Fabrication and Characterization of a Feldspar-Alumina for Dental Ceramic

2010 ◽  
Vol 160-162 ◽  
pp. 424-427
Author(s):  
Guang Lei Zhang ◽  
Guo Qiang Qin ◽  
Yuan Hua Zhang ◽  
Pu Cheng ◽  
Chang Tao Shao

Feldspar-alumina dental ceramics were produced by impressed sintering method and characterized by X-ray diffraction and scanning electron microscope techniques. The machinability of the obtained alumina ceramics was evaluated by grinding capacity in the simulative grinding experiment. The results show that an appropriate amount of feldspar additive can reduce the sinter temperature and improve density, bending strength and machinability of alumina dental ceramics. Under 10 wt% feldspar and 1450 °C sinter temperature, the relative density and bending strength of ceramic reached 93.62% and 235MPa, respectively.

2017 ◽  
Vol 68 (4) ◽  
pp. 707-710
Author(s):  
Horia Manolea ◽  
Mirela Opri ◽  
Nicoleta Cioatera ◽  
Adriana Voinea ◽  
Radu Rica ◽  
...  

The aim of this study was to present and discuss the characteristics of three ceramic powders as well as the sintered material from the three commercial dental ceramics produced by Vita Zahnfabrik, Germany (VM13 and VMK Master, used for veneering metal frameworks, respectivelly VM9 used for veneering zirconia frameworks). An X-ray diffraction (XRD) analysis was performed, Raman spectra were recorded and the morphology of the samples was evidenced by using a high resolution scanning electron microscope, equipped with an EDXS detector. The results of this study corroborated with the presented literature data helps practitioners to better understand the interaction of these biomaterials with oral tissues, and, also helps researchers to modify the properties of ceramics for a better integration in the intraoral condition.


2017 ◽  
Vol 268 ◽  
pp. 311-314 ◽  
Author(s):  
M.A. Suazlina ◽  
H. Azhan ◽  
S. Akmal Syamsyir ◽  
K. Azman ◽  
W.A.W. Razali ◽  
...  

This paper reports the properties of Bi-2223 superconductors that had been doped with Fe2O3 at Cu-site of the system. It was prepared in bulk form using high purity oxide powders via solid state reaction technique with intermediate grinding. A series of x = 0.00, 0.02, 0.04, 0.06, 0.08 and 0.10 of Fe were stoichiometrically added to the well balanced of Bi1.6Pb0.4Sr2Ca2Cu3-xFexOy in order to trace the effect of Fe doping. Hence, electrical resistivity, X-ray diffraction and Field Emission Scanning Electron Microscopy have been carried out to assess the effects of Fe doping. These measurements indicate that Fe doping decreased the critical temperature and degrade the formation of high Tc phase compared with the undoped sample. The orthorhombicity parameters were increased due to substitution of Cu 3+ ion by Fe 2+ ion.


2018 ◽  
Vol 912 ◽  
pp. 159-164
Author(s):  
Rafael Bernardino da Silva Jr. ◽  
Claudinei dos Santos ◽  
Leonardo Queiroz Bueno de Campos ◽  
Sabrina Vieira Campos ◽  
Yan Carlos Ambrosio de Souza

In this work, dental ceramics based on ZrO2-Y2O3, made by cold isostatic pressing, were characterized and the properties were compared to conventional uniaxially pressed blocks. Pre-sintered ZrO2-3%mol Y2O3 blocks were sintered at 1530oC-120min. The crystalline phases were identified by X-ray diffraction (XRD) and microstructural analysis was performed using Scanning Electron Microscopy (SEM). The materials were mechanically evaluated for their hardness, fracture toughness and its bending strength. The results of mechanical tests indicate that the ceramics studied showed hardness greater than 1220HV, fracture toughness of about 8.2 MPam1/2 and bending strength higher than 1000 MPa. The results indicate excellent mechanical behaviour and negligible differences between uniaxial and isostatic products, but it is possible to see an increase of homogeneity in the final shrinkage after sintering.


