Screen-printing of 1720 and 7059 glass insulating bonds for the radioisotopic thermoelectric generator

Technical Report · Sat Dec 01 00:00:00 EST 1973

DOI:https://doi.org/10.2172/4381561· OSTI ID:4381561

Jennings, C W

As part of the RTG fabrication sequence, Si/Ge and Si/Ge-glass substrates are coated with Corning 1720 and 7059 glass by a screen-printing process. A slurry of glass, pine oil, and terpinol is printed, followed by a burnout of the organic matter in oxygen at 500 deg C. It has been determined from overall fabrication considerations that there should be sufficient glass present to yield a fused-glass thickness of 1.2 to 1.4 mils. Glass content of the slurry, screen size, squeegee pressure, and breakaway distance are the important parameters affecting the amount of glass printed. Less variability in glass thickness is experienced when the screen contacts the substrate during printing. This occurs at higher squeegee pressures. The desired glass thickness is achieved by adjusting the glass content of the slurry to the screen mesh size, i.e., less glass is needed for an 80-mesh screen than for a 105mesh screen. Not all of the slurry is retained on the substrate during printing; the fraction adhering to the screen is a function of the breakaway distance. Moderate slurry viscosity and temperature changes during screen printing have only minor effects on the thickness of the glass deposited. Routine printing of 1720 and 7059 glass slurries with 65- and 70-% glass have consistently yielded glass thicknesses between 1.2 and 1.4 mils. (auth)

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AT(29-1)-789
• NSA Number: NSA-29-012655
• OSTI ID: 4381561
• Report Number(s): SLA-73-80
• Resource Relation: Other Information: Orig. Receipt Date: 30-JUN-74
• Country of Publication: United States
• Language: English

Related Subjects

N42100* -Engineering-Energy Conversion
N50120 -Metals
Ceramics
& Other Materials-Ceramics & Cermets-Preparation & Fabrication
*GLASS- COATINGS
*THERMOCOUPLES- FABRICATION
*THERMOELECTRIC GENERATORS- THERMOCOUPLES
BONDING
DIELECTRIC MATERIALS
GERMANIUM
RADIOISOTOPE HEAT SOURCES
SILICON
NESDPS Office of Nuclear Energy Space and Defense Power Systems