Surface Roughness Of Composites Research Articles

Effects of deposition method and conditions for IGZO film and thermal annealing on composite film quality, surface roughness, microstructural defects, and electrical properties of Ti/IGZO/graphene/polyimide specimens

The depositions of a thin graphene as the inter layer of the indium gallium zinc oxide (IGZO) film and polyimide substrate and a Ti film bellow the IGZO layer to induce the IGZO crystallizations have been reported by the authors' study [1] to have a significant reduction in the electrical resistivity (R) and increases in carrier mobility (Mb) and concentration (Cc) via the annealing as compared to those created in the specimens without graphene. In the present study, Ti/IGZO/graphene/polyimide specimens were fabricated using Ti as the top layer, with the IGZO film prepared using e-beam evaporation and radio-frequency magnetron sputtering, in order to compare the ability of preserving the structure integrity of graphene after the IGZO deposition. When sputtering was used, the thicknesses of the Ti and IGZO films were controlled by the deposition power; when e-beam evaporation was used, the thicknesses were controlled by the deposition time. Rapid thermal annealing (RTA) was further applied to some specimens to investigate the combined effects of the IGZO deposition method and heat treatment on the microstructure defects, electrical and mechanical properties, and surface morphology of the specimens. The quantities of bulges and microvoid defects increase after the RTA, and become the governing factors for increasing surface roughness (Ra). The X-ray photoelectron spectroscopy spectra for O1s were deconvoluted to evaluate the peak intensity ratio, IRO2, defined for the evaluation of the oxygen vacancies in the microstructure. When sputtering was used, IRO2 increased after RTA; in contrast, when e-beam evaporation was used, IRO2 decreased after RTA. For all specimens without RTA, an increase in either the deposition power or time of IGZO has decreased IRO2. TiO2, ZnO, and Ga2O3 are the three oxides created in the specimens. The ways of increasing the TiO2 grains result in a rise of IRO2. The electrons released from the TiO2 formations are available to raise the quantity of ZnO. The peak intensity (PIZnO) of ZnO is lowered by annealing, irrespective of the IGZO deposition method. With sputtering and without RTA, increasing the IRO2 value increased the carrier mobility (Mb), but decreased the resistivity (R) and carrier concentration (Cc), irrespective of the deposition power. After the RTA, carrier concentration and resistivity are lowered, and carrier mobility is risen. With e-beam evaporation and without RTA, the vague interface between Ti and IGZO films and the void defects in IGZO make these electrical properties more complicated in behavior and dependent on IGZO deposition time. Specimen's resistivity was lowered and carrier concentration was elevated by applying the RTA. The deposition of the Ti film as top layer can result in a much bigger reduction of R and further increases in Mb and Cc for these two IGZO deposition methods as compared to those shown in Ref. [1].

Surface Roughness of Ceramic-Resin Composites After Femtosecond Laser Irradiation, Sandblasting or Acid Etching and Their Bond Strength With and Without Silanization to a Resin Cement.

The aim of this study was to investigate the effects of femtosecond laser irradiation, sandblasting, or acid etching treatments on the surface roughness of ceramic-resin composites and also shear bond strength (SBS) with and without silanization to a resin cement. Samples of Vita Enamic (VE; Vita Zahnfabrik, Bad Säckingen, Germany) and Lava Ultimate (LU; 3M ESPE, Seefeld, Germany) were classified into control (no treatment), sandblasting, hydrofluoric acid, and femtosecond laser groups (n=30). Surface roughness was determined using two-dimensional contact profilometry. Surface topography was evaluated using a three-dimensional contact profilometer and a scanning electron microscope. Then groups were divided into two subgroups with similar surface roughness values, including control (C), control + silane (C-S), sandblasting (SB), sandblasting + silane (SB-S), hydrofluoric acid (HF), hydrofluoric acid + silane (HF-S), femtosecond laser (FS), and femtosecond laser + silane (FS-S) groups (n=15). Panavia F 2.0 resin cement was applied to the sample surfaces using an SDI SBS rig (SDI Limited, Bayswater, Australia). The SBS test was performed after water storage (24 h, 37°C) and thermocycles (2000 cycles, 5°C to 55°C), and failure modes were evaluated. The highest surface roughness was observed in the FS group, and the highest SBS was observed in the FS-S group for both VE and LU ( p<0.001). Silanization improved the SBS of VE significantly ( p<0.001) in all surface treatments but did not improve that of LU except in the FS group ( p=0.004). There was a significantly moderate negative correlation in the VE/SB group ( p=0.012) and a moderate positive correlation in the VE/HF group ( p=0.049). Femtosecond laser irradiation was found to be more effective than sandblasting or acid etching in increasing the surface roughness, and it was also the most effective surface treatment with silanization on the SBS of a resin cement to the ceramic-resin composites.

