Interface Reaction between Directional Solidified Superalloy DZ40M and Ceramic Mould

2021 ◽  
Vol 1035 ◽  
pp. 235-242
Author(s):  
Li Li Wang ◽  
Jian Sheng Yao ◽  
Guo Hong Gu ◽  
Xin Li ◽  
Shu Xin Niu ◽  
...  

The interfaces between DZ40M directional solidified superalloy and ceramic mould (SiO2-base core and Al2O3-base shell) was studied by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results showed that there was a serious interface reaction between DZ40M and ceramic cores,which resulted in many reaction pits (~100μm deep), Si rich residue alloys and Zr rich subglobose oxides on the inner surface. And the interface reaction between DZ40M and ceramic shell induced a ~50μm of pink sand burning layer. The thermal analysis showed that the reactions between DZ40M and core or shell were similar: the active alloy constituents (Zr, Al, Ti and Cr) were oxidized and became oxides or solid solution with the core or shell components (SiO2, Al2O3 or Fe2O3), but the interface characterization of DZ40M/core and DZ40M/shell was different because the shell had the main content of Al2O3 and impurity of Fe2O3, while those of the core were SiO2 and CaO, respectively.

1997 ◽  
Vol 12 (12) ◽  
pp. 3206-3209 ◽  
Author(s):  
V. Oliveira ◽  
R. Vilar ◽  
O. Conde ◽  
P. Freitas

Al2O3−34 wt.% TiC ceramics have been machined with a KrF (248 nm) excimer laser under normal atmosphere. In the initial steps of the irradiation process both the roughness and the removal rate present a strong variation with the number of pulses. After approximately 200 pulses the process reaches a stationary regime where the roughness and the removal rate become constant. Characterization of the machined areas by scanning electron microscopy showed that the variations in roughness and removal rate are related to the evolution of the surface topography of the samples. Also, as a consequence of laser irradiation, TiC and Al2O3 are partially transformed into TiO2, TiC0.7N0.3, and an Al–Ti solid solution.


2000 ◽  
Vol 55 (9) ◽  
pp. 882-886 ◽  
Author(s):  
Martin Jansen ◽  
Sascha Vensky

The silver(I,II,III) oxide clathrate Ag7O8HCO3 was synthesized by anodic oxidation of silver(I) in a suspension of Ag2CO3 in an aqueous AgF solution. The title compound was characterized by single crystal X-ray diffraction (cubic, Fm3̄m, a = 9.8085(3) Å, Z = 4), scanning electron microscopy, thermal analysis, IR spectroscopy, 1H-solid state-NMR and measurement of the magnetic susceptibility


2014 ◽  
Vol 975 ◽  
pp. 233-237
Author(s):  
Joelma C. S. Breve ◽  
Dayse I. dos Santos

Nanostructured composites based on titanium dioxide have been studied in order to improve optical and photo-catalytic properties, as well as their performance in gas sensors. In this work, titanium and tin dioxides were simultaneously synthesized by the polyol method resulting in TiO2 platelet coated with SnO2 nanoparticles as was observed by scanning electron microscopy. The thermal analysis showed that the combined synthesis promotes more easily the crystallization of the TiO2 rutile phase. The composite obtained after heat treatment at 500 °C showed to be formed of almost only rutile phases of both oxides. The optical properties analyzed by UV-Vis spectroscopy showed that the combined oxides have higher absorbance, which reinforces a model found in the literature based on the flow of photo-generated electrons to the conduction band of SnO2 delaying the recombination of charges.


2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Gordana Оstojić ◽  
Dragica Lazić ◽  
Branko Škundrić ◽  
Jelena Penavin Škundrić ◽  
Slavica Sladojević ◽  
...  

From the aspect of their chemical and mineralogical composition, bauxites are very complex multicomponent raw materials. The paper presents the characterization of bauxite from several different deposits: Brazil, Milići, Čitluk and Kosovo. Chemical characteristics were determined by a combination of different analytical methods: gravimetry, potentiometric titration, atomic absorption spectroscopy (AAS) and UV-VIS spectrophotometry. Mineralogical composition was determined using X-ray diffraction and thermal analysis methods. Chemical and structural characterization is complemented by the results of scanning electron microscopy with EDX analysis. The information obtained was used for the assessment of the quality of investigated bauxites from the aspect of their application in the production of alumina.


