Publications associées à Sub micrometer ceramic structures fabricated by molding a polymer-derived ceramic

Liquid metal infiltration of silicon based alloys into porous carbonaceous materials Part-III: Experimental verification of conversion products and infiltration depth by infiltration of Si-Zr alloy into mixed SiC/ graphite preforms

Ludger Weber, Alberto Ortona, Manoj Kondibhau Naikade, Caroline Hain, Annapaola Parrilli

Porous carbonaceous preforms, made from graphite and silicon carbide (SiC) powders, with varying graphite powder mass fractions and particle sizes, were infiltrated at 1500 degrees C and 1700 degrees C by Si-8 at. pct Zr alloy to produce dense Si-Zr-SiC co ...

ELSEVIER SCI LTD2023

Multiscale microshaping of functionally graded polymer-derived SiCN ceramics

Lorenz Hagelüken

Polymer-derived ceramics (PDCs) exhibit excellent properties and are compatible with many shaping techniques due to the liquid character of the preceramic polymers (PCPs). Furthermore, their properties are adjustable by modifying the precursor composition ...

EPFL2022

Study and characterization of silicon metal alloys systems for the reactive infiltration process of ceramic matrix composites

Manoj Kondibhau Naikade

Silicon infiltrated silicon carbide (SiSiC) is one of the most promising and economical non-oxide ceramic matrix composites for high-temperature structural applications. In recent years infiltration by Si-alloys instead of pure Si has become popular to avo ...

EPFL2021

Additive micro-manufacturing of crack-free PDCs by two-photon polymerization of a single, low-shrinkage preceramic resin

Helena Van Swygenhoven, Jürgen Brugger, Demetri Psaltis, Christophe Moser, Nikolaos Nianias, Eirini Kakkava, Georgia Konstantinou, Lorenz Hagelüken, Jieping Wang

Additive manufacturing (AM) methods are being integrated in ceramics fabrication either as the main manufacturing tool or for auxiliary purposes. By using polymers, powders and preceramic formulated materials, AM techniques are pushing towards higher resol ...

2020

Spark Plasma Sintering of Ceramics: From Modeling to Practice

Paul Bowen, Michael Stuer, Zhe Zhao

Summarizing the work of nearly a decade of research on spark plasma sintering (SPS), a review is given on the specificities and key factors to be considered in SPS of ceramic materials, based on the authors’ own research. Alumina is used primarily as a mod ...

2020

Dynamic wetting in pressure-infiltration of ceramic particle preforms by molten metal

Gionata Schneider

This thesis investigates the interaction between mechanically induced flow of a liquid metal into a porous solid, and kinetic effects at the triple line. The approach is experimental and focuses on metal-ceramic systems for which the literature gives value ...

EPFL2019

Ni-Al2O3 nacre-like composites through hot-pressing of freeze-cast foams

A multi-step process is developed to create a nacre-like ceramic/metal composite. First, a slurry of Ni-coated alumina platelets and NiO nano-particles is directionally freeze-cast and the ice is sublimed, creating a foam with aligned lamellar walls contai ...

2019

Probing the micromechanical strength of oxide ceramic composite reinforcements

Václav Pejchal

This work shows how one can probe the micromechanical strength of ceramic reinforcements used in metal matrix composites, which greatly influences the mechanical performance of the composite material yet has seldom been quantified with precision. More spec ...

EPFL2017

Comparison of apparent activation energies for densification of alumina powders by pulsed electric current sintering (spark plasma sintering) and conventional sintering-toward applications for transparent polycrystalline alumina

Paul Bowen, Claude Paul Carry, Michael Stuer, Zhe Zhao

In the quest for high real in-line transmittances for transparent polycrystalline alumina (PCA), we need defect free processing. One of the biggest advances in producing high density defect free ceramics over recent years has been the advent of spark plasm ...

Materials Research Society2017

Strength and fracture of silicon second-phase particles in aluminium casting alloys

Martin Guillermo Mueller

The mechanical behaviour of metallic materials that have a microstructure composed of a brittle phase embedded in a ductile matrix is dictated by a complex interplay of factors such as local phase properties, cohesive properties, geometrical characteristic ...