Investigation of EDM Process parameters for Hybrid Metal Matrix Composites

The goal of present research work is to investigate the Electrical discharge Machining process parameters namely current, pulse on time and combined equal weight percentage of silicon carbide and graphite on material removal rate, tool wear rate and surface roughness of hybrid metal matrix composites. Experimental trails are done by Taguchi’s L27 orthogonal array. Signal to noise ratio is used to determine optimal setting of process parameters. Analysis of Variance is utilized to discover the most influential machining process parameters on output responses. This examination have shown results of ideal machining condition which can be utilized to boost material removal rate as well as to limit tool wear rate and surface roughness. Finally results are validated by confirmation Tests.

Surface topography and roughness of silicon carbide ceramic matrix composites

The silicon carbide ceramic matrix composite (Cf/SiC) plays an important role in aeronautic and space applications due to its excellent performance. Cf/SiC consists of silicon carbide and carbon fibers. The effects of the grinding parameters on the 3D parameters of surface roughness and surface topography when grinding 2.5D needled Cf/SiC materials have rarely been investigated. The primary purpose of this paper is to fill this knowledge gap. Cf/SiC material was ground in the direction of the orthogonal surface, and the surface topography, grinding parameters and grinding mechanism were analysed through a series of experiments. The results indicated that matrix cracks, fiber fractures, fiber wear and interfacial debonding were the primary removal methods of the material. The grinding parameters exert a substantial influence on the quality of the machined surface, primarily because of the undeformed chip thickness and the length of the contact arc. In the grinding process of the 2.5D Cf/SiC material, the quality of the surface roughness and its parameters gradually improved with increasing grinding speed, whereas the feed speed and grinding depth produced the opposite effect. Based on the conclusions, the surface topography and roughness parameters of 2.5D Cf/SiC material can be predicted, which thus provides useful technical support for increasing the machining quality of 2.5D Cf/SiC material and all its composites.

Effect of Surface Sealants and Polishing Time on Composite Surface Roughness and Microhardness.

The objective of this study was to evaluate the effect of surface sealants and polishing delay time on a nanohybrid resin composite roughness and microhardness. Eighty disc specimens were made with a nanohybrid resin (Esthet-X HD, Dentsply). The specimens were divided into two groups (n=40) according to polishing time: immediate, after 10 minutes; delayed, after 48 hours. Each group was subdivided into four groups (n=10), according to the surface treatment: CG, control-rubber points (Jiffy Polishers, Ultradent); PP, rubber points + surface sealant (PermaSeal, Ultradent); PF, rubber points + surface sealant (Fortify, Bisco); PB, rubber points + surface sealant (BisCover, Bisco). Surface roughness (Ra) and microhardness (50 g/15 seconds) were measured. Surface morphology was analyzed by scanning electron microscopy and atomic force microscopy. The data were analyzed statistically using one-way analysis of variance and the Games-Howell post hoc test (α=0.05). PermaSeal roughness (G2) in the delayed polishing group was significantly higher ( p=0.00) than that of the other groups. No difference was observed among the groups between immediate and delayed polishing ( p=1.00), except for PermaSeal ( p=0.00). Moreover, PermaSeal showed the lowest microhardness values ( p=0.00) for immediate polishing. Microhardness was higher at delayed polishing for all the surface treatments ( p=0.00) except Fortify ( p=0.73). Surface smoothness similar to polishing with rubber points was achieved when surface sealants were used, except for PermaSeal surface sealant, which resulted in a less smooth resin composite surface. However, surface sealant application did not significantly improve composite resin microhardness.

