Zinc-Free Hydraulic Fluid Additives: Performance Without Compromise

Why Choose a Zinc-Free Hydraulic Fluid Additive?

While zinc is a common component of anti-wear hydraulic fluids, the metal can complicate waste handling. Without zinc, used oil faces fewer restrictions in recycling streams, and the risk of metal contamination in soil and water decreases. This can simplify compliance and lower disposal costs over the fluid life cycle. Zinc-free additive systems provide lubricity and anti-wear protection that generate protective boundary films under high load and temperature. These chemistries employ phosphorus and sulfur donors to achieve wear control comparable to traditional ZDDP without introducing zinc-derived ash.

Environmental considerations have historically driven the adoption of zinc-free hydraulic fluids, but in recent years, original equipment manufacturers (OEMs) have recognized advantages beyond their environmental profile. Modern hydraulic equipment is operating at higher temperatures. Under high-temperature or oxidation conditions, zinc can react with oxygen and eventually form ash or sludge. Zinc-derived ash or sludge can build up, clogging filters and shortening oil life. Newer systems increasingly incorporate yellow metals, such as copper and brass, and require fluid compatibility to minimize yellow metal corrosion and staining. Yellow metals tend to corrode in the presence of zinc oxides, making ZDDP problematic in some applications.

Advances in zinc-free chemistry also bring clear performance advantages. Zinc-free hydraulic additives have demonstrated stronger high-temperature stability and oxidation performance, leading to longer fluid life and service intervals. Afton has seen nearly twice the performance with zinc-free fluids in the A2F10 pump test. For high-stakes applications, many OEMs prefer zinc-free fluids for longer drain intervals, which reduce fluid consumption and costly downtime and improve total cost of ownership.

Applications that benefit most include marine and port equipment with tightly controlled discharge risks; facilities that demand cleaner additive profiles; environmentally sensitive operations such as forestry, construction, mining, or utility right-of-way maintenance; and closed-loop systems that require exceptional cleanliness to protect servo valves and high-pressure pumps. In each case, a zinc-free hydraulic fluid helps reduce risk while improving productivity.

HiTEC^® 55300 Premium Zn-Free Hydraulic Package

HiTEC^® 55300 hydraulic additive package is Afton's newest zinc-free offering, engineered to deliver superior wear protection, oxidation stability, and sludge control in demanding hydraulic systems. It provides robust anti-wear performance without ZDDP, helping protect pumps, motors, and precision valves under high pressures.

The additive package is capable of meeting major performance specifications, including Bosch Rexroth, Parker HF-0, Danfoss/Eaton, and relevant DIN categories when formulated in qualified base oils. It supports both monograde and multigrade formulations across key viscosity grades.

HiTEC^® 55300 zinc-free additive package helps keep systems clean, supports longer service intervals, and enhances reliability in sensitive industrial hydraulic applications. Interested in exploring zinc-free alternatives? Contact us today to speak with a technical representative and request a sample!