Detecting defects that reduce breakdown voltage using machine learning and optical profilometry.

Semiconductor wafer manufacturing relies on the precise control of various performance metrics to ensure the quality and reliability of integrated circuits. In particular, GaN has properties that are advantageous for high voltage and high frequency power devices; however, defects in the substrate growth and manufacturing are preventing vertical devices from performing optimally. This paper explores the application of machine learning techniques utilizing data obtained from optical profilometry as input variables to predict the probability of a wafer meeting performance metrics, specifically the breakdown voltage (Vbk). By incorporating machine learning techniques, it is possible to reliably predict performance metrics that cause devices to fail at low voltage. For diodes that fail at a higher (but still below theoretical) breakdown voltage, alternative inspection methods or a combination of several experimental techniques may be necessary.

Surface, microstructural and mechanical characterization of contemporary implant abutment screws.

OBJECTIVES: The aim of the present work was to evaluate six commercially available abutment screws by characterising roughness parameters, microstructure and mechanical properties. METHODS: Six abutment screws from each implant system, were used. The surface roughness parameters (Sa, Sq, Ssk, Sku, Spk, Sk and Svk) were identified by an optical interferometric profiler. Microstructural observations and crystallographic analysis were performed using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectroscopy (EDX) device for elemental analysis and an X-ray diffractometer (XRD), respectively. The Martens Hardness (HM), Indentation Modulus (EIT), elastic index (ηIT) and Vickers hardness (HV) of all specimens were determined by instrumented indentation testing (IIT). The results were analyzed by one-way ANOVA and Tukey multiple-comparison tests (a=0.05). RESULTS: EDX and XRD showed the abutment screws to be mixed α- and ß-phase titanium alloys. Microstructural analysis revealed a fine homogeneous microstructure without porosity, consisting of fine dispersoid rods of ß-phase embedded in a continuous α-phase matrix. Statistically significant differences were found among the mechanical properies and surface roughness parameters apart from Sq, Spk and Svk. CONCLUSIONS: The tested abutment screws showed significant differences in the probed properties, and, thus, differences in their clinical behaviour are anticipated.

Utilizing ablation volume for calibration in LA-ICP-MS mapping to address variations in ablation rates within and between matrices.

Quantification in 2D LA-ICP-MS mapping generally requires matrix-matched standards to minimize issues related to elemental fractionation. In addition, internal standardization is commonly applied to correct for instrumental drift and fluctuation, whereas also differences in ablated mass can be rectified for samples that cannot be sectioned and subjected to total ablation. However, it is crucial that the internal standard element is homogeneously distributed in the sample and that the laser light absorptivity is uniform over the surface. As in practice these requirements are often not met, this work will focus on correction of ablation rate differences within/between samples and standards by normalizing the element maps using the associated ablation volume per pixel as measured by optical profilometry. Due to the volume correction approach the element concentrations are no longer defined as mass per mass concentrations (in µg g-1) but by mass per volume concentrations (in µg cm-3), which can be interconverted in case matrix densities are known. The findings show that ablation volume-aided calibration yields more accurate element concentrations in 2D LA-ICP-MS maps for a decorative glass with highly varying elemental concentrations (murrina). This research presents a warning that if there are variations in ablation rates between samples and standards within and across matrices, even when their sensitivities are the same, generic LA-ICP-MS calibration protocols may not accurately depict the actual element concentrations.

Quantification of surface grinding during the sample preparation of cementitious materials by optical profilometry.

Sample preparation is of utmost importance for any microscopy and microstructural analysis. Correct preparation will allow accurate interpretation of microstructural features. A well-polished section is essential when scanning electron microscopy (SEM) is used in backscattering electron (BSE) mode and characteristic X-rays are to be quantified using an energy-dispersive spectroscopy (EDS) detector. However, obtaining a well-polished section, especially for cementitious materials containing aggregates, is considered to be challenging and requires experience. A sample preparation procedure consists of cutting, grinding and polishing. Undercutting of soft and brittle paste between harder aggregates can be overcome by vacuum epoxy impregnation offering mechanical support in the matrix. Furthermore, most of the attention during the sample preparation is given to the polishing of the sample. There is a wide range of suggestions on polishing steps, ranging from grain sizes, time and applied force; however, the final assessment of a polish surface is often subjective and qualitative. Therefore, a quantitative, reproducible guidance on the grinding steps, effect of experimental parameters and the influence of different grinding steps on the surface quality are required. In this paper, the influence of grinding was quantitatively evaluated by a digital microscope equipped with optical profilometry tools, through a step-wise procedure, including sample orientation, grinding time and the difference between cement paste and concrete. Throughout the grinding procedure, the surface profiles were determined after each grinding step. This showed the step-wise change in surface roughness and quality during the grinding procedure. Finally, the surface qualities were evaluated using optical and electron microscopy, which show the importance of the grinding/prepolishing steps during sample preparation.

