Category Archives: Application & Performance

Brazing of titanium, ceramics, and graphite using new low-temperature Ti- and Zr-based amorphous foils

Applications of new brazing filler metals in the form of amorphous foils 50 microns thick, and 75 mm wide for vacuum brazing of titanium alloys, graphite, and ceramics are discussed in the paper. Brazed joints were evaluated by testing strength, microstructures, and sometimes phase compositions of base and filler metal interfaces. The following amorphous foils were tested: (a) TiBraze®200 (Ti-20Zr-20Cu-20Ni wt.%) with the melting range of 845-863°C (1553-1585°F), (b) TiBraze®590 (Zr-17Ti-20Ni-1Hf wt.%) with the melting range of 796-813°C (1465-1495°F), and (c) TiBraze®800 (Zr-14.7Ti-12.6Ni-7Cu-1Hf wt.%) with the melting range of 772-786°C (1422-1447°F).
Shear strength of brazed joints of CP titanium and Ti-6Al-4V alloy with copper, stainless steel 304, and Ni-plated carbon steel are reported, as well as microstructures of joints studied after brazing at different temperatures. Brazing temperatures of titanium joints with amorphous foils are significantly lower than that of standard filler metal AWS BTi-1 (Ticuni®). Brazing of titanium-to-ceramics and graphite with new foils should be done at temperatures greater by 50-60°C than that of brazing titanium-to-titanium. If compared to traditional active brazing filler metals which do not spread on ceramic surfaces, the tested Ti- and Zr-based amorphous foils revealed excellent wetting, and sometimes spreading, along ceramic surfaces of alumina and boron nitride, as well as graphite. Also, all samples of fin-plate titanium heat exchangers and honeycomb panels brazed with amorphous foils displayed good quality of the brazed joints.

Silicon Carbide (SiC) to Metal Joining

As the cost of producing SiC ceramic and as the technology to “cast” complex parts with SiSiC composite ceramics matures, there is increasing applications for bonding SiC based ceramics to metals. Applications are expanding in electronics (LED’s and semiconductors), optical mirrors, energy production and aerospace.           The challenge in many of […]

Sapphire to Metal Hermetic Seals

We get many calls about hermetically sealing sapphire (single crystal aluminum oxide) to metal flanges and this post addresses some of the applicable commercial methods used.  Sapphire to metal seals many times are used in sensor housing like those seen in Figure 1. In this application these titanium housing are actively soldered (S-Bond) to the […]

Service Conditions and Ceramic: Metals Joint Behavior

177226931Ceramic:metal bonding is done in many applications from propulsion and turbine components, electronic packaging, electrical power components, batteries, sensors, sensor housings, wear inserts, medical surgical components, insulating feeds, etc. These varied applications also mean widely varying performance requirements and service conditions. This lead off discussion thread is to get us all thinking about performance and service and to present materials, design and commercial solutions that have been considered, used… offering case studies or other articles that permit our community insight into issues and solutions.

To get this discussion started I will highlight function and considerations in selecting ceramic:metal bonding.