Anisotropy of Surface Roughness on Aluminium Sheet Studied by Atomic Force Microscopy

2000 ◽  
Vol 6 (2) ◽  
pp. 137-144 ◽  
Author(s):  
George W. Ryan

Atomic force microscope images of aluminium sheet are used to calculate the mean roughness Ra and the root mean square roughness Rq for different directions ([theta]) across the samples. The angle determined values of Ra([theta] and Rq([theta]) are significantly lower in the rolling direction than in any other direction. The results provide a clear demonstration of the vector nature of surface roughness. Local features in an angle determined Rq([theta]) profile are also compared with the positions of peaks and valleys in the matching topographical crosssection of the surface running at right angles to [theta]. It is further found that the distribution of z heights for an imaged sample is usually not Gaussian in shape unless the z heights are measured about mean lines constructed across the surface parallel with the rolling direction. The results are relevant for controlling lubrication performance in the aluminium rolling process.

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 900
Author(s):  
Maria Vardaki ◽  
Aida Pantazi ◽  
Ioana Demetrescu ◽  
Marius Enachescu

In this work we present the results of a functional properties assessment via Atomic Force Microscopy (AFM)-based surface morphology, surface roughness, nano-scratch tests and adhesion force maps of TiZr-based nanotubular structures. The nanostructures have been electrochemically prepared in a glycerin + 15 vol.% H2O + 0.2 M NH4F electrolyte. The AFM topography images confirmed the successful preparation of the nanotubular coatings. The Root Mean Square (RMS) and average (Ra) roughness parameters increased after anodizing, while the mean adhesion force value decreased. The prepared nanocoatings exhibited a smaller mean scratch hardness value compared to the un-coated TiZr. However, the mean hardness (H) values of the coatings highlight their potential in having reliable mechanical resistances, which along with the significant increase of the surface roughness parameters, which could help in improving the osseointegration, and also with the important decrease of the mean adhesion force, which could lead to a reduction in bacterial adhesion, are providing the nanostructures with a great potential to be used as a better alternative for Ti implants in dentistry.


Author(s):  
C. Mathew Mate ◽  
Robert W. Carpick

When two surfaces are brought into contact, they first touch where the summits of the surface asperities make contact. Consequently, surface roughness or topography strongly influences those physical phenomena associated with contact: friction, adhesion, and wear. This chapter discusses techniques for measuring the roughness of surfaces and the parameters frequently used to characterize this roughness. As atomic force microscopy (AFM) and optical interferometry are currently the predominant tools for characterizing roughness, these techniques are discussed at some length. Examples are given for determining not only the standard roughness parameters (the standard deviation of surface heights, the mean radius of curvature of asperity summits, waviness, and the average and rms of surface heights), but also for determining the surface roughness power spectrum, which has gained importance in recent tribology theories. The topography of self-affine fractal surfaces is also discussed along with the tribological importance of these surfaces.


2019 ◽  
Vol 9 ◽  
pp. 223-229
Author(s):  
Faeze Qabel ◽  
Riehane Talaei ◽  
Saeedeh Saeedi ◽  
Raheb Ghorbani ◽  
Nazila Ameli

Purpose: Porcelain polishing after orthodontic bracket debonding and resin removal is imperative to eliminate surface roughness and minimize the risk of plaque accumulation, periodontal disease, and porcelain discoloration. This study aimed to assess the effect of three polishing systems on porcelain surface roughness after orthodontic bracket debonding. Materials and Methods: Thirty porcelain blocks were divided into three groups. Surface roughness of the samples was first measured using atomic force microscopy (AFM) and recorded as baseline. Orthodontic brackets were bonded to blocks by composite resin. After bracket debonding, resin remnants were removed by tungsten carbide bur. The blocks were then polished with Sof-Lex discs, Meisinger, and Jota porcelain polishing kit. Surface roughness was measured again using AFM. The Shapiro–Wilk test, one-way ANOVA, and Tukey’s post hoc test were used for data analysis through SPSS version 18.0. Level of significance was set at 5%. Results: The mean change in surface roughness after polishing with Jota kit (56.6 nm) was significantly greater than that compared to Sof-Lex discs (10.7 nm) (P = 0.003) and Meisinger kit (26.6 nm) (P = 0.024). The mean change in surface roughness was not significantly different between Sof-Lex and Meisinger groups. Surface roughness significantly increased in all three groups (P < 0.05). Conclusion: Meisinger polishing kit and Sof-Lex discs were not significantly different in terms of the resultant surface roughness. Thus, the conventional use of Sof-Lex discs seems to be more cost-effective due to their lower cost.