Surface roughness of nanofilled and nanohybrid composite resins exposed to kretek cigarette smoke

Background: Cigarette smoking is a public health issue that may influence the physical properties of dental composites. Surface roughness is one of the physical properties of restorative materials potentially influencing their success. The use of nanofilled and nanohybrid composites in dentistry has increased substantially over the past few years. Purpose: The purpose of this study was to evaluate the surface roughness of nanofilled and nanohybrid composite resins exposed to kretek cigarette smoke. Methods: Twelve cylindrical specimens of each material were prepared and divided into two groups (n=6). In the control groups, the specimens were immersed in distilled water for 24 hours at 37°C, with the water being renewed daily. For the experimental groups, the specimens were exposed to kretek cigarette smoke on a daily basis, then washed and soaked in distilled water at 37°C. After 21 days, the specimens were measured using a Surface Roughness Tester and the data was then statistically analyzed. Results: An Independent-T Test revealed that there were statistically significant differences in the surface roughness between the control and experimental groups of both nanofilled and nanohybrid composites, as well as between the nanofilled experimental group and the nanohybrid experimental group. Conclusion: Exposure to kretek cigarette smoke can increase the surface roughness of nanohybrid composites to a significantly greater extent than nanofilled composites.

Influence of beverages and surface roughness on the color change of resin composites.

The aim of the present study was to determine the degree of surface staining and roughness of resin composites (RC) after finishing and polishing with different methods and immersion in three soft drinks. A microhybrid, a nanohybrid, and a hybrid composite were selected. The specimens were prepared and divided into three groups of 36 after 24hours, and designated as either unpolished or polished using Sof-Lex discs or Enhance point. Each group was further divided into three subgroups, immersed in distilled water, coffee, or cola for 1week (N=12). Color change (∆E) was measured by a spectrophotometer after each treatment. The ∆E was calculated using the following formula: ∆E=([∆L]2+[∆a]2+[∆b]2)1/2. Surface roughness (Ra) was measured after 24hours and 1week. To observe the Ra, a scanning electron microscope was used. A moderate correlation between Ra and ∆E was determined. Only coffee caused perceptible ∆E. The effect of Ra on staining was statistically significant (P<.05), but immersion in solutions for 7days did not increase the Ra of RC. The highest Ra values were obtained from hybrid RC. The Enhance point created the greatest roughness. Coffee was associated with the greatest ∆E for all materials and polishing methods.

Influence of Polishing System on the Surface Roughness of Flowable and Regular-Viscosity Bulk Fill Composites.

This study evaluated the influence of polishing protocols on the surface roughness of flowable and regular bulk fill composites. Five bulk fill composites were tested: SureFil SDR Flow (SDR), Tetric EvoFlow Bulk fill (TEF), Filtek Bulk Fill Flowable (FIF), Tetric EvoCeram Bulk Fill (TEC), and Filtek Bulk Fill Posterior (FIP). Two polishing protocols were tested: Sof-Lex and Astropol. Astropol created a smoother surface for FIP (P < .05); however, the polishing protocol did not influence surface roughness on TEC (P > .05). SDR, TEF, and FIF exhibited rougher surfaces when polished. Sof-Lex created rougher surfaces for bulk fill composites. It was concluded that surface roughness was related to material composition rather than the polishing system.

The evaluation of surface sealants' effect on the surface roughness of Nano-hybrid composite after polishing with One-Step system (in-vitro).

BackgroundThe clinical use of composite resins has increased substantially due to increased esthetic demands by patients, improvements in formulation, and simplification of bonding procedures. Use of surface sealants is recommended to improve surface smoothness of composite restorations. The aim of this study was to evaluate the effect of surface sealants on the surface roughness of nano-hybrid composite after polishing with One-Step system.Material and MethodsUsing a silicon mold, 56 specimens of 10 mm diameter and 2 mm height were prepared from Grandio nano-hybrid composite (Voco, Cuxhaven, Germany) with A2 shade. Specimens were randomly divided in 2 groups. The surface of specimens were polished with VOCO One-step system. One group of specimens assigned as control group and received no more surface treatment. Surface sealant PermaSeal (Ultradent, USA) was applied on the surface of specimens of the other group as experimental group. Specimens were stored in Ringer’s solution at 37°C for 24 hours. The specimens were subjected to artificial accelerated aging with thermocycling method (3000 cycles, between 5 and 55°C) and then 100000 cycles of tooth brushing. A Profilometer was used to measuring the surface roughness of specimens before and after aging procedures.ResultsThe surface roughness changes of control group were significant before and after aging (P<0.05). The mean final surface roughness of control group was unacceptable clinically while it was acceptable in experimental group.ConclusionsThe use of surface sealants on nano-hybrid composite causes noticeable reduces in surface roughness of composite. Key words:Surface-penetrating sealant, surface roughness, nano-hybrid, composites, one-step polishing.

