摘要 |
<p>In order to silver braze a ceramic heating element (6), a metallic outer sleeve (8) and an electrode fitting (14) together, optimum conditions are confirmed by tests so as to prevent an occurrence of an electrical short-circuit between the metallic outer sleeve (8) and the electrode fitting (14). When heated to 900 °C in hydrogen ambient, a silver brazing filler metal melts and flows into interstices between the outer peripheral surface of the ceramic heating element and the inner peripheral surface of the metallic outer sleeve and into interstices between the attachment opening in the ceramic heating element and the external surface of the electrode fitting. When an internal diameter X of the metallic outer sleeve and an external diameter Y of the electrode fitting satisfy the relationship X - Y ≥ 1.5 mm, there remains no silver brazing filler metal (22) on the ceramic heating element (6).</p> |