Universität Stuttgart

Now showing 1 - 5 of 5

Open Access
Modelling and experimental validation of the flame temperature profile in atmospheric plasma coating processes on the substrate
(2024) Martínez-García, Jose; Martínez-García, Venancio; Killinger, Andreas
This work presents a characterisation model for the temperature distribution at different substrate depths during the atmospheric plasma spray (APS) coating process. The torch heat flow in this model is simulated as forced convection defined by a surface, a temperature profile, and a convection coefficient. The simulation model considers three plasma temperature profiles of the Al2O3 coating on a 5 mm thickness flat aluminium substrate. The simple and low-cost experimental procedure, based on a thermocouple, measures the plasma plume temperature distribution of the APS coating system, and their results are used to obtain the parameter values of each of the three proposed plasma temperature profiles. The experimental method for in situ non-contact temperature measurements inside the substrate is based on an infrared pyrometry technique and validates the simulation results. The Gaussian temperature profile shows excellent accuracy with the measured temperatures. The Gaussian approach could be a powerful tool for predicting residual stress through a coupled one-way thermal-mechanical analysis of the APS process.
Open Access
Additive manufacturing of β-tricalcium phosphate components via Fused Deposition of Ceramics (FDC)
(2020) Eßlinger, Steffen; Grebhardt, Axel; Jäger, Jonas; Kern, Frank; Killinger, Andreas; Bonten, Christian; Gadow, Rainer
Das Paper beschreibt die Compoundierung bioaktiver Keramik (Beta-Tricalciumphosphat) in einer organischen Matrix, die anschließende Extrusion zu Filamenten, die für den FDM-3D-Druck geeignet sind, sowie die Formgebund zu Scaffolds mittels additiver Fertigung. Weiterhin werden fertigungsprozessbegleitende Untersuchungen zur Entbinderung und Sinterung durchgeführt.
Open Access
Funktionsschichten für industrielle Anwendungen : Energieeinsparung durch neue Glaskeramikkochsysteme, Leichtmetallwerkstoffe im Fahrzeugbau, Schichtverbundstrukturen für Implantate
(2003) Killinger, Andreas
Das komplexe Anforderungsprofil moderner ingenieur- und werkstofftechnischerAufgabenstellungen bedingt in zunehmendem Maße den Einsatz von Werkstoffkombinationen in Form von Verbundmaterialien und Verbundbauweisen. Ein Einzelwerkstoff kann in seiner Funktion den gestellten Anforderungen im Allgemeinen nicht mehr gerecht werden.
Open Access
Resonant atmospheric plasma-sprayed ceramic layers effectively absorb microwaves at 170 GHz
(2022) Hentrich, Andreas; Garcia, Venancio Martinez; Killinger, Andreas; Plaum, Burkhard; Lechte, Carsten; Tovar, Günter E. M.
AbstractMicrowave absorbing layer materials (MALMs) are extremely important for many components in fusion reactors to absorb microwave radiation in a controlled manner and with predictable power density. Therefore, a detailed knowledge of absorption properties of absorber coating materials used is necessary. Plasma-sprayed mixed oxide coatings are most commonly used in those applications where moderate power density is expected. In this paper, a plane wave absorption model is presented using refractive index and absorption coefficient as internal parameters and incidence angle, polarization, and layer thickness as external parameters. The model has been calculated assuming radiation of 170 GHz, as envisaged for the ITER research facility. Three atmospheric plasma-sprayed coating materials were considered in this work: titanium dioxide (TiO2), chromium oxide (Cr2O3), and a mixed aluminum-titanium oxide Al2O3-TiO2 (40/60). Theoretical results are compared with free wave measurements with two antennas. Different coating thicknesses have been prepared and measured in different polarization and incidence angles. Results are discussed regarding polarization, incidence angle, layer thickness, absorption coefficient, and refractive index.
Open Access
Suspension-sprayed calcium phosphate coatings with antibacterial properties
(2024) Lanzino, Maria Carolina; Le, Long-Quan R. V.; Höppel, Anika; Killinger, Andreas; Rheinheimer, Wolfgang; Dembski, Sofia; Al-Ahmad, Ali; Mayr, Hermann O.; Seidenstuecker, Michael
Prosthesis loosening due to lack of osteointegration between an implant and surrounding bone tissue is one of the most common causes of implant failure. Further, bacterial contamination and biofilm formation onto implants represent a serious complication after surgery. The enhancement of osteointegration can be achieved by using bioconductive materials that promote biological responses in the body, stimulating bone growth and thus bonding to tissue. Through the incorporation of antibacterial substances in bioconductive, biodegradable calcium phosphate (CaP) coatings, faster osteointegration and bactericidal properties can be achieved. In this study, Cu-doped CaP supraparticles are spray-dried and suspension-sprayed CaP ceramic coatings with antibacterial properties are prepared using high-velocity suspension flame spraying (HVSFS). The objective was to increase the coatings’ porosity and investigate which Cu-doped supraparticles have the strongest antibacterial properties when introduced into the coating layers. Biocompatibility was tested on human Osteosarcoma cells MG63. A porosity of at least 13% was achieved and the supraparticles could be implemented, enhancing it up to 16%. The results showed that the addition of Cu-doped supraparticles did not significantly reduce the number of viable cells compared to the Cu-free sample, demonstrating good biocompatibility. The antimicrobial activity was assessed against the bacterial strains Escherichia coli and Staphylococcus aureus , with Safe Airborne Antibacterial testing showing a significant reduction in both Gram-positive and Gram-negative strains on the Cu-doped coatings.

Universität Stuttgart

Browse

Filters

Settings

Sort By

Results per page

Search Results