Forensic Analysis of Disintegrated Grinding Wheels using the Sem and X-Ray Microanalysis

1976 ◽  
Vol 34 ◽  
pp. 392-393
Author(s):  
John L. Brown
Keyword(s):  
Silicon Carbide ◽  
Aluminum Oxide ◽  
Porous Structure ◽  
Forensic Analysis ◽  
Grinding Wheels ◽  
Fabric Reinforcement ◽  
X Ray ◽  
Abrasive Grains ◽  
High Speeds ◽  
Ceramic Process

Grinding is a microscopic chipping process for removing material from metal or other hard surfaces. This is commonly accomplished by a rotating wheel consisting of abrasive grains bonded into place with a resin or ceramic material. Aluminum oxide and silicon carbide are the usual abrasives. The most frequently used bond is a vitrified composition of feldspars and clays fired in a ceramic process along with a desired mixture of abrasives. This type of wheel is very hard and easily subject to damage and is normally used in a stationary grinding position. For portable hand-held grinding a resin bonded wheel is used. Resinoid wheels have a more porous structure than vitreous wheels and can be used at high speeds for cool cutting. Frequently fabric reinforcement is used within the structure of the wheel, and it may be operated at higher RPM than other types of wheels.

The Characterization of Defects in Silicon Carbide Crystals by X-Ray Topography in the Back-Reflection Geometry

2004 ◽  
Vol 230-232 ◽  
pp. 1-16 ◽  
Author(s):  
William M. Vetter
Keyword(s):  
Silicon Carbide ◽  
Computer Algorithms ◽  
Reflection Mode ◽  
X Ray ◽  
Back Reflection ◽  
Device Structures ◽  
Reflection Geometry ◽  
Grade Silicon ◽  
Favorable Conditions

Synchrotron white-beam x-ray topographs taken in the back-reflection mode have proved a powerful tool in the study of defects in semiconductor-grade silicon carbide crystals. Capable of mapping the distribution of axial dislocations across a wafer's area (notably the devastating micropipe defect), it can also provide information on their natures. Under favorable conditions, various other types of defect may be observed in back-reflection topographs of SiC, among which are subgrain boundaries, inclusions, and basal plane dislocations. Observed defect images in backreflection topographs may be simulated using relatively simple computer algorithms based on ray tracing. It has been possible to use back-reflection topographs of SiC substrates with device structures deposited upon them to relate the incidence of defects to device failure.

Development of 3D Printing Technology with Ceramic Paste and Study of Properties of Printed Corundum Products

2021 ◽  
Vol 1040 ◽  
pp. 178-184
Author(s):  
Andrey S. Dolgin ◽  
Aleksei I. Makogon ◽  
Sergey P. Bogdanov
Keyword(s):  
3D Printing ◽  
Aluminum Oxide ◽  
Reference Sample ◽  
Physical And Mechanical Properties ◽  
Ceramic Technology ◽  
Raw Material ◽  
Energy Costs ◽  
Additive Technology ◽  
X Ray ◽  
Manufacturing Time

Today 3D printing with ceramics is a promising direction in the development of additive technologies. In this work, we have developed a technology for printing with ceramic pastes based on aluminum oxide and wax, namely: an extruder for printing with ceramic pastes was modeled and manufactured, the composition of the slip was selected and the paste for printing was made. After choosing the print parameters, test samples were printed: a disk and a box. Since 3D printing with ceramics is just one of the stages of manufacturing ceramic products, then we selected the parameters for drying and sintering the raw material. Drying of products is necessary to burn off an excess amount of a binder (paraffin), and due to sintering; the raw material acquires final strength and mechanical characteristics. After sintering, the sintering parameters and physical and mechanical properties of the products were measured. The microstructure of the printed products was studied using scanning electron microscopy. The phase change during sintering was studied by X-ray analysis. All obtained properties were compared with a reference sample (corundum tile made of aluminum oxide of the same grade, but using traditional ceramic technology, including pressing, drying and sintering of the product). In terms of all properties, the printed ceramics are not significantly inferior to the reference sample; however, in general, the additive technology has more advantages, such as a wide variety of shapes, shorter manufacturing time for parts, and lower energy costs.