2010 ◽  
Vol 16 (5) ◽  
pp. 531-536 ◽  
Author(s):  
Verónica Zavala-Alonso ◽  
Gabriel A. Martínez-Castanon ◽  
Nuria Patiño-Marín ◽  
Humberto Terrones ◽  
Kenneth Anusavice ◽  
...  

AbstractThe aim was to characterize the external structure, roughness, and absolute depth profile (ADP) of fluorotic enamel compared with healthy enamel. Eighty extracted human molars were classified into four groups [TFI: 0, control (C); 1–3, mild (MI); 4–5, moderate (MO); 6–9, severe fluorosis (S)] according to the Thylstrup-Fejerskov Index (TFI). All samples were analyzed by atomic force microscopy.The mean values of enamel surface roughness (ESR) in nm were: Group C, 92.6; Group MI, 188.8; Group MO, 246.9; and Group S, 532.2. The mean values of absolute depth profile in nm were: C, 1,065.7; MI, 2,360.7; MO, 2,536.7; and S, 6,146.2. The differences between mean ESR and mean ADP among groups were statistically significant (p < 0.05). This structural study confirms at the nanometer level that there is a positive association between fluorosis severity, ESR, and ADP, and there is an association with the clinical findings of fluorosis measured by TFI as well.


2015 ◽  
Vol 22 (05) ◽  
pp. 1550066 ◽  
Author(s):  
YUANXIN FENG ◽  
CHUHANG ZHANG

Gold atomic aggregates are fabricated by vapor-depositing Au atoms onto a silicone oil surface and the microstructure evolution is investigated by atomic force microscopy (AFM) observation. It is found that the Au aggregates are composed of Au circular nanoparticles with diameter around 45 nm, which is independent with the nominal film thickness d. As d increases from 1 nm to 15 nm, the height of the nanoparticles increases from 15 nm to 25 nm, indicating the geometric shape of the Au nanoparticles evolves from plateau to spherical. Furthermore, the roughness analysis shows that the mean surface roughness increases linearly with d in the range of 1 nm–15 nm, which is quite different from the findings in Ag system. The anomalous microstructure evolution of Au aggregates suggests that the growth of Au aggregates may be dominated by the shadowing effect.


2008 ◽  
Vol 14 (5) ◽  
pp. 380-386 ◽  
Author(s):  
Ana Carolina Botta ◽  
Sillas Duarte ◽  
Pedro Iris Paulin Filho ◽  
Simoni Maria Gheno

AbstractRoughness increases significantly after finishing procedures. The aim of this study was to assess by the atomic force microscope (AFM) the effect of finishing instruments on the surface roughness of composite resins. A nanofiller composite resin (Filtek Supreme, 3M–F) and a microhybrid composite resin (Point 4, Kerr–P) were selected. The finishing procedures were done with a 30-blade carbide bur (C) and a 30-μm finishing diamond bur (D). Standardized specimens were produced and divided into six experimental groups (n= 4) according to (1) composite resin, (2) absence of finishing (Mylar matrix–M), and (3) finishing instrument (FM, PM, FC, FD, PC, PD). The mean surface roughness was evaluated by AFM in the contact mode. FM and PM groups were assessed statistically by the Student's T test, and FC, FD, PC, PD groups were submitted to variance analysis (ANOVA), both at 5% significance. The mean surface roughness values, in nanometers, were FM, 23.63 (b); FC, 283.88 (c); FD, 510.55 (d); PM, 12.52 (a); PC, 343.98 (c); PD, 531.64 (d). Microhybrid composite displayed less roughness than nanofiller composite in the absence of finishing procedures. The 30-blade carbide bur produced less roughness compared to the extra fine diamond bur.


2009 ◽  
Vol 615-617 ◽  
pp. 643-646 ◽  
Author(s):  
Akimasa Kinoshita ◽  
Takashi Nishi ◽  
Takasumi Ohyanagi ◽  
Tsutomu Yatsuo ◽  
Kenji Fukuda ◽  
...  

