scholarly journals Investigation of Post-Processing of Additively Manufactured Nitinol Smart Springs with Plasma-Electrolytic Polishing

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4093
Author(s):  
Vincent N. Stepputat ◽  
Henning Zeidler ◽  
Daniel Safranchik ◽  
Evgeny Strokin ◽  
Falko Böttger-Hiller
Keyword(s):  
Mechanical Load ◽  
Load Test ◽  
Polished Surface ◽  
Post Processing ◽  
Scanning Calorimetry ◽  
Processing Times ◽  
Dsc Measurements ◽  
Electrolytic Polishing ◽  
Compression Springs ◽  
Plasma Electrolytic

Additive manufacturing of Nitinol is a promising field, as it can circumvent the challenges associated with its conventional production processes and unlock unique advantages. However, the accompanying surface features such as powder adhesions, spatters, ballings, or oxide discolorations are undesirable in engineering applications and therefore must be removed. Plasma electrolytic polishing (PeP) might prove to be a suitable finishing process for this purpose, but the effects of post-processing on the mechanical and functional material properties of additively manufactured Nitinol are still largely unresearched. This study seeks to address this issue. The changes on and in the part caused by PeP with processing times between 2 and 20 min are investigated using Nitinol compression springs manufactured by Laser Beam Melting. As a benchmark for the scanning electron microscope images, the differential scanning calorimetry (DSC) measurements, and the mechanical load test cycles, conventionally fabricated Nitinol springs of identical geometry with a medical grade polished surface are used. After 5 min of PeP, a glossy surface free of powder adhesion is achieved, which is increasingly levelled by further polishing. The shape memory properties of the material are retained without a shift in the transformation temperatures being detectable. The decreasing spring rate is primarily attributable to a reduction in the effective wire diameter. Consequently, PeP has proven to be an applicable and effective post-processing method for additively manufactured Nitinol.

scholarly journals Polypropylene/Lignin/POSS Nanocomposites: Thermal and Wettability Properties, Application in Water Remediation

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3950
Author(s):  
Abeer Alassod ◽  
Syed Rashedul Islam ◽  
Mina Shahriari Khalaji ◽  
Rogers Tusiime ◽  
Wanzhen Huang ◽  
...  
Keyword(s):  
Organic Liquid ◽  
Contact Angles ◽  
Water Remediation ◽  
Scanning Calorimetry ◽  
Water Contact ◽  
Thermally Induced ◽  
Dsc Measurements ◽  
Infrared Measurement ◽  
Oligomeric Silsesquioxane ◽  
Tga And Dsc

Compositing is an interesting strategy that has always been employed to introduce or enhance desired functionalities in material systems. In this paper, sponges containing polypropylene, lignin, and octavinyl-polyhedral oligomeric silsesquioxane (OV-POSS) were successfully prepared via an easy and elegant strategy called thermally induced phase separation (TIPS). To fully explore the behaviour of different components of prepared sponges, properties were characterized by a thermogravimetric analyser (TGA), differential scanning calorimetry (DSC), Fourier transform infrared measurement (FTIR), and scanning electron microscopy (SEM). Furthermore, wettability properties toward an organic liquid and oil were investigated. The FTIR analysis confirmed the chemical modification of the components. TGA and DSC measurements revealed thermal stability was much better with an increase in OV-POSS content. OV-POSS modified sponges exhibited ultra-hydrophobicity and high oleophilicity with water contact angles of more than 125°. The SEM revealed that POSS molecules acted as a support for reduced surface roughness. Moreover, OV-POSS-based blend sponges showed higher sorption capacities compared with other blend sponges without OV-POSS. The new blend sponges demonstrated a potential for use as sorbent engineering materials in water remediation.

scholarly journals Metallization of Thermoplastic Polymers and Composites 3D Printed by Fused Filament Fabrication

Technologies ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 49
Author(s):  
Alessia Romani ◽  
Andrea Mantelli ◽  
Paolo Tralli ◽  
Stefano Turri ◽  
Marinella Levi ◽  
...  
Keyword(s):  
Physical Vapor Deposition ◽  
Test Sample ◽  
Tensile Tests ◽  
Layer By Layer ◽  
Post Processing ◽  
Thermoplastic Polymers ◽  
Fused Filament Fabrication ◽  
Scanning Calorimetry ◽  
3D Printed ◽  
Manufacturing Technologies

