Metal-ceramic adhesion: Synthesis of aluminum and chromium mixed metal oxides and extended Hueckel modeling of metal-metal oxide interfaces

Miscellaneous · Fri Jan 01 00:00:00 EST 1993

OSTI ID:7182086

Boorse, R S

Methods of chemical synthesis and theoretical calculation was used to form new materials that have improved adhesion of a thin metal film to a ceramic. Two goals of this investigation were to develop new synthesis of metal-ceramic couples with improved adhesion between the two components and a fundamental understanding of the chemical factors that affect adhesion. Extended Hueckel calculations were performed on a series of Pt- and NiPt-NiO metal-ceramic couples to examine bonding. The calculations showed an 5 fold increase in adhesion energy in NiPt-NiO over Pt-NiO. Bonding across the interface is found to decrease with increased electron donation as interfacially antibonding orbitals are filled. The synthesis of (Al[sub 1[minus]x]Cr[sub x])[sub 2]O[sub 3] mixed metal oxide powders and coatings by sol-gel methodology utilizing three chromium precursors is reported. Thus, Al[Cr(CO)[sub 3]C[sub 5]H[sub 5]][sub 3]. THF[sub 3], Cr(OBu[sup t])[sub 4], and CrO[sub 3] were used with Al(OBu[sup s])[sub 3] to form clear, water- or alcohol-based sols, films and xerogels across the entire composition range (0[le]x[le]1). Carbon resonance RBS indicated the removal of most carbon from alcohol-based, sol-derived coatings that had been prepared by microwave treatment and calcination at 500[degrees]C. Using Cr(acac)[sub 3] as a precursor, deposition of chromium oxide onto silicon and Al[sub 2]O[sub 3] by MOCVD produced 800 [angstrom] to 2 [mu]m thick films. Deposition at 350[degrees]C under O[sub 2] produced smooth films containing crystalline Cr[sub 2]O[sub 3] but whose stoichiometry covered a range, Cr[sub 2]O[sub x] (3.2[le]x[le]4.9). Cr[sub 2]O[sub 3.5] films did not lose oxygen upon firing at 1100[degrees]C, but were converted to epitaxial Cr[sub 2]O[sub 3] at 1300[degrees]C. Micromechanical adhesion testing of chromium metal overlayers to sol-derived coatings reflected the ten-fold increase in adhesion on going from alumina to chromia.

• Research Organization: Cornell Univ., Ithaca, NY (United States)
• OSTI ID: 7182086
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALUMINIUM OXIDES
ADHESION
CHEMICAL PREPARATION
COMPATIBILITY
CHROMIUM OXIDES
METALS
CERAMICS
INTERFACES
NICKEL
PLATINUM
SOL-GEL PROCESS
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CHROMIUM COMPOUNDS
ELEMENTS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
360203* - Ceramics
Cermets
& Refractories- Mechanical Properties
400201 - Chemical & Physicochemical Properties