2013 ◽  
Vol 641-642 ◽  
pp. 410-413
Author(s):  
Chao Wang ◽  
Jian Zhang ◽  
Xiang Xin Xue ◽  
Xiao Zhou Cao

In this paper, B-Ni-Al shield materials were fabricated by vacuum metal infiltration. The B-Ni-Al Composite were fabricated by preheating BN+Ni at 1550°C for one hour before infiltrating Al alloys into the preforms in a vacuum at 1100°C for two hours. Microstructural characterization of the materials obtained was performed using X-ray diffraction, scanning electron microscopy(SEM). Mechanical properties were evaluated by fracture toughness and bending strength. AlN was produced with interfacial reactions between Al and BN.


Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


2012 ◽  
Vol 620 ◽  
pp. 314-319
Author(s):  
Nur Amira Mamat Razali ◽  
Fauziah Abdul Aziz ◽  
Saadah Abdul Rahman

Hardwood is wood from angiosperm trees. The characteristic of hardwood include flowers, endosperm within seeds and the production of fruits that contain the seeds. This paper aims to discuss the preparation and characterization of cellulose obtained from hardwood. The hardwood Merbau (Intsia bijuga) was chosen as raw material in this study. Alkaline treatment and delignification methods were used for the preparation of cellulose. Acid hydrolysis was employed to produce cellulose nanocrystal (CNC). The treated and untreated samples were characterized using x-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The final product, from both trated and untreated samples were then compared.


2012 ◽  
Vol 174-177 ◽  
pp. 508-511
Author(s):  
Lin Lin Yang ◽  
Yong Gang Wang ◽  
Yu Jiang Wang ◽  
Xiao Feng Wang

BiFeO3 polyhedrons had been successfully synthesized via a hydrothermal method. The as-prepared products were characterized by power X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The possible mechanisms for the formation of BiFeO3 polyhedrons were discussed. Though comparison experiments, it was found that the kind of precursor played a key role on the morphology control of BiFeO3 crystals.


1989 ◽  
Vol 4 (6) ◽  
pp. 1320-1325 ◽  
Author(s):  
Q. X. Jia ◽  
W. A. Anderson

Effects of hydrofluoric acid (HF) treatment on the properties of Y–Ba–Cu–O oxides were investigated. No obvious etching of bulk Y–Ba–Cu–O and no degradation of zero resistance temperature were observed even though the oxides were placed into 49% HF solution for up to 20 h. Surface passivation of Y–Ba–Cu–O due to HF immersion was verified by subsequent immersion of Y–Ba–Cu–O in water. A thin layer of amorphous fluoride formed on the surface of the Y–Ba–Cu–O during HF treatment, which limited further reaction between Y–Ba–Cu–O and HF, and later reaction with water. Thin film Y–Ba–Cu–O was passivated by HF vapors and showed no degradation in Tc-zero after 30 min immersion in water. The properties of the surface layer of Y–Ba–Cu–O oxide after HF treatment are reported from Auger electron spectroscopy, x-ray diffraction, and scanning electron microscopy studies.


2021 ◽  
pp. 004051752110154
Author(s):  
Zhihui Qin ◽  
Shuyuan Zhao ◽  
Liu Liu ◽  
Zhaohe Shi ◽  
Longdi Cheng ◽  
...  

Degumming is the dominant method for insolating lignocellulosic fibers in textile applications. Traditional alkaline degumming (TAL), as a common method, requires a high-concentration alkali and has been a severe challenge to the environment. In the research reported here, the possibility of innovative jute degumming by organic solvents 1-2 propylene glycol and a combination of additive green oxygen (GO-OS) was studied. The results revealed that fibers could be extracted by this system (under condition of 0.9% GO-OS, 180°C, 120 min), and obtained fibers with higher breaking tenacity (7.1 cN/dtex), yield (65.7%), breaking elongation (2.87%) and residual gum (11.7%), which all meet the requirement of the relevant Chinese Textile National Standards. Notably, the required reaction time (120 min) of the GO-OS system was 180 min shorter than that of the TAL method. Furthermore, the modifications introduced by the degumming effect on physicochemical aspects were characterized and confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction. This study provides a promising degumming method for separating jute lignocellulose without acid and alkali consumption.


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