Fused filament fabrication allows the direct manufacturing of customized and complex products although the layer-by-layer appearance of this process strongly affects the surface quality of the final parts. In recent years, an increasing number of post-processing treatments has been developed for the most used materials. Contrarily to other additive manufacturing technologies, metallization is not a common surface treatment for this process despite the increasing range of high-performing 3D printable materials. The objective of this work is to explore the use of physical vapor deposition sputtering for the chromium metallization of thermoplastic polymers and composites obtained by fused filament fabrication. The thermal and mechanical properties of five materials were firstly evaluated by means of differential scanning calorimetry and tensile tests. Meanwhile, a specific finishing torture test sample was designed and 3D printed to perform the metallization process and evaluate the finishing on different geometrical features. Furthermore, the roughness of the samples was measured before and after the metallization, and a cost analysis was performed to assess the cost-efficiency. To sum up, the metallization of five samples made with different materials was successfully achieved. Although some 3D printing defects worsened after the post-processing treatment, good homogeneity on the finest details was reached. These promising results may encourage further experimentations as well as the development of new applications, i.e., for the automotive and furniture fields.

scholarly journals Poly(HDDA)-Based Polymers for Microfabrication and Mechanobiology

MRS Advances ◽  
2017 ◽  
Vol 2 (24) ◽  
pp. 1315-1321 ◽  
Author(s):  
Daniela Espinosa-Hoyos ◽  
Huifeng Du ◽  
Nicholas X. Fang ◽  
Krystyn J. Van Vliet
Keyword(s):  
Polyethylene Glycol ◽  
Additive Manufacturing ◽  
Progenitor Cell ◽  
Materials Processing ◽  
Biological Applications ◽  
Post Processing ◽  
Mechanical Stiffness ◽  
Processing Times ◽  
Low Stiffness ◽  
Cell Material Interactions

ABSTRACTMaterials processing and additive manufacturing afford exciting opportunities in biomedical research, including the study of cell-material interactions. However, some of the most efficient materials for microfabrication are not wholly suitable for biological applications, require extensive post-processing or exhibit high mechanical stiffness that limits the range of applications. Conversely, materials exhibiting high cytocompatibility and low stiffness require long processing times with typically decreased spatial resolution of features. Here, we investigated the use of hexanediol diacrylate (HDDA), a classic and efficient polymer for stereolithography, for oligodendrocyte progenitor cell (OPC) culture. We developed composite HDDA-polyethylene glycol acrylate hydrogels that exhibited high biocompatibility, mechanical stiffness in the range of muscle tissue, and high printing efficiency at ∼5 μm resolution.

Investigations on the polymorphism and pseudopolymorphism of clobetasone butyrate

2011 ◽  
Vol 76 (5) ◽  
pp. 553-566
Author(s):  
Christian Näther ◽  
Inke Jeß
Keyword(s):  
Room Temperature ◽  
Polymorphic Form ◽  
Stable Form ◽  
Scanning Calorimetry ◽  
Amorphous Form ◽  
Space Group ◽  
Dsc Measurements ◽  
Independent Molecules ◽  
Solvent Molecules ◽  
Similar Conformation

Clobetasone butyrate was investigated for polymorphism and pseudopolymorphism. Solvent mediated conversion experiments reveal that the commercially available form I represent the thermodynamically most stable form at room temperature and DSC measurements shows that it should also be the most stable form until melting. Form I crystallizes in space groupP212121with three crystallographically independent molecules of similar conformation. From methanol an additional pseudo polymorphic form was discovered. In the crystal structure (space groupP212121) the solvent molecules are connected to the clobetasone butyrate molecules by O–H···O hydrogen bonding. Investigations of the solvate using thermogravimetry, differential thermoanalysis as well as differential scanning calorimetry proves, that on solvent removal an amorphous form is obtained that crystallizes into form I on further heating.

