Shaping ceramics by plastic processing

Blackburn, S.; Wilson, D.I.

doi:10.1016/j.jeurceramsoc.2007.12.013

Cited by 28 publications

(10 citation statements)

References 102 publications

(73 reference statements)

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“…It is preferable to produce the simplest carrier system due to the manufacturing, storage and economic benefits. However, as the area of study is sometimes considered more of an art than a science it is not uncommon to find, as stated by Blackburn and Wilson, that some paste or dough systems used in industry evolve into complex mixtures (4). Some of these can contain over 10 components due to practitioners 'tweaking' the formulations to overcome processing issues as and when they appear, rather than developing a comprehensive understanding.…”

Section: Introductionmentioning

confidence: 99%

Investigation into Paraffin Wax and Ethylene Vinyl Acetate Blends for Use as a Carrier Vehicle in Ceramic Injection Molding

Standring

Blackburn

Wilson

2016

Polymer-Plastics Technology and Engineering

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An experimental study into paraffin wax (PW) and ethylene vinyl acetate (EVA-28) blends has been undertaken to investigate the potential for their use as carrier vehicles for ceramic injection moulding applications. Carrier systems are critical for the fabrication of this type of moulded component; making their properties at all stages of the process of great importance. Blend formulation was performed on a modified planetary mixer, with materials testing and characterisation being conducted through thermogravimetric analysis, differential scanning calorimetry, rheometry and mechanical testing. Crystallisation was captured using a hot stage optical microscope. PW and EVA-28, in most circumstances, combine to form stable homogeneous blends, which experience relatively small changes in the melting and solidification phase transition behaviour. However, these blends exhibit notable viscosity shifts and flexural strength performance changes with increasing EVA-28 content. The melt flow behaviour of the blends at shear rates of 100 s-1 varies from 0.01 Pa.s for PW to 10 Pa.s for the composition by weight of 50 % PW and 50 % EVA-28, which literature suggests is the upper limit of viscosities for successful carrier systems. All PW/EVA-28 blends experience shear thinning behaviour with increasing shear rate, which can be modelled with reasonable accuracy using the Cross and Carreau models. Increasing the EVA-28 content in a blend causes the initiation of shear thinning at progressively lower shear rates and also forms a blend with an increasing elastic character at typical injection temperature. Yield stress is not developed for blends containing less than fifty weight percent EVA-28. The addition of EVA-28 significantly alters the mechanical properties of the blends, modifying the brittle nature of PW to develop increasing flexible and plastic properties. Although with less than twenty-five weight percent EVA-28 in a blend fracture failure still results, greater EVA-28 content represses the failure mechanisms developing increasing degrees of plastic deformation.

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Section: Introductionmentioning

confidence: 99%

Investigation into Paraffin Wax and Ethylene Vinyl Acetate Blends for Use as a Carrier Vehicle in Ceramic Injection Molding

Standring

Blackburn

Wilson

2016

Polymer-Plastics Technology and Engineering

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“…The role and effect of dispersants and polymer chains on the viscoelasticity of alumina suspensions has been previously examined as well as with charged polymers such as polysaccharides, natural gums, carbopol, etc . However, extensive characterization using nonadsorbed PVP of different molecular weights as a polymer carrier has yet to be investigated.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, high ceramic concentrations (>50 vol%) are achievable, allowing for the fabrication of green bodies with higher densities resulting in higher attainable densities in pressureless sintered samples. 23 The role and effect of dispersants and polymer chains on the viscoelasticity of alumina suspensions has been previously examined 4,5,12,13,[16][17][18][19][20][21]24,25 as well as with charged polymers such as polysaccharides, natural gums, carbopol, etc. [26][27][28][29][30][31] However, extensive characterization using nonadsorbed PVP of different molecular weights as a polymer carrier has yet to be investigated.…”

Section: Introductionmentioning

confidence: 99%

Effect of Polyvinylpyrrolidone Additions on the Rheology of Aqueous, Highly Loaded Alumina Suspensions

et al. 2013

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The control of the rheological behavior of highly loaded ceramic/polymer suspensions affords the development of near-net shape forming techniques. In this study, suspensions containing sub-micrometer diameter alumina (up to 56 vol%) were fabricated using an anionic dispersant (%4 vol%) and water-soluble polyvinylpyrrolidone (PVP). The amount and ratio of molecular weights of PVP in the suspension were varied to influence flow behavior. The final pH of the system, %9.5, was higher than the isoelectric point (IEP) of alumina implying that the alumina powder possesses a negative surface charge. In the case of alumina at this pH, PVP does not adsorb onto the surface of the powder. The flow behavior of the PVP-containing suspensions displayed yield-pseudoplastic characteristics that closely agreed with the Herschel-Bulkley fluid model. The addition of PVP significantly changed the rheology of the system, increasing the shear yield stress and altering flow behavior. Interparticle interaction approximations of the suspensions were modeled to correlate with experimental observations.

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“…This orientation effect is well known and often observed. [18][19][20] for plastic processing of ceramics, such as injection molding, slip casting, and extrusion of suspensions, containing aspherical particles. Besides processing parameters and components' dimensions the orientation of particles, more or less depends on the aspect ratio of the particle.…”

Section: Feasibility and Quality Of Replicationmentioning

confidence: 99%

Manufacturing of Net‐Shape Reaction‐Bonded Ceramic Microparts by Low‐Pressure Injection Molding

et al. 2009

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Reaction‐bonded oxide ceramics based on intermetallic compounds are able to compensate the sintering shrinkage completely due to their high increase in volume caused by oxidation. Using low‐pressure injection molding (LPIM) for shaping ceramics avoids needless materials loss and affords the manufacturing of complex formed structures. The combination of both, reaction‐bonded ceramic and LPIM‐processing, offers the manufacturing of ceramic microparts by keeping a high accuracy and replication quality.

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Shaping ceramics by plastic processing

Cited by 28 publications

References 102 publications

Investigation into Paraffin Wax and Ethylene Vinyl Acetate Blends for Use as a Carrier Vehicle in Ceramic Injection Molding

Investigation into Paraffin Wax and Ethylene Vinyl Acetate Blends for Use as a Carrier Vehicle in Ceramic Injection Molding

Effect of Polyvinylpyrrolidone Additions on the Rheology of Aqueous, Highly Loaded Alumina Suspensions

Manufacturing of Net‐Shape Reaction‐Bonded Ceramic Microparts by Low‐Pressure Injection Molding

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