I am trying to use the resistance spot welder to weld tungsten wire to kovar wire. Presently I am using Nitrogen as inert gas to prevent any oxidation. Is there any other method to obtain good and clean welding joint without using the inert gas?

Susaner

-- Susaner NG (tongng@hk.super.net), July 26, 2003

Answers

A good question. First off, Tungsten to Kovar is a challenge, since the melting temps of Tungsent is 3400 and Kovar 1500. All you can hope to achieve is a solid state bond. Having said that, all metals oxidize to some degree, the question is how much. If you are using a true d.c. power supply, or a high frequency inverter (25KHZ or greater), and the materials are similiar in size, you are doing the best you can with cover gas. On the other hand, if you are using AC or Cap Discharge equipment, you most likely are overheating the materials, and want to trying going to different equipment. Kurt Tolliver, Unitek Miyachi Corp.

-- Kurt Tolliver (kurt@unitekmiyachi.com), July 27, 2003.