Effects of Aging on the Microstructure and Phase Transformation Behavior of Cu-Al-Mn Shape Memory Alloy

2021 ◽  
Vol 882 ◽  
pp. 21-27
Author(s):  
Seyed Veghar Seyedmohammadi ◽  
Amin Radi ◽  
Guney Guven Yapici
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Aging Treatment ◽  
Scanning Calorimetry ◽  
Dsc Measurements ◽  
Peak Aged Condition ◽  
Peak Aged ◽  
Rolled Condition ◽  
The One ◽  
Effects Of Aging

In the present work, the effects of artificial aging treatment on the transformation temperatures and hardness of Cu-Al-Mn shape memory alloy have been investigated. The aging processes have been performed on the one-time re-melted and 90% rolled samples. Differential scanning calorimetry reveals that reverse transformation is present for the re-melted sample which is aged at 400°C. However, in 90% rolled condition, this transformation takes place at 200°C and 300°C. Hardness examination shows that the aged specimens possess higher values in hardness in comparison to un-aged samples at all studied temperatures. Although, the peak-aged condition was demonstrated at 300°C for the re-melted sample, the rolled sample displayed increased hardness levels up to 500°C. Based on the DSC measurements and microstructural observations, it can be asserted that the thermo-mechanical processing including rolling plus aging at 300°C provides favorable transformation characteristics for shape memory behavior.

scholarly journals A Facile Synthesis and Characterization of Highly Crystalline Submicro-Sized BiFeO3

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3035
Author(s):  
Dovydas Karoblis ◽  
Diana Griesiute ◽  
Kestutis Mazeika ◽  
Dalis Baltrunas ◽  
Dmitry V. Karpinsky ◽  
...  
Keyword(s):  
Bismuth Ferrite ◽  
Cost Effective ◽  
Xrd Analysis ◽  
Synthetic Approach ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Dsc Measurements ◽  
Optimal Annealing Temperature ◽  
Synthesized Materials

In this study, a highly crystalline bismuth ferrite (BFO) powder was synthesized using a novel, very simple, and cost-effective synthetic approach. It was demonstrated that the optimal annealing temperature for the preparation of highly-pure BFO is 650 °C. At lower or higher temperatures, the formation of neighboring crystal phases was observed. The thermal behavior of BFO precursor gel was investigated by thermogravimetric and differential scanning calorimetry (TG-DSC) measurements. X-ray diffraction (XRD) analysis and Mössbauer spectroscopy were employed for the investigation of structural properties. Scanning electron microscopy (SEM) was used to evaluate morphological features of the synthesized materials. The obtained powders were also characterized by magnetization measurements, which showed antiferromagnetic behavior of BFO powders.

scholarly journals Luminescence of SiO2-BaF2:Tb3+, Eu3+ Nano-Glass-Ceramics Made from Sol–Gel Method at Low Temperature

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 259
Author(s):  
Natalia Pawlik ◽  
Barbara Szpikowska-Sroka ◽  
Tomasz Goryczka ◽  
Ewa Pietrasik ◽  
Wojciech A. Pisarski
Keyword(s):  
Sol Gel ◽  
Three Dimensional ◽  
Glass Ceramics ◽  
Emission Spectra ◽  
Scanning Calorimetry ◽  
Light Emitting ◽  
Co Doping ◽  
Dsc Measurements ◽  
Decay Times

The synthesis and characterization of multicolor light-emitting nanomaterials based on rare earths (RE3+) are of great importance due to their possible use in optoelectronic devices, such as LEDs or displays. In the present work, oxyfluoride glass-ceramics containing BaF2 nanocrystals co-doped with Tb3+, Eu3+ ions were fabricated from amorphous xerogels at 350 °C. The analysis of the thermal behavior of fabricated xerogels was performed using TG/DSC measurements (thermogravimetry (TG), differential scanning calorimetry (DSC)). The crystallization of BaF2 phase at the nanoscale was confirmed by X-ray diffraction (XRD) measurements and transmission electron microscopy (TEM), and the changes in silicate sol–gel host were determined by attenuated total reflectance infrared (ATR-IR) spectroscopy. The luminescent characterization of prepared sol–gel materials was carried out by excitation and emission spectra along with decay analysis from the 5D4 level of Tb3+. As a result, the visible light according to the electronic transitions of Tb3+ (5D4 → 7FJ (J = 6–3)) and Eu3+ (5D0 → 7FJ (J = 0–4)) was recorded. It was also observed that co-doping with Eu3+ caused the shortening in decay times of the 5D4 state from 1.11 ms to 0.88 ms (for xerogels) and from 6.56 ms to 4.06 ms (for glass-ceramics). Thus, based on lifetime values, the Tb3+/Eu3+ energy transfer (ET) efficiencies were estimated to be almost 21% for xerogels and 38% for nano-glass-ceramics. Therefore, such materials could be successfully predisposed for laser technologies, spectral converters, and three-dimensional displays.

