-frequency induction under argon atmosphere at 1020°C within 10 seconds. The interfacial microstructures between brazed diamond and the filler alloy were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersion spectrometer (EDS). It is surprisedly found that Cr-carbides forms compactly and normally on the surface of Ti-coated diamond brazed, whereas Cr-carbide forms loosely and tangentially on the surface of uncoated diamond brazed. The abrade experiment results for the brazed diamonds show that the bond strength between the Cr-carbide and uncoated diamond brazed is lower than the normally formed Cr-carbide and the diamond. Furthermore, the cause that Ti changes the morphology of Cr-carbides on the surface of Ti-coated diamond brazed is discussed by the further tests that are specially designed.


2010 ◽  
Vol 97-101 ◽  
pp. 3879-3883 ◽  
Author(s):  
Zhi Bo Yang ◽  
Jiu Hua Xu ◽  
Ai Ju Liu

Brazing diamond grits onto steel substrate using a Ni-based filler alloy was carried out via laser beam in an argon atmosphere. The microstructure of the interfacial region among the Diamond grits and the filler layer were investigated by means of scanning electron microscopes (SEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). Meanwhile, the formation mechanism of carbide layers was discussed. All the results indicated that the active element chromium in the Ni-based alloy concentrated preferentially to the surface of the grits to form a chromium-rich layer, and the hard joint between the alloy and the steel substrate is established through a cross-diffusion of iron and Ni-based alloy through parameters optimization.


2007 ◽  
Vol 130 ◽  
pp. 97-100 ◽  
Author(s):  
Małgorzata Karolus ◽  
Edward Rówiński ◽  
Eugeniusz Łągiewka

Electrolytical layers of Ni-Mo alloys with polypyrrole, polytiofene and polyethylene were deposited on steel substrate (St3S, 4 cm2). After structural analyses of as quenched samples performed by X-ray diffraction it was noticed that the solid solution of Mo in Ni is observed. After annealing in an argon atmosphere the solid solution of Mo in Ni is becomeing more stable and crystalites are growing to the size of 200 – 300 Å. After annealing in an air atmosphere X-ray diffraction patterns show presence of phases: NiO, MoO, NiCO3, Mo2N. The unit cell parameters of solid solution after annealing are smaller than parameters of as quenched samples what means that the solid solution has been decomposing.


2011 ◽  
Vol 291-294 ◽  
pp. 954-957 ◽  
Author(s):  
Zhuo Ran Li ◽  
Guang Dong Wu ◽  
Xiang Long Zhang ◽  
Jian Xin Fan ◽  
Ji Cai Feng

Al2O3 is brazed with mild steel using 70Ag-27Cu-3Ti (wt.%) active filler alloy at 900°C for 5 min. The interfacial reaction products are analyzed with X-ray diffraction (XRD).The interfacial phases are analyzed with EDAX. According to the experimental observations, the interfaces developed during brazing have been systematically characterized and the structure are separately Ti3Cu3O/Ti3Al+ TiMn+TiFe2 +Ag(s,s)+Cu(s,s)/TiC from alumina ceramics side to mild steel side.


2009 ◽  
Vol 416 ◽  
pp. 396-400 ◽  
Author(s):  
Zhi Bo Yang ◽  
Ai Ju Liu ◽  
Jiu Hua Xu

Brazing diamond grits onto steel substrate using a Ni-based filler alloy was carried out via laser beam in an argon atmosphere. The microstructure of the interfacial region among the Diamond grits and the filler layer were investigated by means of scanning electron microscopes (SEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). Meanwhile, the formation mechanism of carbide layers was discussed. All the results indicated that the active element chromium in the Ni-based alloy concentrated preferentially to the surface of the grits to form a chromium-rich layer, and the hard joint between the alloy and the steel substrate is established through a cross-diffusion of iron and Ni-based alloy through parameters optimization.


2012 ◽  
Vol 490-495 ◽  
pp. 3486-3490
Author(s):  
Qiang Yu ◽  
Zhen Chen ◽  
Zhong Cheng Guo

In order to prepare a new type of anode material, stainless steel was selected as substrate material. The β-PbO2 coating on stainless steel substrate was prepared under the appropriate plating solution, and the PbO2-MnO2 coating was prepared with thermal decomposition. The crystal structure was determined by X-ray diffraction; Surface morphology was test by Scanning Electron Microscopy; the energy spectrum was used to determine element mass-fraction and the ratio of atomic number of the coatings.


2012 ◽  
Vol 727-728 ◽  
pp. 1387-1392 ◽  
Author(s):  
Luan M. Medeiros ◽  
Fernando S. Silva ◽  
Juliana Marchi ◽  
Walter Kenji Yoshito ◽  
Dolores Ribeiro Ricci Lazar ◽  
...  

Zirconium dioxide (zirconia) ceramics are known by its high strength and toughness and titanium dioxide (titania) ceramics has outstanding surface properties. The ceramic composite formed between the two oxides are expected to have advantages of both ceramics, especially when its surface area is increased by pores. In this work, ceramic composites of ZrO2-Y2O3-TiO2were synthesized by coprecipitation and rice starch was added as pore former in 10, 20 and 30 wt%. Powders were cold pressed as cylindrical pellets and sintered at 1500 °C for 01 hour and ceramics were characterized by techniques as Archimedes method for density measurements, X-ray diffraction and scanning electron microscopy. Results showed that pores are inhomogeneously distributed through ceramic bodies.


2008 ◽  
Vol 591-593 ◽  
pp. 147-153
Author(s):  
Gilbert Silva ◽  
Erika Coaglia Trindade Ramos ◽  
N.S. da Silva ◽  
Alfeu Saraiva Ramos

A large amount of the Ti6Si2B compound can be formed by mechanical alloying and subsequent heat treatment from the elemental Ti-22.2at%Si-11.1at%B powder mixture, but the yield powder after ball milling is reduced due to an excessive agglomeration of ductile particles on the balls and vial surfaces. This work reports on the structural evaluation of Ti-22.2at%Si-11.1at%B powders milled with PCA addition, varying its amount between 1 and 2 wt-%. The milling process was carried out in a planetary ball mill under argon atmosphere, and the milled powders were then heated at 1200oC for 1h under Ar atmosphere in order to obtain equilibrium structures. Samples were characterized by X-ray diffraction, scanning electron microscopy, and thermal analysis. Results revealed that the PCA addition reduced the excessive agglomeration during the ball milling of Ti-22.2at-%Si-11.1at-%B powders. After heating at 1200oC for 1h, the Ti5Si3, Ti3O and/or Ti2C phases were preferentially formed in Ti-22.2at%Si-11.1at%B powders milled with PCA addition, and the Ti6Si2B formation was inhibited.


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