Michael Scheffler
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Formation of Protective Coatings on TZM Molybdenum Alloy by Complex Aluminosiliconizing and Application of a Preceramic Layer Open
The use of molybdenum-based alloys as materials for components operating under high temperatures and significant mechanical loads is widely recognized due to their excellent mechanical properties. However, their low high-temperature resist…
View article: Corrosion Resistance of Coatings Based on Chromium and Aluminum of Titanium Alloy Ti-6Al-4V
Corrosion Resistance of Coatings Based on Chromium and Aluminum of Titanium Alloy Ti-6Al-4V Open
Improvement of wear, corrosion, and heat-resistant properties of coatings to expand the operational capabilities of metals and alloys is an urgent problem for modern enterprises. Diffusion titanium, chromium, and aluminum-based coatings ar…
Strength Increase of Alumina Foams by a Sodium Aluminosilicate Glass Coating with Subsequent Na<sup>+</sup> ↔ K<sup>+</sup> Ion Exchange (Gorilla Glass Coating) Open
Reticulated alumina ceramic foams manufactured by the Schwartzwalder technique are coated with a sodium aluminosilicate glass using an aqueous precursor containing alumina particles and sodium silicate. After a heat treatment, a well‐adher…
View article: Physicochemical Conditions of Boron–Siliconizing of Molybdenum-Based Alloys in Chlorine and Fluorine Medium
Physicochemical Conditions of Boron–Siliconizing of Molybdenum-Based Alloys in Chlorine and Fluorine Medium Open
The physicochemical conditions of the siliconizing and boron–siliconizing processes of molybdenum-based alloys in a closed reaction space in an environment of chlorine and fluorine at reduced pressure were studied. Theoretical calculations…
Increased Microporosity in Ceramic and Metal Foams: A Novel Processing Combination Open
Copper, aluminum, and alumina foams are prepared by a combination of reticulated foaming and freezing processing. This results in all of these foams in an additional strut porosity consisting of lamellar pores and material lamellae; the la…
Processing of Ceramics from Polysil(sesquioxane)‐Type Precursors: Coatings, Tapes, Tailored Surfaces, and Porosity Control Open
Poly(silsesquioxane)‐based polymer‐derived ceramics (PDCs), may be manufactured by a great variety of processes and process combinations leading to ceramic parts seven with high functionality. Advantage of the use of poly(silsesquioxane)s …
Effect of Powder Processing and Sintering Conditions on the Microstructural, Thermal, and Mechanical Properties of Reticulated Zinc Oxide Ceramic Foams Open
Ceramic foams are made of zinc oxide using different amounts of Sb 2 O 3 and Bi 2 O 3 as sintering aids. The effect of a ball milling processing of the starting powders and the sintering temperature on the microstructure and the properties…
Reticulated open‐cellular aluminum nitride ceramic foams: Effect of sintering aids on microstructural, thermal, and mechanical properties Open
Open‐celled aluminum nitride ceramic foams were prepared by the polymer sponge replication technique involving aqueous dispersions of passivated AlN. The amount of the Y 2 O 3 and Dy 2 O 3 as sintering aid was varied, and the effects on th…
Effect of the Cell Count on Geometrical, Mechanical, and Thermal Properties of Hierarchical‐Porous Reticulated Copper Foams from a Combination of Sponge Replication and Freeze‐Drying Techniques Open
Copper foams are manufactured from polyurethane template foams with a cell size of 10 and 30 ppi using two techniques: Sponge replication and a combination of sponge replication with additional freezing steps to obtain lamellar strut pores…
Manufacturing of Open-Cell Aluminium Foams: Comparing the Sponge Replication Technique and Its Combination with the Freezing Method Open
The manufacturing of aluminium foams with a total porosity of 87% using the sponge replication method and a combination of the sponge replication and freezing technique is presented. Foams with different cell counts were prepared from poly…
Modeling the oxidation of a polymer-derived ceramic with chemo-mechanical coupling and large deformations Open
To get a better insight into the coating behavior of a polymer-derived ceramic material, we model and simulate the diffusion, oxidation and reaction-induced volume expansion of a specimen without outer mechanical loads. In this macroscale …
Reticulated ceramic foams from alumina‐chromia solid solutions: A feasibility study Open
Open cellular ceramic foams were manufactured from plain and chromia‐doped alumina, with a chromium concentration ranging between 1.25 mol% and 5.0 mol%. The (AlCr) 2 O 3 starting powders were prepared by precipitation of a chromia precurs…
Refractory Metal Coated Alumina Foams as Support Material for Stem Cell and Fibroblasts Cultivation Open