Event fusion photometric stereo network.

Photometric stereo methods typically rely on RGB cameras and are usually performed in a dark room to avoid ambient illumination. Ambient illumination poses a great challenge in photometric stereo due to the restricted dynamic range of the RGB cameras. To address this limitation, we present a novel method, namely Event Fusion Photometric Stereo Network (EFPS-Net), which estimates the surface normals of an object in an ambient light environment by utilizing a deep fusion of RGB and event cameras. The high dynamic range of event cameras provides a broader perspective of light representations that RGB cameras cannot provide. Specifically, we propose an event interpolation method to obtain ample light information, which enables precise estimation of the surface normals of an object. By using RGB-event fused observation maps, our EFPS-Net outperforms previous state-of-the-art methods that depend only on RGB frames, resulting in a 7.94% reduction in mean average error. In addition, we curate a novel photometric stereo dataset by capturing objects with RGB and event cameras under numerous ambient light environments.

Understanding how bacterial collectives organize on surfaces by tracking surfactant flow.

Swarming is a collective bacterial behavior in which a dense population of bacterial cells moves over a porous surface, resulting in the expansion of the population. This collective behavior can guide bacteria away from potential stressors such as antibiotics and bacterial viruses. However, the mechanisms responsible for the organization of swarms are not understood. Here, we briefly review models that are based on bacterial sensing and fluid mechanics that are proposed to guide swarming in the pathogenic bacterium Pseudomonas aeruginosa. To provide further insight into the role of fluid mechanics in P. aeruginosa swarms, we track the movement of tendrils and the flow of surfactant using a novel technique that we have developed, Imaging of Reflected Illuminated Structures (IRIS). Our measurements show that tendrils and surfactants form distinct layers that grow in lockstep with each other. The results raise new questions about existing swarming models and the possibility that the flow of surfactants impacts tendril development. These findings emphasize that swarm organization involves an interplay between biological processes and fluid mechanics.

A Method for Spatially Registered Microprofilometry Combining Intensity-Height Datasets from Interferometric Sensors.

A recognized problem in profilometry applied to artworks is the spatial referencing of the surface topography at micrometer scale due to the lack of references in the height data with respect to the "visually readable" surface. We demonstrate a novel workflow for spatially referenced microprofilometry based on conoscopic holography sensors for scanning in situ heterogeneous artworks. The method combines the raw intensity signal collected by the single-point sensor and the (interferometric) height dataset, which are mutually registered. This dual dataset provides a surface topography registered to the artwork features up to the precision that is given by the acquisition scanning system (mainly, scan step and laser spot). The advantages are: (1) the raw signal map provides additional information about materials texture, e.g., color changes or artist marks, for spatial registration and data fusion tasks; (2) and microtexture information can be reliably processed for precision diagnostic tasks, e.g., surface metrology in specific sub-domains and multi-temporal monitoring. Proof of concept is given with exemplary applications: book heritage, 3D artifacts, surface treatments. The potential of the method is clear for both quantitative surface metrology and qualitative inspection of the morphology, and it is expected to open future applications for microprofilometry in heritage science.

Influence of different ultra-soft toothbrushes on erosive tooth wear.

