Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


case1061910390.pdf (3.17 MB)

ETD Abstract Container

Abstract Header

Composite and microcomposite fabrication via depletion stabilization routes

Wernet, Judith Hedwig
http://rave.ohiolink.edu/etdc/view?acc_num=case1061910390

Abstract Details

1995, Doctor of Philosophy, Case Western Reserve University, Chemical Engineering.
The colloidal phenomena of depletion stabilization and flocculation can be used to prepare high solids content slips with good fluidity. In this work these methods have been utilized as processing techniques to provide a controllable means by which monolayer and thicker coatings of matrix powder can be applied to fibers. External control of the particle-particle interactions dominating the stability of these slips reflects directly in the quality of the fiber coatings. As a result, ideal processing conditions for optimal coatings of fibers can be identified. Uniform coatings of up to 6 μm thick on AVCO SCS-6 fibers have been produced from slips of 0.07-0.3 μm diameter Si powder prepared using depletion strategies. The technique is effective even for asymmetric particle shapes (e.g. angular platelets) and wider size distributions. However, more uniform shapes and smaller size distributions were observed to result in dramatically improved, densely packed coatings.Optimum processing conditions with maximum slurry solids loading and maximum particle-particle stability obtained using the depletion stabilization phenomena were scaled up for fiber weave infiltrations. Infiltrated weaves were cold and hot pressed and nitrided to enable evaluation of the infiltration quality via SEM examination of cross sections of the infiltrated weaves. High quality Nicalon square and satin weave infiltrations were achieved using the depletion stabilization colloidal processing technique. Nitrided weave cross sectional samples showed a uniform infiltration of silicon powder throughout the matrix. A variety of additional weave styles and fiber types were infiltrated to determine the robustness of the technique. These weave styles were similarly uniformly infiltrated throughout. An analysis was performed on the coating of a non-Newtonian fluid onto a vertical fiber surface continuously withdrawn from the fluid bath. The fiber coating thickness was determined to be a function of the fiber pulling speed, the fluid density and the parameters of the viscous model of the silicon slurry used. The analytic treatment also predicts the velocity profile of the fluid on the fiber surface in the region of constant coating thickness as a function of fiber pulling speed. The penetration of the slurry into a fiber bundle was also analyzed. The approximate penetration was estimated using the non-Newtonian fluid properties and fiber bundle parameters
Donald Feke (Advisor)
134 p.
Engineering, Chemical
Composite/Microcomposite fabrication; Depletion stabilization

Recommended Citations

Citations

  • Wernet, J. H. (1995). Composite and microcomposite fabrication via depletion stabilization routes [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1061910390

    APA Style (7th edition)

  • Wernet, Judith. Composite and microcomposite fabrication via depletion stabilization routes. 1995. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1061910390.

    MLA Style (8th edition)

  • Wernet, Judith. "Composite and microcomposite fabrication via depletion stabilization routes." Doctoral dissertation, Case Western Reserve University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=case1061910390

    Chicago Manual of Style (17th edition)

case1061910390
483
© 1995, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.