EPFL2017

Self-Replenishing, Wear-Resistant and Anti-Sticking Surfaces Based on Liquid Impregnation of Microstructured Mesoporous α-AI₂O₃ [Alpha Alumina] Matrices

Sriharitha Rowthu

Fabrication of wear-resistant omniphobic surfaces is a persistent scientific challenge and essential for various applications such as in paint industries, fluid transport, antifouling, reduction of friction drag on ship hulls, and stain resistant textiles. ...

EPFL2016

Grain boundary complexion and transparent polycrystalline alumina from an atomistic simulation perspective

Paul Bowen, Abhishek Tewari

Transparent alumina is often processed with sintering additives such as, Y, La, and Mg, in order to limit its grain growth at high sintering temperatures. Usually, these additives segregate to the grain boundaries due to their larger cationic size than Al ...

Elsevier2016

Surface 3D Micro Free Forms: Multifunctional Microstructured Mesoporous alpha-Alumina by in Situ Slip Casting Using Excimer Laser Ablated Polycarbonate Molds

Paul Bowen, Patrik Willi Hoffmann, Sriharitha Rowthu

Ceramic surface microstructuring is a rapidly growing field with a variety of applications in tribology, wetting, biology, and so on. However, there are limitations to large-area microstructuring and fabrication of three-dimensional (3D) micro free forms. ...

Amer Chemical Soc2015

Toward Knowledge-Based Grain-Boundary Engineering of Transparent Alumina Combining Advanced TEM and Atomistic Modeling

Paul Bowen, Marco Cantoni, Michael Stuer, Cécile Hébert, Abhishek Tewari, Farhang Nabiei

Transition element dopants (e.g., Y, La) are commonly used as sintering aids in polycrystalline alumina ceramics, which segregate to the grain boundaries and control the grain-boundary mobility. However, due to the extremely thin (

Wiley-Blackwell2015

Reactive friction stir processing of AA 5052-TiO2 nanocomposite: process-microstructure-mechanical characteristics

Friction stir processing (FSP) is a solid state route with a capacity of preparing fine grained nanocomposites from metal sheets. In this work, we employed this process to finely distribute TiO2 nanoparticles throughout an Al-Mg alloy, aiming to enhance me ...

Maney Publishing2015

Effect of interfacial interactions on the electromechanical response of poly(vinylidene fluoride-trifluoroethylene)/BaTiO3 composites and its time dependence after poling

Dragan Damjanovic, Yves Leterrier, Véronique Michaud, Sara Dalle Vacche

Solvent cast and compression molded composite films based on poly(vinylidene fluoride-trifluoroethylene), containing pristine and silylated BaTiO3 particles, were poled, and their electromechanical response (d(33)), their dielectric properties, and the cry ...

Elsevier2015

Dynamic crack propagation in a heterogeneous ceramic microstructure, insights from a cohesive model

Seyedeh Mohadeseh Taheri Mousavi

Silicon nitride is a widely used industrial ceramic, specifically for dynamic loading applications because of its special mechanical and material properties. The investigation of the underlying mechanisms which lead to these properties is experimentally ch ...

EPFL2015

Segregation of anion (Cl−) impurities at transparent polycrystalline α-alumina interfaces

Paul Bowen, Marco Cantoni, Cécile Hébert, Abhishek Tewari, Farhang Nabiei

Small amounts of anion impurities (e.g. Cl), which are incorporated during the synthesis of ceramic powders, can affect the properties and microstructure of the final sintered ceramic. The effect of anion impurities is a little studied and poorly understoo ...

Elsevier Sci Ltd2014

Performance of ceramic anvils for high pressure neutron scattering

Livia Eleonora Bove Kado

Three kinds of ceramics, zirconia-toughened alumina (ZTA), alumina-toughened zirconia (ATZ) and yttria-stabilized zirconia (YSZ), were tested as anvil materials, mainly for the purpose of neutron scattering study under high pressure. ZTA with non-toroidal ...

Taylor & Francis Ltd2014

High Temperature Behavior of Nano-Structured Ceramic Composites Studied by Mechanical Spectroscopy

Mehdi Mazaheri

Silicon nitride based ceramics (SiAlONs); tetragonal polycrystalline zirconia (3Y‐TZP); alumina and their composites reinforced with different amount of multi‐ walled carbon‐nanotubes (CNTs) have been processed by Spark Plasma Sintering (SPS). High tempera ...

EPFL2013