The Experts below are selected from a list of 582 Experts worldwide ranked by ideXlab platform
Esteba E Aglietti - One of the best experts on this subject based on the ideXlab platform.
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Carbonitriding of zro2 relation between the weight loss and crystalline phase evolution during reaction
Materials Chemistry and Physics, 2005Co-Authors: S Tamborenea, Alfredo D Mazzoni, Esteba E AgliettiAbstract:Abstract Carbonitriding reactions of ZrO2 permit to obtain Zr(C,O,N) phases that belong to the pseudoternary “ZrO–ZrN–ZrC” system. The Zr(C,O,N) phase has cubic crystalline structure with a0 parameter depending on the C, O and N content. The formation reaction of the Zr(C,O,N) phases was followed using X-ray diffraction (XRD) and the weight loss (WL) data. The reaction was studied employing different carbon contents (15–31%) at temperatures from 1400 to 1650 °C. The β″-phase (Zr7O9.5N3.0) was the unique secondary product formed. The crystallite sizes of the zirconium phases were also determined by XRD. Some samples were analyzed using the Rietveld method with silicon as internal standard. Using the Carbonitriding process a Zr(C,O,N) phase was obtained and the loss weight is a parameter permitting to control the reaction products. The oxidation resistance of the Zr(C,O,N) phase was studied employing differential thermal analysis (DTA)–thermogravimetric analysis (TG) techniques. Additionally, microstructure analysis of raw materials and reaction products were performed by scanning electronic microscopy (SEM).
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Carbonitriding of clay relation between the weight loss and crystalline phases during reaction
Journal of the American Ceramic Society, 1993Co-Authors: Alfredo D Mazzoni, Esteba E Aglietti, Enrique PereiraAbstract:β'-Sialons are phases of the Si-Al-O-N system. The Carbonitriding of clays and kaolins is a preparation method. The reaction mechanism of clay Carbonitriding is verified by means of the relation among crystalline phases formed and the weight loss produced in the samples during the reaction. Two clays were previously mixed with carbon black and pressed into pellets, flowing through N2 atmosphere, at five temperatures within the range 1335–1427°C. The phases formed (XRD)—mullite, SiC, β′A-sialon, and oxynitrides—were related to the weight loss measured in the pellet independently of reaction temperature and time. The β′A-sialon and the nitrogenous phases were formed from SiC and mullite. A z value decrease for β′A-sialon was observed during reaction progression.
Young Hoo Moo - One of the best experts on this subject based on the ideXlab platform.
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Carbonitriding of ti 6al 4v alloy via laser irradiation of pure graphite powder in nitrogen environment
Surface & Coatings Technology, 2019Co-Authors: Dong Myeong Seo, Tae Woo Hwang, Young Hoo MooAbstract:Abstract In the study, an innovative Carbonitriding process was implemented to increase hardness and hardening depth of Ti-6Al-4V alloy via laser irradiation of pure graphite powder in a nitrogen environment. The formation of the carbonitrided layer on the surface depends on the diffusion of carbon and nitrogen atoms and the kinetics of Carbonitriding reaction. Dendritic phase transformations within the hardened layer help in determining the overall depth and hardness of the hardened layer. To characterize the proposed Carbonitriding process more fundamentally, samples of an Ti-6Al-4V alloy were self-quenched (SQ), laser-carburized (LC), laser-nitrided (LN), and laser‑carbonitrided (LCN) at the same laser irradiation conditions. This was followed by comparing the microstructural evolutions and mechanical properties of the respective samples after laser surface treatments. The hardening characteristics of the respective laser surface treatments were significantly influenced by the reaction compounds and laser energy density. The LCN Ti-6Al-4V alloy was dominated by compounds with mixed structure of carbonitrides and exhibited excellent hardness with increase in hardening depth. The results confirmed that the proposed laser Carbonitriding is a feasible and effective process to increase the hardness and hardening depth of Ti-6Al-4V alloy without process-induced cracks.
Alfredo D Mazzoni - One of the best experts on this subject based on the ideXlab platform.
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Carbonitriding of zro2 relation between the weight loss and crystalline phase evolution during reaction
Materials Chemistry and Physics, 2005Co-Authors: S Tamborenea, Alfredo D Mazzoni, Esteba E AgliettiAbstract:Abstract Carbonitriding reactions of ZrO2 permit to obtain Zr(C,O,N) phases that belong to the pseudoternary “ZrO–ZrN–ZrC” system. The Zr(C,O,N) phase has cubic crystalline structure with a0 parameter depending on the C, O and N content. The formation reaction of the Zr(C,O,N) phases was followed using X-ray diffraction (XRD) and the weight loss (WL) data. The reaction was studied employing different carbon contents (15–31%) at temperatures from 1400 to 1650 °C. The β″-phase (Zr7O9.5N3.0) was the unique secondary product formed. The crystallite sizes of the zirconium phases were also determined by XRD. Some samples were analyzed using the Rietveld method with silicon as internal standard. Using the Carbonitriding process a Zr(C,O,N) phase was obtained and the loss weight is a parameter permitting to control the reaction products. The oxidation resistance of the Zr(C,O,N) phase was studied employing differential thermal analysis (DTA)–thermogravimetric analysis (TG) techniques. Additionally, microstructure analysis of raw materials and reaction products were performed by scanning electronic microscopy (SEM).