OBJECTIVE: To investigate the influence of different ultra-soft toothbrushes on the progression of erosive tooth wear (ETW). METHODS: Bovine enamel and dentin specimens (n = 10) were submitted to a 5-day erosive-abrasive cycling model (0.3% citric acid for 5 min, artificial saliva for 60 min, 4x/day). Toothbrushing was carried out 2x/day for 15 s, with the different toothbrushes tested (A- Edel White: flexible handle, tapered bristles; B- Oral-B Gengiva Detox: regular handle, criss-cross tapered bristles; C- Colgate Gengiva Therapy: flexible handle, tapered bristles, high tuft density; d- Oral-B Expert Gengiva Sensi: regular handle, round end bristles, high tuft density; E- Oral-B Indicator Plus: soft brush, round end bristles (control). Surface loss (SL, in µm) was assessed by optical profilometry. The toothbrush characteristics were evaluated by a surgical microscope. Data were statistically analyzed (α=0.05). RESULTS: For enamel, toothbrush C showed the highest SL (means±SD: 9.86 ± 1.28) and it did not differ significantly from A (8.60 ± 0.50), both with flexible handles. The lowest SL was observed for the toothbrush Control E (6.76 ± 0.63), which differed significantly from A and C, but not from the other toothbrushes. For dentin, the highest SL was found for toothbrush D (6.97 ± 1.05) and it did not differ significantly from E (6.23 ± 0.71). The lowest SL was observed for B (4.61 ± 0.71) and C (4.85 + 0.83), without significant differences from A (5.01 ± 1.24). CONCLUSIONS: The ultra-soft toothbrushes had different impacts on the progression of ETW on the dental substrates. On enamel, higher ETW values were observed for the flexible handle toothbrushes, while for dentin, round-end bristles (ultra-soft and soft) caused more ETW. CLINICAL SIGNIFICANCE: Knowledge about the effect of different ultra-soft toothbrushes on ETW can help clinicians to recommend the most suitable types for their patients, bearing in mind that toothbrushes can impact enamel and dentin differently.

Bottom-Up Generated Height Gauges for Silicon-Based Nanometrology.

Steady progress in integrated circuit design has forced basic metrology to adopt silicon lattice parameter as a secondary realization of the SI meter that lacks convenient physical gauges for precise surface measurements at a nanoscale. To employ this fundamental shift in nanoscience and nanotechnology, we propose a set of self-organized silicon surface morphologies as a gauge for height measurements within the whole nanoscale (0.3-100 nm) range. Using 2 nm sharp atomic force microscopy (AFM) probes, we have measured the roughness of wide (up to 230 µm in diameter) singular terraces and the height of monatomic steps on the step-bunched and amphitheater-like Si(111) surfaces. For both types of self-organized surface morphology, the root-mean-square terrace roughness exceeds 70 pm but has a little effect on step height measurements having 10 pm accuracy for AFM technique in air. We implement a step-free 230-µm-wide singular terrace as a reference mirror in an optical interferometer to reduce the systematic error of height measurements from >5 nm to about 0.12 nm, which allows visualizing 136-pm-high monatomic steps on the Si(001) surface. Then, using a "pit-patterned" extremely wide terrace with dense but counted monatomic steps in a pit wall, we have optically measured mean Si(111) interplanar spacing (313.8 ± 0.4 pm) that agrees well with the most precise metrological data (313.56 pm). This opens up avenues for the creation of silicon-based height gauges using bottom-up approaches and advances optical interferometry among techniques for metrology-grade nanoscale height measurements.

In vivo aging-induced surface roughness alterations of Invisalign® and 3D-printed aligners.

OBJECTIVE: To assess the surface roughness of in-house 3D-printed orthodontic aligners compared with Invisalign® appliances, both retrieved as well as in the 'as-received' control status. DESIGN: An in vitro study following intra-oral material aging. SETTING AND PARTICIPANTS: Twelve clinically used Invisalign® appliances and the same number of 3D-printed aligners, without involvement of attachments, were obtained from a respective number of patients. A similar number of 'as-received' aligners, of each material, were used as control (CON) groups. METHOD: Four groups of materials were examined: A = Invisalign® CON; B = Invisalign® used; C = 3D-printed CON; and D = 3D-printed used. Optical profilometry was employed to examine the following surface roughness parameters: amplitude parameters Sa, Sq and Sz and functional parameters Sc and Sv. Descriptive statistics and quantile regression modeling were conducted, and the level of statistical significance was set at α = 0.05. RESULTS: Intra-oral exposure of 3D-printed aligners was significantly associated with increase in all tested parameters (P < 0.001 at all occasions). Significant differences were detected in the retrieved 3D-printed aligners compared with Invisalign® retrieved, with the exception of Sz. The respective effect sizes (median differences) were as follows: Sa: 169 nm, 95% confidence interval [CI] = 89-248, P < 0.001; Sq: 315 nm, 95% CI = 152-477, P < 0.001; Sc: 233 nm3/nm2, 95% CI = 131-335, P < 0.001; and Sv: 43 nm3/nm2, 95% CI = 17-68, P = 0.002. CONCLUSION: Within the limitations of this study, we concluded that surface roughness differences existed between 3D-printed aligners and Invisalign® in the retrieved status, as well as between the control and retrieved 3D-printed groups.

