During a vacuum processing cycle various chemical reactions can occur in a vacuum furnace that can cause a “metallurgical meltdown,” according to the authors of a new paper on the subject, entitled Preventing Eutectic Reactions and Diffusion Bonding in Vacuum Processing.
The article discusses how eutectic compositions can form while heat treating, and how diffusion bonding can be a concern to heat treaters when two dissimilar materials are in close contact with each other in high vacuum at elevated temperatures. In the paper, different methods of preventing these reactions are examined.
“The best way to think of a eutectic is a metallurgical meltdown,” wrote the experts from Solar Atmospheres in Souderton, Pennsylvania.
When the two components with different melting points and surfaces free of oxides come in contact with each other in the vacuum furnace the reactions can occur, according to the authors.
“This can create an atomic diffusion. For some materials, when a specific atomic composition is reached, they will melt at a temperature much lower than the melting point of the individual metals. If that temperature is reached or exceeded during the heat treating cycle, melting will occur at the contact points. This is referred to as a eutectic melt.”
To view the full article, visit https://solaratm.com/tech-downloads/preventing-eutectic-reactions-and-diffusion-bonding-in-vacuum-processing.
Related Glossary Terms
- diffusion
diffusion
1. Spreading of a constituent in a gas, liquid or solid, tending to make the composition of all parts uniform. 2. Spontaneous movement of atoms or molecules to new sites within a material.
- eutectic
eutectic
1. Isothermal reversible reaction in which a liquid solution is converted into two or more intimately mixed solids on cooling, the number of solids formed being the same as the number of components in the system. 2. Alloy having the composition indicated by the eutectic point on an equilibrium diagram. 3. Alloy structure of intermixed solid constituents formed by the eutectic reaction.
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