Corrosion is a common cause of pump degradation across industrial systems handling aggressive fluids and fluctuating operating conditions. Rather than presenting as a single failure event, it typically develops gradually, removing material from critical surfaces and altering flow paths over time.
If left unmanaged, this progressive damage can lead to premature component failure and increased maintenance frequency as a result. Understanding how corrosion initiates and propagates within pump systems is therefore essential for controlling long-term reliability and maintenance costs.
Corrosion arises from a mix of chemical, physical and operational factors. Key causes include:
Understanding the modes of corrosion is vital for engineers to target effective solutions. There are five key types in this respect that need to be considered to maximise component lifespan.
This type affects an entire surface more or less evenly, reducing thickness over time. It is easiest to detect but still detrimental to pump life if not addressed through material selection and coating.
Small but deep holes or pits develop when aggressive ions breach passive films. Pitting is particularly dangerous because it can perforate components with little overall material loss.
Crevices and gaps foster corrosive micro-environments. This often occurs around seals or junctions where fluids can stagnate.
When dissimilar metals are electrically connected in a conductive fluid, the less noble metal corrodes preferentially. This electrochemical reaction can undermine pump internals.
High fluid velocity or particulate load can mechanically erode surfaces while simultaneously promoting corrosion, accelerating degradation far beyond simple chemical attack.
Early detection is a cornerstone of effective corrosion management. Techniques like visual inspection, corrosion probes, ultrasonic thickness testing and electrochemical monitoring are commonly used. Identifying early signs of corrosion (thinning walls, surface pitting, unusual vibration patterns etc.) helps engineers intervene before failure occurs. However, prevention remains one of the most effective strategies in combatting corrosion.
Choosing the right base material is the first line of defence. Austenitic stainless steels, duplex alloys, high-nickel alloys (e.g. Hastelloy) and other corrosion-resistant metals are often specified for aggressive environments, even if they carry a higher initial cost.
In some fluid systems, cathodic protection methods such as sacrificial anodes or impressed current systems help control corrosion electrochemically. Chemical corrosion inhibitors can also slow the reaction rate in certain applications.
Advanced surface engineering, including processes like hard chrome CVD (chemical vapour deposition), applies dense, adherent coatings that significantly enhance corrosion and wear resistance. These coatings add a barrier layer that isolates the substrate from corrosive media while improving surface hardness and fatigue resistance. High-performance metal and ceramic surface layers reduce both general corrosion and localised attack, especially in high-velocity or abrasive environments where traditional coatings may fail.
Corrosion is an unavoidable phenomenon in many pump applications, but its impact can be dramatically reduced through informed engineering choices. From selecting corrosion-resistant metallurgy to applying robust surface protection systems and maintaining vigilant inspection regimes, the right combination of strategies extends pump life, improves reliability and reduces lifecycle costs.
Where surface engineering is critical, advanced coatings that deliver exceptional barrier performance and durability become a key differentiator. Hardide represents a gold-standard solution in this space, offering a proprietary tungsten carbide/tungsten metal matrix composite coating that provides outstanding corrosion and wear resistance across demanding industrial environments. Its ability to protect critical pump components helps engineers extend service life and enhance performance, making it a go-to option where reliability is essential.
To find out more about maximising the lifespan of components facing corrosive environments, download our guide below.