Shaping of Dense Advanced Ceramics and Coatings by Gelation of Polysaccharides

Abstract

The application of the gelling properties of some polysaccharides in the consolidation of ceramics (gel casting) allows the forming of dense complex-shape samples through colloidal routes. A description of those polysaccharides, their gelling mechanisms (chemical and thermal), and their synergistic interaction with non gelling polysaccharides is revised, as well as their application in the shaping of 3D (bulk) and 2D (substrates, coatings, and laminates) ceramics. The materials obtained by this methodology show both homogeneous microstructures and high green mechanical strengths, which make possible the machining in the green state, with the corresponding costs reduction.

Ovalbumin as foaming agent for Ti6Al4V foams produced by gelcasting

“…This technique is suitable to produce complexshaped porous components with good mechanical properties [8]. The control of pore size and connectivity is possible through the variation of the expansion of the foams before setting [9].…”

“…To the best of our knowledge, the gelcasting technique, relying on the temperatureinduced gelling of various biopolymers, such as globular proteins [8], has only been very rarely used for the production of metallic foams.…”

A Finite Element Analysis for Improvement of Shaping Process of Complex-Shaped Large-Size Silicon Carbide Mirrors

“…The homogenous distribution of the polymer using the gel-casting technique contributes to the higher strength of the SiC materials. So far, many examples involved in the application of the gel casting in forming silicon carbide green samples can be found in the reported literature [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. Tian et al [ 24 ] successfully prepared the SiC ceramics using the gel-casting process and proposed a pretreatment and surface modification method to avoid the problem that Isobam is difficult to crosslink and gelling with non-oxide ceramics.…”

Thermoanalytical studies of the ceramic-metal composites obtained by gel-centrifugal casting

“…The concept of gel-casting, belonging to shaping methods based on colloidal processes, was first presented by researchers from Oak Ridge National Laboratory in 1990 [4,5]. This method is a well-known colloidal technique in the preparation of high-quality, complex-shape, tough green bodies by means of polymerization of organic monomers in the ceramic suspensions [6][7][8][9][10]. The method does not require the use of sophisticated equipment as in case of injection molding [4].…”