scholarly journals Cathodic boriding and anodic polishing of medium-carbon steel by plasma electrolysis

2021 ◽  
Vol 2144 (1) ◽  
pp. 012027
Author(s):  
S S Korableva ◽  
I R Palenov ◽  
I M Naumov ◽  
A A Smirnov ◽  
I A Kusmanova ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Carbon Steel ◽  
Sulfate Solution ◽  
Medium Carbon Steel ◽  
Operating Voltage ◽  
Medium Carbon ◽  
Plasma Electrolysis ◽  
Electrolytic Polishing ◽  
Cathodic Plasma ◽  
Plasma Electrolytic

Abstract The possibility of cathodic plasma electrolytic boriding of medium-carbon steel in an aqueous solution of ammonium chloride and boric acid followed by anodic plasma electrolytic polishing in an ammonium sulfate solution on the same equipment with a change in the operating voltage is shown. The morphology and roughness of the surface, microhardness of the modified layer have been investigated. Wear resistance was studied under dry friction conditions. It has been established that cathodic boriding at 850 °C for 5–30 min leads to the hardening of the surface layer up to 1050 HV with an increase in roughness by 1.5–2.5 times and wear resistance by 3.5 times. Subsequent anodic plasma electrolytic polishing of the boriding surface leads to a decrease in roughness with an increase in wear resistance by 2.3 times.

scholarly journals Characterization of the Interface Between the Bulk Glass Forming Alloy Zr41Ti14Cu12Ni10Be23 with Pure Metals and Ceramics

2000 ◽  
Vol 15 (7) ◽  
pp. 1617-1621 ◽  
Author(s):  
Jan Schroers ◽  
Konrad Samwer ◽  
Frigyes Szuecs ◽  
William L. Johnson
Keyword(s):  
Sessile Drop ◽  
Bulk Glass ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Glass Forming ◽  
Processing Times ◽  
Thermal Stability Of

The reaction of the bulk glass forming alloy Zr41Ti14Cu12Ni10Be23 (Vit 1) with W, Ta, Mo, AlN, Al2O3, Si, graphite, and amorphous carbon was investigated. Vit 1 samples were melted and subsequently solidified after different processing times on discs of the different materials. Sessile drop examinations of the macroscopic wetting of Vit 1 on the discs as a function of temperature were carried out in situ with a digital optical camera. The reactions at the interfaces between the Vit 1 sample and the different disc materials were investigated with an electron microprobe. The structure and thermal stability of the processed Vit 1 samples were examined by x-ray diffraction and differential scanning calorimetry. The results are discussed in terms of possible applications for composite materials.

Hybrid Metal 3D Printing for Selective Polished Surface

2021 ◽  
Vol 1027 ◽  
pp. 136-140
Author(s):  
Sze Yi Mak ◽  
Kwong Leong Tam ◽  
Ching Hang Bob Yung ◽  
Wing Fung Edmond Yau
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Surface Finishing ◽  
Polished Surface ◽  
Post Processing ◽  
One Stop ◽  
Metal 3D Printing ◽  
Critical Challenge ◽  
Metal Additive

Metal additive manufacturing has found broad applications in diverse disciplines. Post processing to homogenize and improve surface finishing remains a critical challenge to additive manufacturing. We propose a novel one-stop solution of adopting hybrid metal 3D printing to streamlining the additive manufacturing workflow as well as to improve surface roughness quality of selective interior surface of the printed parts. This work has great potential in medical and aerospace industries where complicated and high-precision additive manufacturing is anticipated.

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