The Ti/4H-SiC Schottky barrier diodes with a field limiting ring (FLR) structure are fabricated. Two types of SBDs are prepared; one (SBD-A) is covered and another (SBD-B) isn’t covered with a carbon cap during high temperature annealing after ion implantation. The breakdown voltage at room temperature for SBD-A and SBD-B are 1400 V and 1000 V, respectively. The breakdown for both SBDs occurs due to an avalanche breakdown. The light emission images are obtained at the breakdown voltage by photo emission microscope (PEM). The light emission is observed along an FLR of the SBD-A as designed. On the other hand, the spot of light emission is observed on a FLR structure of the SBD-B. This light emission spot indicates that leakage current is concentrated because an electrical field concentration is generated at this one for the SBD-B. The root-mean-square roughness of the Al-implanted region on the FLR structure calculated from the atomic force microscopy (AFM) images for the SBD-A and the SBD-B are 0.697 nm and 5.58 nm, respectively. Therefore it is considered that large surface roughness on the FLR decreases breakdown voltage of SBD because an electrical field concentration is generated at a spot.


2014 ◽  
Vol 925 ◽  
pp. 92-95
Author(s):  
Zaliman Sauli ◽  
Vithyacharan Retnasamy ◽  
Uda Hashim ◽  
Steven Taniselass ◽  
Moganraj Palianysamy ◽  
...  

This study reports on the preliminary investigations on the effect of Reactive Ion Etch (RIE) parameters on the surface characteristics of Al bond pad. Investigation is done employing Design of Experiment (DOE) method. Quantity of Oxygen, Argon, ICP power and BIAS power were varied to get 16 sets of recipes. This provides 16 samples with different combination of RIE parameters. Surface characteristics of the samples were analyzed using Atomic Force Microscopy (AFM).Data collected were in terms of Surface Roughness (RA), Peak Vs Valley (P-V) and Surface Root-Mean-Square Roughness (RMS). Result shows that combination of these RIE parameters does not vastly affect the surface characteristics of the Al bond pad.


Author(s):  
H. Kinney ◽  
M.L. Occelli ◽  
S.A.C. Gould

For this study we have used a contact mode atomic force microscope (AFM) to study to topography of fluidized cracking catalysts (FCC), before and after contamination with 5% vanadium. We selected the AFM because of its ability to well characterize the surface roughness of materials down to the atomic level. It is believed that the cracking in the FCCs occurs mainly on the catalysts top 10-15 μm suggesting that the surface corrugation could play a key role in the FCCs microactivity properties. To test this hypothesis, we chose vanadium as a contaminate because this metal is capable of irreversibly destroying the FCC crystallinity as well as it microporous structure. In addition, we wanted to examine the extent to which steaming affects the vanadium contaminated FCC. Using the AFM, we measured the surface roughness of FCCs, before and after contamination and after steaming.We obtained our FCC (GRZ-1) from Davison. The FCC is generated so that it contains and estimated 35% rare earth exchaged zeolite Y, 50% kaolin and 15% binder.


2000 ◽  
Vol 629 ◽  
Author(s):  
Jonathan S. Schulze ◽  
Timothy P. Lodge ◽  
Christopher W. Macosko

ABSTRACTThe reaction of perdeuterated amino-terminal polystyrene (dPS-NH2) with anhydrideterminal poly(methyl methacrylate) (PMMA-anh) at a PS/PMMA interface has been observed with forward recoil spectrometry (FRES). Bilayer samples were constructed by placing thin films of PS containing ∼8.5 wt % dPS-NH2 on a PMMA-anh layer. Significant reaction was observed only after annealing the samples at 174°C for several hours, a time scale at least two orders of magnitude greater than the time required for the dPS-NH2 chains to diffuse through the bulk PS layer. The topography of the interfacial region as copolymer formed was measured using atomic force microscopy (AFM). Roughening of the PS/PMMA interface was observed to varying degrees in all annealed samples. Furthermore, the extent of this roughening was found to depend on the PS matrix molecular weight. Reaction in the samples with a high molecular weight PS matrix resulted in a root mean square roughness approximately equal to the radius of gyration Rg of the copolymer. However, approximately twice as much roughening was observed in the low molecular weight PS matrix. This study reveals how the molecular weight of one of the phases can affect the rate of reaction at a polymer/polymer interface.


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