6 Things You Need to Know About Platinized Titanium Anodes (1)
Comparing the two types of cathodic protection (CP), sacrificial anode cathodic protection (SACP) uses sacrificial anodes made of a material that is less noble than the structure being protected and is gradually consumed. In contrast, impressed current cathodic protection (ICCP) uses an external current source with a generally very low or non-consumable anode. Various materials have been used for ICCP systems, but new material combinations are showing promise for many applications.
#1: Combining Platinum and Titanium for Outstanding Corrosion Prevention
Platinized titanium anodes synergistically combine the favorable electrochemical features of platinum (Pt) with the corrosion resistance and other characteristics of titanium. They are anodes normally produced by the electrochemical deposition of a skinny layer of platinum metal or the oxides of platinum onto a titanium substrate. These anodes operate as inert anodes with high durability and are preferred because they remain insoluble in common electrolytes.
Platinum is a precious metal known for its unique favorable attributes, including:
High resistance to corrosion
Resistance to oxidation
High electrical conductivity
Ability to act as a catalyst
High chemical stability
Capability to produce an excellent finish
The low consumption rate backed by high electrical conductivity makes platinum a preferred anode substance. But because of its high cost, only a thin layer of platinum is typically plated on different corrosion-resistant materials such as tantalum (Ta), niobium (Nb), or titanium (Ti) to take advantage of these favorable features.
By electroplating the platinum metal on titanium, a composite metallic coating can also be produced on the substrate. (Learn more about this process in How Metallic Coatings Protect Metals from Corrosion.) This composite consists of titanium metal, platinum, oxides of titanium, and metallic compounds of titanium and platinum. The process of heat treating the composite coating produces changes in chemical composition and morphology that improve its electrochemical properties.
The adoption of platinum-plated and platinum-cladded anodes has provided additional novel options and choices to designers of impressed current cathodic protection (ICCP) systems, because the additional benefits offered by anodes made of composites of platinum on titanium and platinum on tantalum are game changers in the corrosion protection industry, thus enabling their widespread adoption.
Galvanic materials generally used in anodes, such as magnesium and zinc, are not preferred materials because they are bulky, expensive to maintain, and must be replaced frequently.
(To be continued)
