A new copper based hermetic sealing material: A comparison with AgCu28GeCo0.3
For vacuum brazing applications Hermetic Sealing Materials (HSM) with low partial pressure are widely used to join copper or stainless steel parts. For joining copper AgCu28 is a widespread material, which is well characterized and investigated. For stainless steel, AgCu28Ge2Co0.3 is commonly used if the same brazing temperature as AgCu28 is required. Umicore Technical Materials has developed a new copper-based HSM. The tensile strength of the stainless steel joints on stainless steel is comparable to AgCu28Ge2Co0.3 and the wettability is significantly improved. In this article, the physical properties of the alloy and its brazed joints will be presented in comparison to AgCu28GeCo0.3. However, today the silver content of HSMs is more in focus than in the past decades, because it has the biggest impact on the material prices. To accommodate this trend the total silver content of the new HSM is reduced by almost 44 %.
Measurement of contact angle and work of adhesion at high temperature
A critical review is given of the present state of knowledge and future perspectives in high-temperature contact angle measurement. Experimental results obtained by the different versions of the sessile drop method and by various procedures are given in order to illustrate the two main sources of scatter in wettability data, the first being related to the quality of the substrates and the second to control of the furnace atmosphere.
Wettability of zirconium diboride ceramics by Ag, Cu and their alloys with Zr
Abstract Sintered ZrB 2 ceramics, pure and with 4 wt.% Ni as sintering aid, have been tested in contact with liquid Ag, Cu, Ag–Cu and Ag–Cu–Zr. “Pure” ZrB 2 ceramics are wetted by Ag–Zr alloys, and ZrB 2 /Ni ceramics also by pure Cu. The wetting behaviour is briefly discussed in terms of existing wetting theories.