Powder metal components have an excessive amount of porosity due to the inherent method used in manufacturing. Vacuum impregnation is the preferred solution to seal powder metal porosity. There are three main reasons why powder metal parts are sealed through vacuum impregnation.
Preventing Fluids or Gases from Leaking Under Pressure
If the components are not sealed, then fluids or gases will leak from the part. Vacuum impregnation prevents fluids or gases from leaking by sealing the porosity and leak paths. The process does this without changing the powder metal components dimensional or functional characteristics.
Reduce Internal Corrosion
Powder metal parts are sealed prior to plating to reduce internal corrosion. Plating operations involve submerging the components in acid solutions. The residual acid can seep into the porosity which will cause corrosion. Sealing the components through vacuum impregnation will seal the porosity. Vacuum impregnation allows the exterior powder metal surfaces to be plated or painted, delivering a superior secondary finish.
Powder metal parts are also impregnated to enhance machinability. Secondary machine operations, such as drilling, tapping or cutting are only marginally successful because voids between the particles cause tool chatter, reducing tool life and finish quality. Vacuum impregnation serves as a combination lubricant, stabilizer and support for individual powdered metal granules. After impregnation, machining is far more efficient, tool chatter is eliminated and the machined finish is greatly improved.
Vacuum impregnation adds value to powdered metal components by preventing leaking, reducing internal corrosion, and enhancing machinability. We invite you to download our Vacuum Impregnation eBook. This free eBook will expand your knowledge on porosity and vacuum impregnation.