Vapor phase corrosion protection is an important factor to consider when adding corrosion inhibitors to hydraulic fluids. Traditional corrosion inhibitors typically protect only the metals directly in contact with the corrosion inhibiting fluid. This ignores the vulnerable metal surfaces in the surrounding void space above the level of the hydraulic fluid.
Protection of these areas is especially important where layup, storage, or shipment is concerned, since at least partial draining of fluids is often preferred. For maximum protection with a contact-only corrosion inhibitor, areas such as hydraulic fluid reservoirs must be completely filled with corrosion inhibiting hydraulic fluid. However, this method can be costly and may still not be fully effective for void space inevitably remaining at the very top of the tank.
A more cost-effective and successful option is incorporating Vapor phase Corrosion Inhibitors (VpCIs) into hydraulic fluids where void space protection is needed. These corrosion inhibitors protect both the metal in contact with the fluid and metal surfaces above the fluid. When used, the amount of hydraulic fluid needed during storage or shipment can often be reduced at the same time protection is enhanced. This saves on fluid usage and prevents cumbersome draining, clean-up, or rust removal after storage, making protection easier and more cost-effective.
One way to find out whether or not a hydraulic fluid includes vapor phase protection is to test the fluid according to ASTM D-5534 “Standard Test Method for Vapor-Phase Rust-Preventing Characteristics of Hydraulic Fluids.”
As part of its ISO 17025 accreditation, Cortec® Laboratories is certified to perform this testing, which is a pass/fail evaluation of vapor corrosion inhibiting effectiveness for both water-based and oil-based hydraulic fluids. The test consists of exposing a steel disc to water and hydraulic fluid vapor in a beaker at an elevated temperature for several hours. At the end of the test, the steel disc is examined for rust to determine if the product either passes or fails.
As the only ISO 17025 Accredited lab in the industry, Cortec® Laboratories is a leader in providing corrosion testing services that help end users select the best product for their applications. Through decades of research, testing, and practical experience, Cortec® has amassed a wealth of corrosion control knowledge, as evidenced by the industry’s largest portfolio of 63 patents issued over the course of 40 years. Cortec® is eager to share this expertise by helping end users find innovative solutions in their search for effective corrosion control.
Cortec® recommends considering the vapor phase protection ability of hydraulic fluids before storage or shipment of equipment containing hydraulic fluids in void spaces. By choosing a hydraulic fluid with a Vapor phase Corrosion Inhibitor, users will be able to provide greater protection against corrosion in a more cost-effective, practical way.