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Carbonitriding of clay relation between the weight loss and crystalline phases during reaction
Journal of the American Ceramic Society, 1993Co-Authors: Alfredo D Mazzoni, Esteba E Aglietti, Enrique PereiraAbstract:β'-Sialons are phases of the Si-Al-O-N system. The Carbonitriding of clays and kaolins is a preparation method. The reaction mechanism of clay Carbonitriding is verified by means of the relation among crystalline phases formed and the weight loss produced in the samples during the reaction. Two clays were previously mixed with carbon black and pressed into pellets, flowing through N2 atmosphere, at five temperatures within the range 1335–1427°C. The phases formed (XRD)—mullite, SiC, β′A-sialon, and oxynitrides—were related to the weight loss measured in the pellet independently of reaction temperature and time. The β′A-sialon and the nitrogenous phases were formed from SiC and mullite. A z value decrease for β′A-sialon was observed during reaction progression.
A D Mazzoni - One of the best experts on this subject based on the ideXlab platform.
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study of Carbonitriding reactions of zirconia synthesis of zr c n o phases and β type zirconium oxynitrides
Ceramics International, 2004Co-Authors: A D Mazzoni, M S ConconiAbstract:Abstract Carbonitriding reactions of ZrO 2 permit obtaining Zr(C,O,N) phases that belong to the pseudoternary “ZrO–ZrN–ZrC” system and/or β-type zirconium oxynitrides belonging to the ZrO 2 –Zr 3 N 4 system. The Zr(C,O,N) phase has a cubic crystalline structure with a o parameter depending on the C, O and N content. The β- type oxynitride obtained was the β″-phase corresponding to the Zr 7 O 9,5 N 3,0 formula with trigonal crystalline structure. The Zr(C,O,N) composition ( a o between 4.600 and 4.654 A) and relative proportions of both phases depend on the reaction temperature (between 1400 and 1650 °C) and on the carbon content of the samples (between 0 and 33%). The reaction products were studied by X-ray diffraction (XRD). Some samples were analyzed using the Rietveld method with silicon as internal standard. The crystallite sizes of the zirconium phases were also determined by XRD. Additionally, microstructure analysis of raw materials and reaction products were performed by scanning electronic microscopy (SEM).
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synthesis of zr si o n phases by Carbonitriding reaction characterization of crystalline phases using the rietveld method
Materials Research-ibero-american Journal of Materials, 2001Co-Authors: A D Mazzoni, M S Conconi, E F AgliettiAbstract:Zirconium compounds are of great interest for ceramic application due to their excellent thermal and mechanical properties. Zirconium phases of the system Zr-O-C-N were obtained using Carbonitriding reactions of zircon mineral (ZrO2.SiO2), under different reaction conditions. The reaction products were studied by X-ray diffraction (XRD) using the Rietveld method. Silicon was employed as internal standard. Zirconium compounds formed were m-ZrO2 (monoclinic), b"-zirconium oxynitride and a cubic Zr(C,N,O) phase whose lattice parameter ao depends on the composition. The crystallite sizes of the three zirconium phases were determined also by XRD. The minority phases present are the ones of the Si-O-N-C system. The reaction conditions employed allows to obtain reaction products with low or without silicon content.
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mechanism of the Carbonitriding reactions of sio2 al2o3 minerals in the si al o n system
Applied Clay Science, 1998Co-Authors: A D Mazzoni, E F AgliettiAbstract:Abstract Ceramics of the Si–Al–O–N system and SiC have a great technological interest because of their good thermomechanical properties at high temperatures. It is possible to obtain phases such as β -SiC, Si 3 N 4 , β ′-sialons, O′-sialons, polytype sialons, AlN, Al 2 O 3 or mixtures of these phases by means of Carbonitriding reactions starting from minerals such as quartz, diatomite and other aluminosilicate minerals. The knowledge of the mechanism of these reactions permits to establish the necessary conditions to achieve the desired phases in the final product. The mechanisms of the Carbonitriding reactions of several minerals with increasing aluminium content are studied. Their compositions are from diatomite up to mullite. Reactions of the mineral carbon mixture were carried out at 1300–1650°C in N 2 atmosphere. The phases formed were identified by X-ray diffraction in qualitative and, in some cases, in quantitative form. Intermediate compounds such as β -SiC, X-phase, mullite, glassy phases and gaseous silicon oxide were observed. The formation and importance of these phases depend on the mineral composition as well as on the reaction conditions (temperature, time, etc.). β -SiC, the main intermediate phase, may remain in the final products and may be the major phase depending on the temperature and the carbon content used. The final products of these reactions are phases of the Si–Al–O–N system. The phases obtained were characterized by EPMA, SEM and BET techniques.
Enrique Pereira - One of the best experts on this subject based on the ideXlab platform.
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Carbonitriding of clay relation between the weight loss and crystalline phases during reaction
Journal of the American Ceramic Society, 1993Co-Authors: Alfredo D Mazzoni, Esteba E Aglietti, Enrique PereiraAbstract:β'-Sialons are phases of the Si-Al-O-N system. The Carbonitriding of clays and kaolins is a preparation method. The reaction mechanism of clay Carbonitriding is verified by means of the relation among crystalline phases formed and the weight loss produced in the samples during the reaction. Two clays were previously mixed with carbon black and pressed into pellets, flowing through N2 atmosphere, at five temperatures within the range 1335–1427°C. The phases formed (XRD)—mullite, SiC, β′A-sialon, and oxynitrides—were related to the weight loss measured in the pellet independently of reaction temperature and time. The β′A-sialon and the nitrogenous phases were formed from SiC and mullite. A z value decrease for β′A-sialon was observed during reaction progression.