The thermal expansion coefficients of ceramics are generally much lower than metals.
Active metal brazing ceramic.
Our active brazing filler metals enable direct bonding of two ceramics or ceramics to metals regardless of whether they are oxides or nitrides without metallization.
Active metal brazing is a joining method where ceramics can be joined to metals or itself through a brazing alloy known as active brazing alloy aba under the application of heat and pressure.
Depending on joint geometry active metal bonds should not necessarily be considered as strong as moly manganese bonds and may require empirical testing.
Active brazing filler metals our active brazing filler metals enable direct ceramic brazing.
In active metal brazing a metal usually titanium is added to the braze alloy to promote reaction and wetting with a ceramic substrate.
To encourage wetting there are two basic philosophies apply something to the surface of the ceramics so that the braze will wet or put something in the braze that will induce wetting.
Surface treatments include metallisation metal coating and metal hydride treatment while braze modification involves a process known as active metal brazing.
Active brazetm no 10 brazing paste grade b420p 80 provides a silver copper titanium type active brazing filler metal in paste form and is intended principally for brazing non metallised alumina ceramics to a metallic substrate.
Ceramic brazing with metallic fillers utilizes either premetallized ceramic surfaces or braze foils pastes or wires that usually contain a reactive filler metal such as ti which promotes braze wettability and flow characteristics by inducing chemical reactions with the ceramic.
One step brazing with aba replaces metallising firing and electroplating offering savings in time and cost.
Active brazing alloys active brazing alloys aba eliminate the need for traditional ceramic metallisation prior to brazing as the active components promotes wetting on the ceramic surface.
Therefore the type and concentration of the added active element in the brazing alloy are crucial to the joint strength.
When joining ceramics to metals with the brazing method for example metallization on the ceramic surface is necessary with general inactive brazing filler metal or the use of active brazing alloys in order to get a reliable joint.
