Effects of Deposition Temperature on the Growth Characteristics of CVD SiC Coatings

2008 ◽  
Vol 368-372 ◽  
pp. 846-848 ◽  
Author(s):  
Yan Li Huo ◽  
Yu Feng Chen
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Phase Composition ◽  
Crystallite Size ◽  
Deposition Temperature ◽  
Optical Microscope ◽  
Columnar Structure ◽  
Growth Characteristics ◽  
Sic Coatings

The effects of deposition temperature on the growth characteristics of CVD SiC coatings were investigated. CVD SiC coatings were made by pyrolysis of methyltrichlorosilane (MTS) in hydrogen at a low pressure of 5kPa. The ratio of MTS to hydrogen was 1/12. The deposition temperatures were varied from 1373K to 1503K. Optical microscope and SEM were used to observe the surface morphology and microstructure of the coatings. XRD was used for characterization of the phase composition. Results indicated that the deposition rate and the surface roughness varied with deposition temperature. At 1373K, the deposited grains were mainly equiaxed with the crystallite size of 22 nm. However, when the deposition temperature was 1503K, the SiC grains were mainly showed faceted columnar structure with the crystallite size of 32 nm. Grain size increased with the increase of deposition temperature.

Grain Structure and Surface Roughness of Four Commercial NiTi Orthodontic Archwires

2017 ◽  
Vol 266 ◽  
pp. 257-263
Author(s):  
Wassana Wichai ◽  
Rutchadakorn Isarapatanapong ◽  
Niwat Anuwongnukroh ◽  
Surachai Dechkunakorn
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Optical Microscope ◽  
Grain Structure ◽  
Wire Surface ◽  
Average Grain Size ◽  
Electron Mode ◽  
The Mean ◽  
The Wire ◽  
Orthodontic Archwires

This study investigated four commercially available NiTi orthodontic archwires from different manufactures for their grain structure and surface roughness.Four commercially available pre-formed NiTi orthodontic archwire (Ormco, Sentalloy, Highland and NIC) with diameter 0.016 x 0.022 inch2 were tested. The wire samples were polished and etched to evaluate the morphology and structure of wire surface. Each NiTi archwire was investigated under a reflected light microscope of an Optical Microscope to analyze its grain structure and size, in longitudinal surfaces. The surfaces of wire were qualitatively examined in the secondary electron mode at common magnification (500X). The surface roughness was also evaluated by a surface roughness tester. The descriptive statistic was evaluated the mean and standard deviation of surface roughness and Medcale T-Test was to test the mean difference of the surface roughness in each brands. This study showed an average grain size of 2-8 μm for each NiTi archwire. The wire surface of Ormco and Highland showed straiations along the longitudinal axes, however Sentalloy and NIC showed small pores on the wire surface. The surface roughness was 0.09 μm for Highland, 0.25 μm for Sentalloy, 0.28 μm for Ormco and 0.46 μm for NIC archwire. The Highland was smoothest and NIC was the roughest. There were in significant (p < 0.05) difference of surface roughness of each brands. The results showed that the four manufactures NiTi archwires were different in grain size, wire surface and surface roughness. During clinical application, these archwires may exhibit different mechanical properties, such as strength, hardness, ductity, and friction because of their microstructure.

Characterization of processing pores and their relevance to the strength in alumina ceramics

1999 ◽  
Vol 14 (8) ◽  
pp. 3370-3374 ◽  
Author(s):  
Yao Zhang ◽  
Mineyuki Inoue ◽  
Nozomu Uchida ◽  
Keizo Uematsu
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Power Function ◽  
Optical Microscope ◽  
Strength Distribution ◽  
Alumina Ceramics ◽  
Simple Power Function ◽  
Measured Strength ◽  
Good Agreement

Characterization of bulk defects was successfully accomplished in alumina with a transmission optical microscope. The characterization technique used is based on the fact that many ceramics are essentially transparent. Most defects in this particular ceramic were found to be pore. Their size distribution was found to follow a simple power function. With these characteristics of defects, the strength distribution of the ceramics was calculated with Baratta's model and compared to the measured strength of the ceramics. A good agreement was found between them when the pore was assumed to be accompanied with cracks 4 times the length of the grain size.