Embedding Cs 3 Cu 2 I 5 Scintillators into Anodic Aluminum Oxide Matrix for High‐Resolution X‐Ray Imaging

2021 ◽  
pp. 2101194
Author(s):  
Xue Zhao ◽  
Tong Jin ◽  
Wanru Gao ◽  
Guangda Niu ◽  
Jinsong Zhu ◽  
...  
Keyword(s):  
High Resolution ◽  
Aluminum Oxide ◽  
Anodic Aluminum Oxide ◽  
X Ray ◽  
Anodic Aluminum ◽  
X Ray Imaging ◽  
Oxide Matrix

Template Synthesis of Indium Nanowires Using Anodic Aluminum Oxide Membranes

2008 ◽  
Vol 8 (9) ◽  
pp. 4488-4493 ◽  
Author(s):  
Feng Chen ◽  
Adrian H. Kitai
Keyword(s):  
Aluminum Oxide ◽  
Template Synthesis ◽  
Anodic Aluminum Oxide ◽  
Preferred Orientation ◽  
Hydraulic Pressure ◽  
X Ray Diffraction ◽  
Aao Template ◽  
X Ray ◽  
Anodic Aluminum ◽  
Oxide Membranes

Indium nanowires with diameters approximately 300 nm have been synthesized by a hydraulic pressure technique using anodic aluminum oxide (AAO) templates. The indium melt is injected into the AAO template and solidified to form nanostructures. The nanowires are dense, continuous and uniformly run through the entire ∼60 μm thickness of the AAO template. X-ray diffraction (XRD) reveals that the nanowires are polycrystalline with a preferred orientation. SEM is performed to characterize the morphology of the nanowires.

Silicon oxycarbide glasses: Part II. Structure and properties

1991 ◽  
Vol 6 (12) ◽  
pp. 2723-2734 ◽  
Author(s):  
Gary M. Renlund ◽  
Svante Prochazka ◽  
Robert H. Doremus
Keyword(s):  
Silicon Carbide ◽  
Coefficient Of Thermal Expansion ◽  
Random Network ◽  
Silicon Oxycarbide ◽  
Index Of Refraction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Silicon Oxycarbide Glasses ◽  
Oxycarbide Glass ◽  
Silicon Oxygen

Silicon oxycarbide glass is formed by the pyrolysis of silicone resins and contains only silicon, oxygen, and carbon. The glass remains amorphous in x-ray diffraction to 1400 °C and shows no features in transmission electron micrographs (TEM) after heating to this temperature. After heating at higher temperature (1500–1650 °C) silicon carbide lines develop in x-ray diffraction, and fine crystalline regions of silicon carbide and graphite are found in TEM and electron diffraction. XPS shows that silicon-oxygen bonds in the glass are similar to those in amorphous and crystalline silicates; some silicons are bonded to both oxygen and carbon. Carbon is bonded to either silicon or carbon; there are no carbon-oxygen bonds in the glass. Infrared spectra are consistent with these conclusions and show silicon-oxygen and silicon-carbon vibrations, but none from carbon-oxygen bonds. 29Si-NMR shows evidence for four different bonding groups around silicon. The silicon oxycarbide structure deduced from these results is a random network of silicon-oxygen tetrahedra, with some silicons bonded to one or two carbons substituted for oxygen; these carbons are in turn tetrahedrally bonded to other silicon atoms. There are very small regions of carbon-carbon bonds only, which are not bonded in the network. This “free” carbon colors the glass black. When the glass is heated above 1400 °C this network composite rearranges in tiny regions to graphite and silicon carbide crystals. The density, coefficient of thermal expansion, hardness, elastic modulus, index of refraction, and viscosity of the silicon oxycarbide glasses are all somewhat higher than these properties in vitreous silica, probably because the silicon-carbide bonds in the network of the oxycarbide lead to a tighter, more closely packed structure. The oxycarbide glass is highly stable to temperatures up to 1600 °C and higher, because oxygen and water diffuse slowly in it.

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