Modeling the effect of gas transport on the formation of defects during thermolysis of powder moldings

Song, J H; Edirisinghe, M J; Evans, J R; Twizell, E H

doi:10.1557/JMR.1996.0101

Title: Modeling the effect of gas transport on the formation of defects during thermolysis of powder moldings

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Abstract

The removal of binder from ceramic or metal moldings by thermolysis involves the transport of degradation products through the parent organic phase and the vacated porous body. A numerical model has been developed to combine an equation which takes into account different gas-flow regimes with an equation for the transport of organic molecules in molten polymers. Computer modeling reveals the critical heating rate above which defects occur due to boiling of the polymer-monomer solution at the center of the molding. The situation in which a porous outer layer of the molding develops, offering resistance to flow of the evolved monomer gas, is then treated. This gives rise to a moving boundary with a variable concentration of diffusant which is dependent on the surface flux, gas transport coefficient and thickness of the porous layer. The contributions of diffusion and viscous flow to gas transport are considered. {copyright} {ital 1996 Materials Research Society.}

Authors:

Song, J H; Edirisinghe, M J; Evans, J R ^[1]; Twizell, E H ^[2]

Department of Materials Technology, Brunel University, Uxbridge, Middlesex, UB8 3PH (United Kingdom)
Department of Mathematics and Statistics, Brunel University, Uxbridge, Middlesex, UB8 3PH (United Kingdom)

Publication Date:: Mon Apr 01 00:00:00 EST 1996

OSTI Identifier:: 280122

Resource Type:: Journal Article

Journal Name:: Journal of Materials Research

Additional Journal Information:: Journal Volume: 11; Journal Issue: 4; Other Information: PBD: Apr 1996

Country of Publication:: United States

Language:: English

Subject:: 36 MATERIALS SCIENCE; CERAMICS; FABRICATION; POLYMERS; POWDER METALLURGY; GAS FLOW; HEAT TRANSFER; VISCOUS FLOW; DIFFUSION; PARTICLE SIZE; MOVING-BOUNDARY CONDITIONS; COMPUTERIZED SIMULATION; DEFECTS; MOLDING

Citation Formats


                    Song, J H, Edirisinghe, M J, Evans, J R, and Twizell, E H. Modeling the effect of gas transport on the formation of defects during thermolysis of powder moldings.  United States: N. p., 1996. 
        Web.  doi:10.1557/JMR.1996.0101.

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                    Song, J H, Edirisinghe, M J, Evans, J R, & Twizell, E H. Modeling the effect of gas transport on the formation of defects during thermolysis of powder moldings.  United States.  https://doi.org/10.1557/JMR.1996.0101

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                    Song, J H, Edirisinghe, M J, Evans, J R, and Twizell, E H. 1996.  
        "Modeling the effect of gas transport on the formation of defects during thermolysis of powder moldings".  United States.  https://doi.org/10.1557/JMR.1996.0101.

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@article{osti_280122,

  title        = {Modeling the effect of gas transport on the formation of defects during thermolysis of powder moldings},

  author       = {Song, J H and Edirisinghe, M J and Evans, J R and Twizell, E H},

  abstractNote = {The removal of binder from ceramic or metal moldings by thermolysis involves the transport of degradation products through the parent organic phase and the vacated porous body. A numerical model has been developed to combine an equation which takes into account different gas-flow regimes with an equation for the transport of organic molecules in molten polymers. Computer modeling reveals the critical heating rate above which defects occur due to boiling of the polymer-monomer solution at the center of the molding. The situation in which a porous outer layer of the molding develops, offering resistance to flow of the evolved monomer gas, is then treated. This gives rise to a moving boundary with a variable concentration of diffusant which is dependent on the surface flux, gas transport coefficient and thickness of the porous layer. The contributions of diffusion and viscous flow to gas transport are considered. {copyright} {ital 1996 Materials Research Society.}},

  doi          = {10.1557/JMR.1996.0101},

  url          = {https://www.osti.gov/biblio/280122},
  journal      = {Journal of Materials Research},
number       = 4,

  volume       = 11,

  place        = {United States},

  year         = {Mon Apr 01 00:00:00 EST 1996},

  month        = {Mon Apr 01 00:00:00 EST 1996}

}

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