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Soldering with no flux

In most common way of soldering, a flux may be needed and at IJ Research often uses no flux. We call the process as a soldering with no flux or flux-less soldering.

Our unique flux-less soldering at IJ Research can be used virtually with any/all solders regardless what the recommended soldering temperature is and what kind of soldering material is.

The soldering similar to brazing is a metallurgical wetting process and the wetting will be occur when there is a high enough temperature and there is no oxidation on all the three mating parts; Part I and Part II to put together and the solder itself in-between throughout the process.

Surfaces of each part need to be oxidation free during the soldering and as-prepared parts; they should be free of oxidation as much as they can be. In general except precious metals, many of the metals are not stable in our standard condition and naturally form a layer of oxidation on their surfaces. More surface more oxidations. The surfaces need to be protected all time from the naturally occurring oxidations. Simple bagging will certainly help since we have a sufficient amount of oxygen in air for this oxidation. Once a soldering is completed, the solder joint should be free of stress entrance points. A simple contact angle test shall tell you if the processing condition was sufficiently adequate for a good metallurgically wet seal.

Soldering is a brazing but it is called soldering if the brazing is done below 450OC and it will be called brazing if it is done at higher than 450OC. How to braze is basically the same as how to solder except the temperature to use. Utilizing the basic metallurgical properties, IJ Research solders them with no use of flux.

Storing the parts and consumable materials in a clean oxygen free or oxygen poor chamber as a routine precaution works and supports the principle requirement for the flux-less soldering. Less oxidation and less contamination will offer less work in having the proper condition of a flux-less soldering.

Using a flux is not bad idea as long as you can control to take the entire flux out after the process is done without leaving any residue of the flux. As long as the excess flux comes on top of the joint or soldered assemblies, you might be able to remove using an appropriate solvent.

IJ Research sometime uses an inert gas chamber for storage as well as for actual processing.

IJ Research has been well known for certain critical parts, mostly optical window cap assemblies (including various lenses) for high vacuum and sensitive corrosion resistance field. The sealing the window with a flange at a lower temperature in some cases is a mandate to prevent any heat damage on the window or lens. Some of the windows such Ge, ZnS, etc. must be sealed at a low temperature. A high temperature window such as fused silica or quartz can take high heat but for a hermetic seal with a flange needs to seal at a low temperature. IJ Research is a qualified vendor for many customers.

One of the key requirements is the metallization on the window. How to metalize on Ge is very important process requirement of the seal and IJ Research is a qualified vendor for our customers. The metallization quartz is important one, too. ZnS is one of the tough one, too. Subsequent soldering often delaminates the metallization from the thermal vibration.

IJ Research prepares the surface of the window for flux-less soldering. IJ Research of course prepares the metal flange for such soldering. Our in-house systems are so process effective. Often we skip the Au from our metallizations leading cost effective and high quality parts with no Au leaching.

Other reference Corporate Literature you might be interested in reading is Thin Film and Metallization.

Please contact IJ Research using 1-714-546-8522 or [email protected].