Comparison of two finishing and polishing systems on the surface roughness of resin composites using a non-contact profilometer

Comparison of two finishing and polishing systems on the surface roughness of resin composites using a non-contact profilometer

Modeling and experimental investigation of process parameters in WEDM for surface roughness using regression model

The present study focused on the multiple regression modeling and predicting the surface roughness of the Aluminum hybrid composite during the WEDM process. The hybrid MMC was manufactured by process named as stir casting utilizing particulates of Silicon carbide and graphite each in Al6061 combination. The analyses were outlined with Taguchi L27 design matrix. Mathematical relationships between the surface roughness and WEDM cutting parameters (Pulse on time, Pulse off time, current, gap voltage, wire speed and wire tension) have been investigated. The results show that the multiple regression analysis is a successful method for developing a mathematical model to predict the surface roughness. The optimum value of process parameters for the predicted optimum value of surface roughness (1.285) is pulse on time 106 units (Level 1), pulse off time 60 units (Level 3), peak current 90 units (Level 2), gap set voltage 50 units (Level 3), wire speed3 units (Level 1) and wire tension 12 units (Level 3).The optimum results are adopted in validation study and the results based on WEDM process responses can be effectively improved.

Mathematical modeling and optimization of EDM Process Parameters for Aluminium Hybrid composites

The objective of this paper is to establish mathematical model and study combined effect of electrical discharge machining process parameters on material removal rate, tool wear rate and surface roughness of Aluminium hybrid composites. The hybrid composite is consisting of Aluminium alloy (AC2B) as metal matrix material reinforced with combined equal weight percentage of silicon carbide (5-15 wt%) and graphite particles (5-15 wt%). The specimen of hybrid composites are manufactured by stir casting method and machined by electrical discharge machining process. Furthermore, it is subjected to the mathematical analysis and analysis of variance as well.

Effect of different finishing/polishing procedures on surface roughness of Ormocer-based and different resin composites

The aim of this study was to evaluate and compare the surface roughness of six esthetic restorative materials (Gradia Direct Anterior, GC Corporation, Tokyo, Japan; Filtek Supreme XTE, 3M ESPE, St. Paul, MN, USA; Ceram.X Universal, Dentsply DeTrey, Konstanz, Germany; Essentia enamel, GC Corporation, Tokyo, Japan; Admira Fusion, Voco, Cuxhaven, Germany; and Estelite, Tokuyama Dental corporation, Taitou-ku, Tokyo, Japan) achieved using three different finishing and polishing techniques. In this in vitro study Forty specimens of each material (6 mm in diameter, 2 mm high) were created and divided into four groups, one per each finishing and polishing procedure and a control group, only cured and not polished. All specimen preparation and finishing and polishing procedures were performed by the same investigator, to reduce variability, following strictly the manufacturer's instructions. Specimens were analyzed using a profilometer to measure the mean surface roughness (Ra, μm), and microscopy images were taken during the measurements through the microscope of the profilometer. Two-way ANOVA test was applied to determine significant differences with respect to material, finishing/polishing technique, and interaction between both variables. Post hoc comparison was done using Tukey's honestly significant difference test. Significance for statistical tests was predetermined at P < 0.05. Finishing and polishing procedure using tungsten carbide burs provided the best values in terms of surface roughness. All materials of this study treated with this method have provided superimposable values, and no material can be considered more performing than the others. Similar values were also found in the control group. This study demonstrated that the finishing technique with carbide burs produced an excellent surface smoothness, even if the best surface smoothness is achieved curing the restorative material under a polyester matrix.

