When bonded with metals, including stainless steel and aluminum, silicon forms an air tight bond between the two materials that is not likely to contaminate or wear over time. Silicon is also an inert material, meaning it will not react chemically or physically when in contact with any other liquid, solid or gas substance.
Silicon is a rubber bonded to metal that is used most often for medical applications in hospitals, operating rooms and doctor offices. They make excellent handles for medical instruments, specifically for those used in surgical situations. When bonded, the spot where the metal and silicon meet have almost no risk of contamination because no substance is able to penetrate the cracks.
Because of its extreme resistance to heat, silicon can withstand regular autoclave sterilization cycles, which is necessary for all reusable medical tools. Silicon bonded metal is also used in blood analysis, in medical machinery and for any use that would require a graspable handle that should also be able to come into contact with human fluid or high heat.
The silicon rubber to metal bonding process is simple, but takes over an hour to fully complete. When bonded with aluminum, a specialty adhesive for longer lasting durability is necessary, but often this bonding process requires no adhesive because silicon is known for its excellent adherent and bonding qualities.
First, the metal part or product is heat treated in an oven between 500° to 600° F for just under an hour. This forms an oxide layer on the metal’s outer surface, which turns it a different color. It is allowed to cool and then the metal is coated evenly with a primer. Then, uncured and liquid silicon is filled inside a mold with the exact measurements of the instrument’s handle cover.
The metal part is submerged into the silicon rubber composition, which then cures around it. Once cured, the silicon hardens and tightly adheres to the metal component. This process is often done in high volumes to manufacture many silicone bonded products at once. The results are durable, long lasting medical products and instruments ready to handle any application within a hospital setting for years to come.