2014 ◽  
Vol 809-810 ◽  
pp. 313-318
Author(s):  
Peng Cheng Song ◽  
Tong Jiang Peng ◽  
Hong Juan Sun ◽  
Yu Cao Yu

Fibri-form silica was extracted from short chrysotile fibers by mix-roasting with ammonium bisulfate. The fibri-form silica were characterized by X-ray fluorescence analysis (XRF), X-ray diffraction (XRD), thermogravimetry and differential thermal analysis (TG-DTA), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FT-IR) and N2 adsorption isotherms. The results show that the fibri-form silica with disordered crystalline structure, but also in fibrous morphology. The surface area and pore volume of fibri-form silica are 181.66 m2/ g and 0.44 cc/ g, respectively. The structure of fibri-form silica is stable, no phase transformed from 50 to 1200 oC.


2008 ◽  
Vol 587-588 ◽  
pp. 458-462 ◽  
Author(s):  
Ivana Cesarino ◽  
Éder T.G. Cavalheiro ◽  
Glimaldo Marino ◽  
Jivaldo R. Matos

Mesoporous silica can be modified and functionalised by immobilisation of organic substances covalently bonded to the silanol groups on the silica surface. This paper describes the modification of a SBA-15 nanostructured silica with 2-benzothiazolethiol. After derivatization the modified silica was chacacterized by elemental analysis, IR spectroscopy, thermal analysis (TG and DSC), NMR in solid phase and scanning electron microscopy.


2007 ◽  
Vol 333 ◽  
pp. 289-292
Author(s):  
Măriuca Gartner ◽  
M. Crisan ◽  
L. Predoana ◽  
Maria Zaharescu ◽  
A. Barau ◽  
...  

In this work, we report the sol-gel alkoxide route preparation of nanostructured SiO2 and TiO2 powders as well as TiO2-SiO2 thin films obtained by dip-coating. Thermal analysis, morphology and structure were characterized for powders and correlation between preparation method and optical properties of binary materials (SiO2-TiO2) for thin films was approached. Spectroscopic Ellipsometry (SE), Fourier Transform Infrared Spectroscopy (FTIR) and scanning electron microscopy (SEM) have been used for the physical characterization of the films.


2017 ◽  
Vol 1142 ◽  
pp. 14-18 ◽  
Author(s):  
Shi Qian Zhao ◽  
Lei Ma ◽  
Liang Zhou ◽  
Tao Liu ◽  
Yong Bin Guo

The crystal structure of GdFeMn alloy has been investigated by using X-ray powder diffraction (XRD) followed by Rietveld refinement technique, differential thermal analysis (DTA) and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) techniques. XRD results showed that annealed GdFeMn alloy was a single phase of Gd6(Fe0.5Mn0.5)23 compound, with Th6Mn23-structure. SEM/EDS results and Rietveld refinement revealed that GdFeMn alloy was not really a new ternary compound as reported, but a solid solution Gd6(Fe0.5Mn0.5)23 which was only a point between Gd6Fe23 and Gd6Mn23. It was also found from DTA measurement that a reaction, Gd (Fe0.5Mn0.5)2 → liquid (rich Gd) + Gd6(Fe0.5Mn0.5)23, had taken place above 650.81 oC, and the educed Gd existed in educed part of GdFeMn sample. The results demonstrated the real structure of the GdFeMn compound as reported was Gd6(Fe0.5Mn0.5)23 compound.


1997 ◽  
Vol 3 (S2) ◽  
pp. 787-788
Author(s):  
P. Sarin ◽  
W.M. Kriven ◽  
V.L. Snoeyink

Corrosion of cast iron (C.I.) pipe often results in the formation of “tubercles” on the inner surface of the pipe. Tubercles are layered deposits formed by the stacking of several layers of corrosion products one on top of the other (Fig.l). Tubercles not only increase the amount of energy required for transport of water but are also considered the main source of turbidity in potable water. Their chemical and physical characteristics are important factors which affect the release of iron into the bulk water.Tubercles are extremely complex systems. They may be highly crystalline in nature, with iron occurring in chemical structures, such as siderite (FeCO3), goethite (α-FeOOH), magnetite (Fe3O4) and lepidocrocite (γ-FeOOH) or they may be highly amorphous. Tubercles vary in height from a few millimeters to a few centimeters. They exhibit distinct layers which are formed over varying periods of time ranging from a few months to a century.


Sign in / Sign up

Export Citation Format

Share Document