Brazing titanium-vapor-coated zirconia

Journal Article · Thu Apr 01 04:00:00 EST 1993 · Welding Journal (Miami); (United States)

OSTI ID:6518840

Santella, M L ^[1]; Pak, J J ^[2]

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1. Oak Ridge National Lab., TN (United States)
2. Pohang Steel Co. (Korea, Republic of)

Partially stabilized zirconia was vacuum furnace brazed to itself, to nodular cast iron, and to commercially pure titanium with a Ag-30Cu-10Sn wt% filler metal. Wetting was obtained by coating the ZrO[sub 2] surfaces with Ti prior to brazing by RF sputtering or electron beam evaporation. Braze joints made with Ti-sputter-coated ZrO[sub 2] contained high levels of porosity, but those made with Ti coatings deposited by evaporation, referred to as Ti-vapor-coated, contained little or no porosity. Brazing caused the ZrO[sub 2] within about 1 mm (0.04 in.) of the joint surfaces to turn black in color, and thermodynamic analysis indicated that the discoloration was likely due to oxygen diffusion out of the ZrO[sub 2] into the Ti vapor coating during brazing. Braze joint strength was determined by flexure testing in the four-point bend arrangement, and on a more limited basis, by shear testing. The latter method was used mainly as a screening test for ZrO[sub 2]-Fe and ZrO[sub 2]-Ti joints. Flexure testing of ZrO[sub 2]-ZrO[sub 2] and ZrO[sub 2]-Fe braze joints was done at 25, 200, 400, and 575 C (77, 392, 752 and 1,067 F) in air. For flexure testing, average strengths of joint specimens decreased with increasing test temperature. The lower average strengths of ZrO[sub 2]-Fe specimens compared to those from ZrO[sub 2]-ZrO[sub 2] joints was attributed to higher residual stresses in the ceramic-to-metal joints.

• OSTI ID: 6518840
• Journal Information: Welding Journal (Miami); (United States), Journal Name: Welding Journal (Miami); (United States) Vol. 72:4; ISSN 0043-2296; ISSN WEJUA3
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360203 -- Ceramics
Cermets
& Refractories-- Mechanical Properties
ALLOYS
BRAZED JOINTS
BRAZING
BRAZING ALLOYS
CHALCOGENIDES
COATINGS
CRYSTAL STRUCTURE
ELEMENTS
FABRICATION
FRACTURE PROPERTIES
IRON
JOINING
JOINTS
MECHANICAL PROPERTIES
METALS
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
POROSITY
SPUTTERING
SURFACTANTS
TITANIUM
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
VAPOR DEPOSITED COATINGS
WELDED JOINTS
WELDING
WETTING AGENTS
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES