Chapter 52. Sealing 304L to Lithia-Alumina-Silica (LAS) Glass-Ceramics

  1. John B. Wachtman Jr.
  1. W. E. Moddeman1,
  2. R. E. Pence1,
  3. R. T. Massey1,
  4. R. T. Cassidy1 and
  5. D. P. Kramer2

Published Online: 28 MAR 2008

DOI: 10.1002/9780470310588.ch52

A Collection of Papers Presented at the 13th Annual Conference on Composites and Advanced Ceramic Materials, Part 2 of 2: Ceramic Engineering and Science Proceedings, Volume 10, Issue 9/10

A Collection of Papers Presented at the 13th Annual Conference on Composites and Advanced Ceramic Materials, Part 2 of 2: Ceramic Engineering and Science Proceedings, Volume 10, Issue 9/10

How to Cite

Moddeman, W. E., Pence, R. E., Massey, R. T., Cassidy, R. T. and Kramer, D. P. (1989) Sealing 304L to Lithia-Alumina-Silica (LAS) Glass-Ceramics, in A Collection of Papers Presented at the 13th Annual Conference on Composites and Advanced Ceramic Materials, Part 2 of 2: Ceramic Engineering and Science Proceedings, Volume 10, Issue 9/10 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470310588.ch52

Author Information

  1. 1

    EG&G Mound Applied Technologies Miamisburg, OH

  2. 2

    EG&G Electronic Components Division Albuquerque, NM

Publication History

  1. Published Online: 28 MAR 2008
  2. Published Print: 1 JAN 1989

ISBN Information

Print ISBN: 9780470374870

Online ISBN: 9780470310588

SEARCH

Keywords:

  • ceramics;
  • ion beam energy:;
  • aluminum oxide;
  • metallization;
  • aluminum nitride

Summary

The formation of a crack-free seal between a 300 series stainless steel and a glass-ceramic has in the past been very difficult. The primary cause of this difficulty has been in obtaining glass-ceramic compositions whose coefficient of thermal expansion (CTE) approaches that of the 300 series metal piece parts. Stainless steels of the 300 series have very high CTE values that range from 180-220 × 10−7 cm/cm/°C (RT-300°C). Therefore, the corresponding glass-ceramic should have a similarly high CTE to enable the formation of stress-free seals. Both at EG&G Mound and at EG&G Electronic Components, lithia-alumina-silica (LAS) glass-ceramics have now been successfully developed and sealed to 304L stainless steel. These crack-free seals have been routinely fabricated using two techniques: by adjusting the parent glass composition or by adjusting the sealing/crystallization (or sealing/devitrification) cycle that is routinely used in forming seals between LAS glass-ceramic and nickel-based alloys. All seals were determined to be hermetic, with leak rates of <10−8 cc/sec of STP helium. Additional data on CTE values and alloy yield strengths will be given which show the feasibility of using these materials in the manufacture of various components including feedthroughs and pyrotechnic components. Metallography, SEM, and wavelength dispersive spectroscopy (WDS) results show the quality and the integrity of the glassceramic/stainless steel interface. Whenever possible, these data are compared to similar studies accomplished in the Inconel 718/LAS-glass seal system.