Characterization of Stress and Texture in Rtcvd Poly-Si Layers by X-Ray Diffraction

1991 ◽  
Vol 239 ◽  
Author(s):  
István Bársony ◽  
Jos G.E. Klappe ◽  
Tom W. Ryan
Keyword(s):  
Deposition Temperature ◽  
Polycrystalline Silicon ◽  
Columnar Structure ◽  
Film Stress ◽  
Grain Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Residual Film ◽  
Post Deposition

ABSTRACTThe properties of polycrystalline silicon layers deposited by RTCVD have been studied by texture, stress and electrical analyse. The intrinsic layers intended for applications in integrated IC processing are very much textured with the preferred orientation depending on deposition temperature and atmosphere. Very low residual film stress in the order of 10 dyn/cm2 was detected, and a transition from compressive to tensile stress with increasing deposition temperature around 800°C was observed. This was associated with the development of the columnar structure by the (110) orientation becoming dominant at the expense of the (100) texture. Also the effect of post-deposition anneal ambience on the grain structure has been studied. Grain size and grain-boundary trapping in after doped layers have been evaluated in P-implanted RTA activated layers.

Structural Characterization of Reactive DC Magnetron Co-Sputtered Nanocrystalline CrAlN Thin Film

2017 ◽  
Vol 751 ◽  
pp. 84-87
Author(s):  
Amonrat Khambun ◽  
Adisorn Buranawong ◽  
Nirun Witit-Anun
Keyword(s):  
Thin Films ◽  
Chemical Composition ◽  
Crystallite Size ◽  
Deposition Time ◽  
Columnar Structure ◽  
Silicon Substrates ◽  
Lattice Constants ◽  
Film Hardness ◽  
Deposited Films

Nanocrystalline CrAlN thin films were deposited on silicon substrates by reactive DC magnetron co-sputtering technique. The effect of deposition time on crystal structure, chemical composition, thickness, microstructure and hardness of the thin films were characterized by XRD, EDS, AFM and FE-SEM and Nanoindentation, respectively. The as-deposited films were formed as a (Cr,Al)N solid solution with (111), (200) and (220) plane. The lattice constants were in range of 3.9916 - 4.0455 Å. The as-deposited films exhibited a nanostructure with a crystallite size in range of 15-35 nm. The thickness and roughness increased from 197 nm to 998 nm and 1.6 nm to 8.1 nm, respectively, with increasing the deposition time. The chemical composition of the films varied with the deposition time. The cross section analysis by FE-SEM showed columnar structure and dense morphology. The film hardness decreased from 39 GPa to 25 GPa with increasing the deposition time and crystallite size.

Effects of Deformation and Annealing Temperature on the Microstructures and Hardness of Cu-29Zn-0.6Bi Brass

2017 ◽  
Vol 748 ◽  
pp. 218-223 ◽  
Author(s):  
Imam Basori ◽  
Ruther Gadhu ◽  
Bondan Tiara Sofyan
Keyword(s):  
Grain Size ◽  
Hardness Measurement ◽  
Optical Microscope ◽  
Annealing Process ◽  
Gravity Casting ◽  
Slip Mechanism ◽  
Cold Rolled ◽  
Negative Impacts ◽  
Characterization Of Materials

The use of lead-free brass is growing due to the restriction of the lead content in many components. Bismuth replaces lead in the brass alloys and contributes to the machinability and pressure tightness characteristics. However, Bi is immiscible in copper and fills the inter-dendritic spaces during solidication that yields negative impacts on the mechanical properties. This research studied the effects of addition of 0.6 wt. % Bi on the characteristics of Cu-29Zn alloy during cold rolling and subsequent annealing process. The Cu-29Zn-0.6wt.%Bi alloy was produced by gravity casting in a metal mold with the dimension of 110x110x6 mm3. The as-cast plate was homogenized at 800 °C for 2 hours and then cold rolled with the level of deformation of 20, 40 and 70 % in multiple passes. The samples with 70% deformation was annealed at 350, 400 and 450 °C for 15 minutes. Characterization of materials included Vickers hardness measurement and microstructural observation by using optical microscope and SEM. The results showed that addition of Bi reduced the grain size, formed discrete globules in the interdendritic areas and increased the hardness. The globules as dispersoid bismuth deformed and filled intergranular spaces during rolling and promoted the formation of cross slip mechanism at the 20% deformation. At the 40% deformation, the globules led to more closely spaced twin lamellae and increased the twinning density. The phenomena created an inhomogeneous deformation and promoted the formation of shear band. Annealing process dispersed the Bi globules into tight structures along the grain boundaries.The presence of dispersed bismuth increased the rate of recrystallization during annealing due to the increased in potential site for nucleation. In contrast, the dispersed bismuth acted as the pinning agent that inhibited the grain growth and developed smaller grain size which resulted in higher hardness.