The impact of thickness heterogeneity on soft tissue biomechanics: a novel measurement technique and a demonstration on heart valve tissue.

The mechanical properties of soft tissues are driven by their complex, heterogeneous composition and structure. Interestingly, studies of soft tissue biomechanics often ignore spatial heterogeneity. In our work, we are therefore interested in exploring the impact of tissue heterogeneity on the mechanical properties of soft tissues. Therein, we specifically focus on soft tissue heterogeneity arising from spatially varying thickness. To this end, our first goal is to develop a non-destructive measurement technique that has a high spatial resolution, provides continuous thickness maps, and is fast. Our secondary goal is to demonstrate that including spatial variation in thickness is important to the accuracy of biomechanical analyses. To this end, we use mitral valve leaflet tissue as our model system. To attain our first goal, we identify a soft tissue-specific contrast protocol that enables thickness measurements using a Keyence profilometer. We also show that this protocol does not affect our tissues' mechanical properties. To attain our second goal, we conduct virtual biaxial, bending, and buckling tests on our model tissue both ignoring and considering spatial variation in thickness. Thereby, we show that the assumption of average, homogeneous thickness distributions significantly alters the results of biomechanical analyses when compared to including true, spatially varying thickness distributions. In conclusion, our work provides a novel measurement technique that can capture continuous thickness maps non-invasively, at high resolution, and in a short time. Our work also demonstrates the importance of including heterogeneous thickness in biomechanical analyses of soft tissues.

Estimating quantitative physiological and morphological tissue parameters of murine tumor models using hyperspectral imaging and optical profilometry.

Understanding tumors and their microenvironment are essential for successful and accurate disease diagnosis. Tissue physiology and morphology are altered in tumors compared to healthy tissues, and there is a need to monitor tumors and their surrounding tissues, including blood vessels, non-invasively. This preliminary study utilizes a multimodal optical imaging system combining hyperspectral imaging (HSI) and three-dimensional (3D) optical profilometry (OP) to capture hyperspectral images and surface shapes of subcutaneously grown murine tumor models. Hyperspectral images are corrected with 3D OP data and analyzed using the inverse-adding doubling (IAD) method to extract tissue properties such as melanin volume fraction and oxygenation. Blood vessels are segmented using the B-COSFIRE algorithm from oxygenation maps. From 3D OP data, tumor volumes are calculated and compared to manual measurements using a vernier caliper. Results show that tumors can be distinguished from healthy tissue based on most extracted tissue parameters ( p < 0.05 ). Furthermore, blood oxygenation is 50% higher within the blood vessels than in the surrounding tissue, and tumor volumes calculated using 3D OP agree within 26% with manual measurements using a vernier caliper. Results suggest that combining HSI and OP could provide relevant quantitative information about tumors and improve the disease diagnosis.

Structural changes of erythrocyte membrane revealed by 3D confocal optical profilometer.

We examined hematological changes influenced by the experimental hypervitaminosis A. The 3D confocal optical profilometer was applied for assessment of the erythrocytes' membrane structural changes influenced by an overdose of vitamin A. The blood smears were evaluated in terms of alterations of geometrical and optical parameters of erythrocytes for two groups of animals: oil base and retinol palmitate (n = 9 animals for each group). The results demonstrate that an overdose of retinol palmitate causes changes in the torus curvature and pallor of discocytes, their surface area and volume. The observed structural malformations of the shape of red blood cells become visible at the earlier preclinical stage of changes in animal state and behavior. With this in mind, the results of the study open a new area of research in the certain dysfunction diagnosis of red blood cells and have a great potential in the further development of new curative protocols.

Evaluation of the Tooth Surface after Irradiation with Diode Laser Applied for Removal of Dental Microorganisms from Teeth of Patients with Gingivitis, Using X-ray Photoelectron (XPS) and Optical Profilometry (OP).

