摘要 |
FUSIBLE PORCELAIN IS UNITED IN A THIN LAYER TO A PRECIOUS METAL BASE MEMBER BY FIRST FORMING ON SUCH PRECIOUS METAL BASE MEMBER A GOLD COAT HAVING A CARPET-LIKE, IRREGULAR SURFACE COMPOSED OF GOLD PARTICLES WHICH ARE SOLDERED OR SWEATED TO THE BASE MEMBER AND ARE LATERALLY SEPARATED FROM EACH OTHER, AND THEN APPLYING TO SUCH CARPET-LIKE, IRREGULAR SURFACE A PASTE OF A RELATIVELY LOWFUSING PORCELAIN WHICH UPON BEING FUSED IN SITU IS MECHANICALLY UNITED TO SAID CARPET-LIKE SURFACE BY INTERLOCKING TO SUCH GOLD PARTICLES. THE INTERLOCK THUS FORMED OF THE PORCELAIN LAYER WITH THE PURE GOLD PARTICLES HAS BEEN FOUND TO PERMIT OF LIMITED DIFFERENTIAL EXPANSION AND CONTRACTION BETWEEN THE PORCELAIN LAYER AND THE BASE MEMBER UNDER THE SAME HEAT CONDITIONS DUE TO THE FACT THAT THE PURE GOLD PARTICLES YIELD WITH MOVEMENT OF THE PORCELAIN. THERE IS ALSO PROVIDED TH NOVEL COMPOSITE STRUCTURE OF A PRECIOUS METAL BASE MEMBER, A GOLD COAT LAYER HAVING SPACED GOLD PARTICLES SOLDERED OR SWEATED T THE BASE MEMBER, AND A PORCELAIN LAYER INTERLOCKED TO SUCH GOLD COAT PARTICLES. |