Ceramics are widely used as implant materials; however, they are brittle and may emit particles when used in these applications. To overcome this disadvantage, alumina foams, which represent a 3D cellular structure comparable to that of hu…
Hierarchical‐Porous Copper Foams by a Combination of Sponge Replication and Freezing Techniques Open
Open‐porous copper foams with additional strut porosity are manufactured by two different manufacturing routes. The first is based on the Schwarzwalder sponge replication technique. The second method is a combination of Schwartzwalder spon…
Open-Cellular Alumina Foams with Hierarchical Strut Porosity by Ice Templating: A Thickening Agent Study Open
Alumina replica foams were manufactured by the Schwartzwalder sponge replication technique and were provided with an additional strut porosity by a freeze-drying/ice-templating step prior to thermal processing. A variety of thickeners in c…
Oxidation‐Resistant Environmental Barrier Coatings for Mo‐Based Alloys: A Review Open
Molybdenum‐based materials offer high melting temperatures and promising mechanical properties; therefore, they are potential candidates for high‐temperature components, such as turbine blades. However, at temperatures above 700 °C, molybd…
Polymer Derived Ceramics from Si, B, SiB6, and Mo5SiB2 Filler-Loaded Perhydropolysilazane Precursors as Protective and Functional Coatings for Refractory Metal Alloys Open
Oxidation barrier coatings on the base of a perhydropolysilazane precursor with different amounts of Si, B, SiB6 and Mo5SiB2 (T2) fillers for the oxidation protection of Mo-Si-B alloys were developed. The influence of different filler comp…
Manufacturing of Open-Cell Metal Foams by the Sponge Replication Technique Open
Different manufacturing techniques for open-cell metal foams, such as investment casting and space holder casting, are compared with the sponge replication technique that is originally used for the preparation of ceramic foams. Processing …
Preceramic polymer-derived ceramic foams with lamellar strut porosity Open
Open porous replica foams with additional lamellar strut pores were prepared by preceramic polymer processing combined with a freeze-drying process. Polymer foam templates were coated with an aqueous polymethylsilesquioxane system followed…
Novel Al/Al<sub>2</sub>O<sub>3</sub>composite foams by direct oxidation conversion Open
In this paper we combined an investment casting technique and a direct oxidation conversion (DOC) method to fabricate novel Al/Al 2 O 3 composite foams. We treated open cellular Al foams with dense struts in oxidizing atmosphere and obtain…
Ceramic oxidation protection coatings for refractory alloys from filler-loaded preceramic polymers: The role of particle size and volume fraction of particulate fillers Open
Oxidation protection coatings on the base of perhydridopolysilazane (PHPS) polymer and Si/B filler materials were developed to prevent Mo-basis alloys against oxidation at 800 °C. Within this work the influence of the particle size and the…
Cellular Nickel-Yttria/Zirconia (Ni–YSZ) Cermet Foams: Manufacturing, Microstructure and Properties Open
Open-celled ceramic composite foams were prepared from NiO and yttria-stabilized zirconia (YSZ) powders by the polymer sponge replication (Schwartzwalder) technique using the respective aqueous dispersions. Mechanically stable NiO–YSZ foam…
Acoustic metamaterial capsule for reduction of stage machinery noise Open
Noise mitigation of stage machinery can be quite demanding and requires innovative solutions. In this work, an acoustic metamaterial capsule is proposed to reduce the noise emission of several stage machinery drive trains, while still allo…
Open‐Cell Aluminum Foams by the Sponge Replication Technique: A Starting Powder Particle Study Open
Open‐cell aluminum foams are manufactured by a sponge replication technique, and the effect of aluminum particles with different shapes and particle sizes on foam properties is studied. It is found that aluminum powder with spheroidal part…
Open-Cell Aluminum Foams by the Sponge Replication Technique Open
Open-cell aluminum foams were manufactured by a sponge replication technique having a total porosity of ~90%. The influence of the thermal processing conditions such as atmosphere and temperature on the cellular structure, phase compositio…
Reticulated Alumina Replica Foams with Additional Sub‐Micrometer Strut Porosity Open
Ceramic alumina foams are suitable catalyst supports with high temperature stability used, for example, in catalytic cracking processes or combined heat and power units. Herein, such replica foams are generated from macroporous α‐Al 2 O 3 …
Tailored Oxidation Barrier Coatings for Mo-Hf-B and Mo-Zr-B Alloys Open
The cyclic oxidation response of Mo-14Hf-23B and Mo-14.8Zr-26B (compositions in at. %) was investigated in air at 800 °C, which is a critical temperature for Mo-based alloys because of the pesting phenomenon. Rapid oxidation was observed f…