scholarly journals Structure and morphology of nano-sized W-Ti/Si thin films

2006 ◽  
Vol 71 (8-9) ◽  
pp. 969-976 ◽  
Author(s):  
Suzana Petrovic ◽  
Borivoje Adnadjevic ◽  
Davor Perusko ◽  
Nada Popovic ◽  
Nenad Bundaleski ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Surface Roughness ◽  
Grain Size ◽  
Phase Composition ◽  
Surface Segregation ◽  
Morphological Characteristics ◽  
Film Surface ◽  
Scanning Tunneling ◽  
Tunneling Microscopy

Thin films were deposited by d.c. sputtering onto a silicon substrate. The influence of the W-Ti thin film thickness to its structural and morphological characteristics of a nano-scale were studied. The phase composition and grain size were studied by X-ray diffraction (XRD), while the surface morphology and surface roughness were determined by scanning tunneling microscopy (STM). The analysis of the phase composition show that the thin films had a polycrystalline structure - they were composed of a b.c.c. W phase with the presence of a h.c.p. Ti phase. The XRD peak in the scattering angle interval of 38?-43? was interpreted as an overlap of peaks corresponding to the W(110) and Ti(101) planes. The grain size and the mean surface roughness both increase with the thikness of the thin film. The chemical composition of the thin film surface was also analyzed by low energy ions scattering (LEIS). The results show the surface segregation of titanium, as well as a substantial presence of oxygen an the surface.

Structural Evolution of Nanocrystalline Germanium Thin Films with Film Thickness and Substrate Temperature

2003 ◽  
Vol 762 ◽  
Author(s):  
William B. Jordan ◽  
Eric D. Carlson ◽  
Todd R. Johnson ◽  
Sigurd Wagner
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Grain Size ◽  
Film Thickness ◽  
Vapor Deposition ◽  
Deposition Temperature ◽  
Structural Evolution ◽  
Chemical Vapor ◽  
Force Microscopy ◽  
Atomic Force

AbstractThe structure of germanium thin films prepared on glass by plasma enhanced chemical vapor deposition was characterized by Raman spectroscopy, atomic force microscopy (AFM) and field emission scanning electron microscopy (SEM). Crystallinity, surface roughness, and grain size were measured as functions of film thickness and deposition temperature. Grain nucleation was apparent for films as thin as 10 nm. Over the thickness range studied, grain size increased with film thickness, whereas average surface roughness started to increase with film thickness, but then remained fairly constant at approximately 1 nm for a film thickness greater than 25 nm.

scholarly journals Laboratory Characterization of In-Service Full-Mouth Rehabilitation with Monolithic Translucent Zirconia Restorations

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1755
Author(s):  
Susana M. Salazar Marocho ◽  
Mary Beth VanLandingham ◽  
Firas Mourad ◽  
Andres Pappa ◽  
Sreenivas Koka
Keyword(s):  
Surface Roughness ◽  
Surface Damage ◽  
Optical Microscope ◽  
Posterior Teeth ◽  
Golden Proportion ◽  
Laboratory Characterization ◽  
Full Mouth Rehabilitation ◽  
Zirconia Crowns

The chance to critically and microscopically inspect the quality of bonded restorations once they are delivered to the patient after several pre-cementation steps is rare or nonexistent. Replicas of in-service restorations can provide a wealth of information on the integrity of the restorations and moreover make it possible to bring this information to the laboratory for further detailed analysis. This study aimed to characterize the epoxy replicas of 27 cemented monolithic yttria-stabilized zirconia crowns of the maxillary and mandibular arch to assess surface roughness, topography, and symmetry. The topography of the facial, lingual, and occlusal/incisal surfaces of each crown was observed under the optical microscope and further characterized using the scanning electron microscope. Surface roughness measurements were performed using the atomic force microscope. The optical microscope was used to measure the golden proportion and visible width of the anterior maxillary crowns. Surface damage consistent with unpolished adjustment was identified mostly in the occlusal surface of the posterior teeth. Other irregularities, such as scratch marks, small pits, and coarse pits were also found. The surface roughness had great variability. Not all of the anterior maxillary and mandibular teeth followed the golden proportion concept. This study design allows in vitro characterization of in-service restorations. It provides a framework for using replicas for early identification of patterns or features that can trigger fracture and for analysis of morphology and symmetry.

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