Question

Why a platinum wire can be safely sealed into a soda lime glass?

Answer 1

Platinum has got a comparatively lower thermal conductivity of 71.6 W.m−1.K−1 thus it cannot draw heat quickly away from the site of its fusion into hot soda-lime glass and the glass does not break because of local cooling. But if copper is sealed into soda-lime glass it will break while cooling because of copper’s high thermal conductivity.

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