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Joining Si 3 N 4 ‐Based Ceramics with Oxidation‐Formed Surface Layers
Author(s) -
Plucknett Kevin P.
Publication year - 2000
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2000.tb01662.x
Subject(s) - materials science , sintering , ceramic , amorphous solid , oxide , surface roughness , composite material , surface finish , porosity , inert gas , layer (electronics) , phase (matter) , mineralogy , metallurgy , crystallography , chemistry , organic chemistry
A simple processing technique has been developed for joining Si 3 N 4 ‐based ceramics. Thin (<5 μm thick), amorphous, or partially crystalline SiO 2 ‐based surface layers were formed, via low‐temperature oxidation (at 1200°C), on the faces to be joined. Joining of the surface‐coated pieces could then be performed in an inert environment at typical sintering/joining temperatures (i.e., 1700°C), with or without applied gas pressure, via a transient viscous/liquid phase. This method was most effective for Si 3 N 4 ceramics with single oxide sintering additives when a thin (∼1 μm thick), highly smooth (RMS roughness <60 nm) SiO 2 layer was formed, and essentially ‘pore‐free’ joints could be formed. However, the method was less suitable for a multi‐additive SiAlON material under current experimental conditions, as relatively high roughness (RMS roughness >400 nm) oxide scales formed, leaving residual porosity at the joint interface.