Experimental study and empirical analyses of abrasive waterjet machining for hybrid carbon/glass fiber-reinforced composites for improved surface quality

Poor surface quality is one of the critical defects after trimming of fiber-reinforced plastic (FRP) composites through both conventional and non-conventional machining processes. With the recent introduction of hybrid composites from different fiber reinforcements, this makes the trimming or cutting of them challenging. Therefore, an experimental study was attempted to elucidate the effect and relationship between the machining parameters in the abrasive waterjet cutting, namely abrasive flow rate, hydraulic pressure, and stand-off distance, and traverse rate on the surface roughness of the machined composites. An optimum setting of machining parameters and mathematical modeling equation were obtained by applying the response surface methodology for improving the surface quality. It is apparent that the abrasive flow rate and stand-off distance contributed the most in affecting the surface roughness of the hybrid FRP composites. The mathematical relationship, which is in the form of quadratic function, has been validated with confirmation test in order to optimize the surface roughness.

Surface roughness, gloss and color change of different composites after exposure to ultimate challenges

Aim: The study aimed to investigate the effect of the association of chemical and mechanical degradation on the surface roughness, gloss and color of nano and microfilled composites. Method: Disc-shaped specimens (n=10) were prepared for three nanocomposites (Filtek Z350XT, IPS Empress Direct, Charisma Diamond) and three microfilled composites (Estelite Σ Quick, Durafill VS, Renamel). After polishing, baseline surface roughness, gloss and color measurements were obtained. Specimens were submitted subsequently to the following challenges: chemical for 1 week (Hydrochloric acid, Coca-Cola and Red Wine) and mechanical (Toothbrushing). Surface roughness and gloss data were analyzed by Kruskal-Wallis followed by Dunn’s test. Color difference (ΔE) was analyzed by one-way ANOVA and Tukey test. Results: The initial data were compared with those after challenges using the Wilcoxon test (p&lt;0.05). All composites showed a significant increase (p&lt;0.05) of surface roughness, after overstress. Filtek Z350 XT and Renamel had the lowest final surface roughness values and roughness increase (p&lt;0.05). The comparative analysis revealed that Estelite Σ Quick and Renamel did not significantly change the gloss after challenges (p=0.185). Filtek Z350 XT and IPS Empress Direct had higher color variations, after the challenges than the other resins (p&lt;0.05). Conclusion: Chemical and mechanical challenges influence on characteristics of all composites, except for gloss on Estelite Σ Quick and Renamel composites.

Evaluation of Color Stability and Surface Roughness of Bulk-Fill Resin Composites and Nanocomposites

Evaluation of Color Stability and Surface Roughness of Bulk-Fill Resin Composites and Nanocomposites

The effect of chewing simulation on surface roughness of resin composite when opposed by zirconia ceramic and lithium disilicate ceramic

ObjectiveTo assess the change in surface roughness of nanohybrid resin composite (Tetric EvoCeram) after antagonist wear against monolithic zirconia and lithium disilicate ceramics through a simulated chewing test using a three-dimensional (3D) profilometer. MethodsA total of 40 Tetric EvoCeram™ resin composite specimens against either a Lava™ Plus zirconia antagonist (n=20) or IPS e.max Press lithium disilicate antagonist (n=20) were prepared for the study. The surface roughness profiles of each resin composite before and after an in-vitro simulated chewing test were analysed using a 3D profilometer and Talymap software. After the simulated chewing, the surface profiles of representative Tetric EvoCeram specimens from each group were analysed using scanning electron microscopy. Independent t-test and paired t-test were used for statistical analysis. ResultsFor both lithium disilicate and zirconia groups, all surface roughness parameters (Ra, Rt, Sa, Sq,) of Tetric EvoCeram were significantly higher post-chewing compared to pre-chewing (p<0.05); the post-chewing surface roughness parameters of Tetric EvoCeram for the lithium disilicate group were significantly higher (p<0.05) than in the zirconia group. SignificanceThis chewing simulation test showed that Tetric EvoCeram composites exhibited a rougher surface when opposing lithium disilicate ceramic compared to opposing zirconia ceramic.

Surface changes of various bulk-fill resin-based composites after exposure to different food-simulating liquid and beverages.

