Glass ceramics for sealing to high-thermal-expansion metals

Technical Report · Wed Oct 01 00:00:00 EDT 1980

DOI:https://doi.org/10.2172/6574052· OSTI ID:6574052

Wilder, Jr., J. A.

Glass ceramics were studied, formulated in the Na/sub 2/O CaO.P/sub 2/O/sub 5/, Na/sub 2/O.BaOP/sub 2/O/sub 5/, Na/sub 2/O.Al/sub 2/O/sub 3/.P/sub 2/O/sub 5/, and Li/sub 2/O.BaO.P/sub 2/O/sub 5/ systems to establish their suitability for sealing to high thermal expansion metals, e.g. aluminum, copper, and 300 series stainless steels. Glass ceramics in Na/sub 2/O.CaO.P/sub 2/O/sub 5/ and Na/sub 2/O.BaO.P/sub 2/O/sub 5/ systems have coefficients of thermal expansion in the range 140 x 10/sup -1/ per /sup 0/C less than or equal to ..cap alpha.. less than or equal to 225 x 10/sup -7/ per /sup 0/C and fracture toughness values generally greater than those of phosphate glasses; they are suitable for fabricating seals to high thermal expansion metals. Crystal phases include NaPo/sub 3/, (NaPO/sub 3/)/sub 3/, NaBa(PO/sub 3/)/sub 3/, and NaCa(PO/sub 3/)/sub 3/. Glass ceramics formed in the Na/sub 2/O.Al/sub 2/O/sub 3/.P/sub 2/O/sub 5/ systems have coefficients of thermal expansion greater than 240 x 10/sup -7/ per /sup 0/C, but they have extensive microcracking. Due to their low thermal expansion values (..cap alpha.. less than or equal to 120 x 10/sup -7/ per /sup 0/C), glass ceramics in the Li/sub 2/O.BaO.P/sub 2/O/sub 5/ system are unsuitable for sealing to high thermal expansion metals.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6574052
• Report Number(s): SAND-80-2192; TRN: 81-006712
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM
JOINING
CERAMICS
COPPER
ELECTRON TUBES
SEALS
GLASS
FABRICATION
STAINLESS STEELS
ALUMINIUM OXIDES
BARIUM OXIDES
CALCIUM OXIDES
LITHIUM OXIDES
PHOSPHORUS OXIDES
SODIUM OXIDES
THERMAL EXPANSION
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
ALLOYS
ALUMINIUM COMPOUNDS
BARIUM COMPOUNDS
CALCIUM COMPOUNDS
CHALCOGENIDES
CHROMIUM ALLOYS
CORROSION RESISTANT ALLOYS
ELEMENTS
EXPANSION
IRON ALLOYS
IRON BASE ALLOYS
LITHIUM COMPOUNDS
METALS
OXIDES
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
SODIUM COMPOUNDS
STEELS
TRANSITION ELEMENTS
360601* - Other Materials- Preparation & Manufacture