Gingivitis is accompanied by microorganisms, including pathogens, which must be eliminated to speed up the treatment of inflammation. Laser irradiation may be one of the safe methods for reducing tissue contamination on the tooth surface. The aim of the study was the assessment of the tooth surface in patients with gingivitis after the use of a diode laser to eliminate microorganisms living there. In the first stage of the research, microorganisms were isolated (Candida albicans, C. guilliermondii, Escherichia coli, Haemophilus parainfluenzae, Klebsiella oxytoca, Neisseria subflava, Rothia dentocariosa, Rothia mucilaginosa, Streptococcus pneumoniae) from three patients with gingivitis, their identification confirmed using the MALDI-TOF MS technique (matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry). Then, the irradiation process with a diode laser was optimized to a wavelength of 810 nm ± 10 nm in five variants to reduce microorganisms on the tooth. The tooth surface was analyzed by X-ray photoelectron spectroscopy (XPS) and optical profilometry (OP) before and after irradiation. 103 to 106 CFU were detected on a 0.4 cm2 tooth area. Nine types of bacteria and two types of fungi dominated among the microorganisms. The laser at the most effective biocidal dose of 25 W/15.000 Hz/10 µs, average = 3.84 W, with three uses after 15 s, increased the reduction of fungi from 57.97% to 93.80%, and bacteria from 30.67% to 100%. This dose also caused a decrease in the degree of oxidation and in the effect of smoothing on the treated surfaces.

A 58S bioactive glass for dentin hypersensitivity and erosive tooth wear: An in vitro study.

OBJECTIVES: To assess the effect of an experimental 58S bioactive glass on dentin permeability (dP) and erosive tooth wear (dentin surface loss - dSL). METHODS: 58S bioactive glass was synthetized using a sol-gel methodology, following by lyophilization and calcination, then mixed with phosphoric acid to obtain a paste (BGP). Forty-eight dentin disks (1 mm-thick) were used for dP, and 48 dentin slabs (3 mm × 3 mm) for dSL, which were assessed at three time intervals: post-EDTA (5 min in 17% EDTA solution); post-treatment (C: distilled water; BGP: experimental bioactive glass paste; NP: Nupro prophylaxis paste; CXT: Clinpro XT varnish); and post-erosive/abrasive cycling. Data were statistically analyzed (α=0.05). RESULTS: For dP and dSL, Groups did not differ significantly post-EDTA (p>0.05). Post-treatment, all groups showed lower dP than C (p<0.05), without differing significantly among them. For the dSL analysis, Groups C, BGP and NP did not differ significantly, showing lower values than CXT (p<0.05). Post-cycling, C continued to show the highest dP (p<0.05). Specimens from Group CXT had the lowest dP and did not differ from NP (p=0.86) which did not differ from BGP (p=0.193). For C and BGP, dP value was higher post-cycling than post-treatment (p<0.05). For NP and CXT, these experimental times did not differ (p>0.05). Post-cycling, dSL for C, BGP and NP did not differ significantly; values were higher than those for CXT (p<0.05). CONCLUSIONS: BGP reduced dP after application, with a reduced effect after cycling. Nonetheless, it was not able to protect dentin against erosive tooth wear. CLINICAL SIGNIFICANCE: Minimizing dentin hypersensitivity is a challenge in the field of dentistry. The development of alternative products with potential to obliterate dentinal tubules and provide resistance to chemical/mechanical stimuli is, thus, highly desirable. We have proposed a material able to reduce dentin permeability, which has emerged as a promising alternative for this purpose.

Surface Metrology Based on Scanning Conoscopic Holography for In Situ and In-Process Monitoring of Microtexture in Paintings.

In the field of engineering, surface metrology is a valuable tool codified by international standards that enables the quantitative study of small-scale surface features. However, it is not recognized as a resource in the field of cultural heritage. Motivated by this fact, in this work, we demonstrate the use and the usefulness of surface metrology based on scanning conoscopic holography for monitoring treatments on the Venetian masterpiece by Tintoretto St. Martial in Glory with the Saints Peter and Paul. We carried out in situ and in-process monitoring of the painting microtexture during an experimental, innovative laser-chemical treatment, and we performed a statistical analysis based on ISO areal field parameters. A wide and in-band roughness analysis through the complementary use of amplitude, spatial, and hybrid parameters confirmed the noninvasive nature of the whole treatment on the painting surface topography, giving us the chance to review and critically discuss the use of these parameters in a real case in heritage science.

Microstructured Magnetoactive Elastomers for Switchable Wettability.

