An actuator that at least inhibits the deleterious effects of corrosive fluids, such as seawater, does not rely on relatively expensive materials, and is capable of operation and relatively high pressures includes two sealed buffer chambers. One buffer chamber is supplied with a buffer fluid, and the other buffer chamber is maintained at a vacuum pressure. The buffer fluid in the first buffer chamber helps remove any residual corrosive fluid that may remain on the actuator translation member as it moves into the actuator housing, and any fluid that leaks into the second chamber will boil as a result of the vacuum pressure therein.