Melt processing of optical alumina fibers: A process review and product outlook

Journal Article · Wed Jan 01 04:00:00 EST 1992 · SAMPE Quarterly (Society of Aerospace Material and Process Engineers); (United States)

OSTI ID:5385890

Wallenberger, F T ^[1]; Brown, S D ^[2]; Koutsky, J A ^[3]

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1. DuPont Fibers, Wilmington, DE (United States)
2. Univ. of Illinois, Urbana (United States)
3. Univ. of Wisconsin, Madison (United States)

X-ray amorphous, calcium aluminate glass fibers can be made by one of three melt processing methods. Selected amorphous fibers with 23-47% Al{sub 2}O{sub 3} have high melt viscosities and can either be drawn from supercooled melts or spun above the liquidus through an orifice. The vast majority of fibers, especially those with 50-100% Al{sub 2}O{sub 3}, have low viscosities and can only be made by inviscid melt spinning. As-spun fibers with 50-81% Al{sub 2}O{sub 3} were x-ray amorphous and strong, but polycrystalline and weak with 82-100% Al{sub 2}O{sub 3}. This review also provides new insights regarding a wide range of structure/property relationships so that fibers with a desired set of properties can be designed before they are made, and that an appropriate fabrication process can be selected. High melt viscosities in the alumina-calcia system which support drawing fibers from supercooled melts were believed to require the presence of silica (> 3.5%), but recent work shows that silica is not necessarily required as a viscosity builder. Melt viscosity and amorphous fiber modulus are primarily rheology controlled but somewhat limited by compositional factors. The chemical jet stabilization mechanism in the inviscid melt spinning process is also rheology controlled; particulate carbon from the decomposition of propane enters into the surface of the molten jet, raises the surface viscosity and stabilizes the jet which would otherwise deteriorate and form Rayleigh waves and droplets.

• OSTI ID: 5385890
• Journal Information: SAMPE Quarterly (Society of Aerospace Material and Process Engineers); (United States), Journal Name: SAMPE Quarterly (Society of Aerospace Material and Process Engineers); (United States) Vol. 23:2; ISSN 0036-0821; ISSN SAMQA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360601* -- Other Materials-- Preparation & Manufacture
360603 -- Materials-- Properties
ALKALINE EARTH METAL COMPOUNDS
ALUMINATES
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AMORPHOUS STATE
CALCIUM COMPOUNDS
CALCIUM OXIDES
CARBON
CHALCOGENIDES
CHEMICAL COMPOSITION
COMPOSITE MATERIALS
CRYSTALS
DENSITY
DIAGRAMS
ELEMENTS
FABRICATION
FIBERS
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MATERIALS
MECHANICAL PROPERTIES
MELTING
MINERALS
NONMETALS
OPTICAL FIBERS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
POLYCRYSTALS
QUANTITY RATIO
REINFORCED MATERIALS
RHEOLOGY
SILICA
SILICON COMPOUNDS
SILICON OXIDES
STABILIZATION
TECHNOLOGY ASSESSMENT
TENSILE PROPERTIES
VISCOSITY