We demonstrate the control of wettability of non-structured and microstructured magnetoactive elastomers (MAEs) by magnetic field. The synthesized composite materials have a concentration of carbonyl iron particles of 75 wt.% (≈27 vol.%) and three different stiffnesses of the elastomer matrix. A new method of fabrication of MAE coatings on plastic substrates is presented, which allows one to enhance the response of the apparent contact angle to the magnetic field by exposing the particle-enriched side of MAEs to water. A magnetic field is not applied during crosslinking. The highest variation of the contact angle from (113 ± 1)° in zero field up to (156 ± 2)° at about 400 mT is achieved in the MAE sample with the softest matrix. Several lamellar and pillared MAE structures are fabricated by laser micromachining. The lateral dimension of surface structures is about 50 µm and the depth varies between 3 µm and 60 µm. A systematic investigation of the effects of parameters of laser processing (laser power and the number of passages of the laser beam) on the wetting behavior of these structures in the absence and presence of a magnetic field is performed. In particular, strong anisotropy of the wetting behavior of lamellar structures is observed. The results are qualitatively discussed in the framework of the Wenzel and Cassie-Baxter models. Finally, directions of further research on magnetically controlled wettability of microstructured MAE surfaces are outlined. The obtained results may be useful for the development of magnetically controlled smart surfaces for droplet-based microfluidics.

Precise Two-Dimensional Tilt Measurement Sensor with Double-Cylindrical Mirror Structure and Modified Mean-Shift Algorithm for a Confocal Microscopy System.

To improve the accuracy of three-dimensional (3D) surface contour measurements of freeform optics, a two-dimensional (2D) tilt measurement sensor for confocal microscopy (CM) systems is proposed based on a double-cylindrical mirror structure. First, the proposed system is accurately modeled. Second, we introduce a modified mean-shift-based peak-extraction algorithm with a novel kernel function (MSN) because the reflectivity of the measured object and fluctuation of the light source affect the measurement accuracy. Third, a partition fitting (PF) strategy is proposed to reduce the fitting error and improve the measurement accuracy. Simulations and experiments reveal that the robustness, speed, and angular prediction accuracy of the system effectively improved as a function of MSN and PF. The developed sensor can measure the 2D tilt, where each tilt is a composition of two separate dimensions, and the mean prediction errors in the 2D plane from -10°-+10° are 0.0134° (0.067% full scale (F.S)) and 0.0142° (0.071% F.S). The sensor enables the optical probe of a traditional CM to obtain accurate and simultaneous estimates of the 2D inclination angle and spatial position coordinates of the measured surface. The proposed sensor has potential in 3D topographic reconstruction and dynamic sampling rate optimization for 3D contour detection.

The good, the bad and the ugly polishing: Effect of abrasive size on standardless EDS analysis of Portland cement clinker's calcium silicates.

Standardless Energy dispersive spectroscopy (EDS) on polished samples of Portland cement clinker is routinely performed both for unhydrated phases as well as in cement pastes. Typically, the calcium to silica ratio is investigated. EDS analyses are highly dependent on the polishing quality of the sample. It is thus worth studying the Ca/Si ratios of cement phases in a clinker since they can be used as a reference. Indeed, alite (Ca3SiO5 or C3S in cement chemistry notation) and belite (Ca2SiO4 or C2S) should have an atomic Ca/Si ratio of 3 and 2, respectively. EDS carried out under the scanning electron microscope (SEM) is routinely used on polished samples to assess the composition of such phases. In the present study, Ca/Si ratios are investigated on a commercial clinker polished at various steps (6, 3, 1 and 0.25 µm diamond pastes, 0.05 µm alumina). All along the polishing process, ratios are coherent with theoretical ones and with the reference ones obtained by electron probe microanalysis (EMPA) in the present study.

Corrosion characterization of the 6061 Al-Mg-Si alloy in synthetic acid rain using neutron tomography.

Neutron tomography has gained increasing importance as an imaging technique for materials characterization. In general, neutron beams are able to show microstructure features of hydrogenous materials, even enfolded with thick metal layers. In the present paper, neutron tomography and observation of cross section images were successfully applied to investigate the corrosion features of the 6061 Al-Mg-Si alloy. The results showed good agreement between neutron 3D tomography and the cross section images obtained in the high attenuation areas of the samples, whereas significant differences in depth of corrosion penetration were obtained between the results from Neutron Tomography and 3D optical profilometry.