To evaluate surface roughness, hardness, and morphology changes of various bulk-fill resin composites eroded by different food-simulating liquids and beverages. One hundred and thirteen specimens were fabricated in polytetrafluoroethylene cylindrical mold (10 mm in diameter and 4 mm in thickness). Before immersion, baseline data of roughness, Vicker's microhardness were recorded and surface characteristics were examined using scanning electron microscopy (SEM). Each product of specimens (SDR, Dentsply; SonicFill, Kerr; Tetric N-Ceram Bulk Fill, Ivoclar Vivadent AG; and Filtek Bulk Fill, 3M ESPE) were divided into 5 groups for spicy and sour soup, spicy soup (Tom Yum), pineapple juice, passionfruit juice, and deionized water (served as a control). Specimens were then alternately immersed in storage agents for 5 seconds and artificial saliva for 5 seconds over 10 cycles. Specimens were stored in artificial saliva for 22 hours. This process was repeated for 28 days. After immersion, surface hardness and roughness of specimens were evaluated at 7, 14, 21, and 28 days and data were analyzed by two-way repeated ANOVA and Tukey's HSD (α = 0.05). Surface morphology of specimens was also examined on day 28. The SDR group had the most statistically significant decrement in hardness (25.65±1.74 kg/mm2 in mean difference) and increment in roughness (0.26±0.10 μm in mean difference; P < .05). Passionfruit juice caused the most surface changes in bulk-fill resin composites. SEM photomicrographs showed surface changes of all resin composites in varying degrees. Acidic food-simulating liquids and beverages significantly increased the surface roughness and decreased surface microhardness of bulk-fill resin composites after evaluation at the end of the 28-day immersion period. For restoration of the affected teeth in patients who consume acidic food and beverages, roughness and erosion of resin composites should be considered. All of bulk-fill resin-based composites except SDR may be suitable for restorations in these patients.

Investigations on mechanical and machinability behavior of aluminum/flyash cenosphere/Gr hybrid composites processed through compocasting

Abstract This work focuses on characterization of a novel hybrid Aluminum Metal Matrix Composite (AMMC) developed through two-step compocasting method by reinforcing constant amount of flyash cenosphere (10%) and varying quantity of graphite (2%, 4% and 6%). Morphological analysis result shows the presence of dendritic arms and homogeneous distribution of the cenosphere and graphite in Al7075 matrix. The hardness and tensile strength upturn with addition of cenosphere and vice versa for the addition of graphite. The reinforcement particles have enhanced the tensile strength of Aluminum matrix from 178 N/mm2 to 213 N/mm2 as of the composite is concerned. Addition of cenosphere improves the wear resistance considerably and wear rate decreases further with graphite addition due to its self-lubricating nature. Machinability (turning) characteristics of the developed hybrid composite were studied in detail besides optimizing the machining parameters employing Artificial Neural Network (ANN) technique. Based on the ANOVA results it was found that cutting speed and % of graphite addition have the major contribution in minimizing the surface roughness of developed composite.

Color Stability and Surface Roughness of Composites after Artificial Accelerated Aging

The color stability and surface uniformity are very important properties for dental aesthetics. Objective: To evaluate the color stability and surface roughness of different composites after artificial accelerated aging (AAA). Methods: Samples were made using the silorane-based Filtek P90 (3M-ESPE), nanohybrid Tetric N-Ceram (Ivoclar Vivadent), and GC Kalore (GC Company). Ceramic D. Sign (Ivoclar Vivadent) and Ketac N100 (3M-ESPE) resin-modified glass ionomer cement (RMGIC) served as controls. The values for color stability and surface roughness were recorded before and after AAA for non-C-UV (300 hours). Color stability was assessed as the difference between the coordinates obtained from the L*a*b* system. The surface roughness was analyzed with a rugosimeter. The surface value of each sample was taken as the average of these measurements. The one-way ANOVA and Tukey’s post-test with α=5% was used. Results: The greatest change in color stability occurred for the RMGIC (ΔE=18.7) and the least for ceramics (ΔE=2.1). No significant difference was noted among the composites (p>0.05). The surface roughness before and after AAA differed significantly only for the RMGIC (p<0.05). Conclusion: The two latest generation resins (Filtek P90 and GC Kalore) showed good results in terms of color stability and surface roughness for use in aesthetic restorations.