In this interview, Earl W. Ramlow, Product Manager, Polyset, describes the uses of a WaterBorne High Ratio Zinc Silicate coating system, including in US Navy and US Army causeway watercraft systems.
What is a WB HRZS® coating system?
WB HRZS® (WaterBorne High Ratio Zinc Silicate) is a previously NASA-patented, high performance coating system that offers unparalleled corrosion protection for steel structures in a variety of industrial and commercial applications. The most unique feature of this product is that it forms a true chemical bond with the steel substrate and therefore will never undercut. WB HRZS® is also a green technology that is 100% waterborne (0 VOC) and can be used as a Single Coat System, Primer or Pre-Construction Primer.
WB HRZS® is a two-component system consisting of Part A (liquid binder) and Part B (zinc dust). After adding Part B to Part A, the mixed product is spray-applied to the prepared substrate and a solid, zinc-infused ceramic film is created due to the reaction between the silicate in the binder and the iron in the steel. Combined with evaporation of the water out of the binder, this results in an insoluble and chemically bonded coating system comprised of silicon to iron bonds that couple the WB HRZS® coating directly to the steel substrate.
Although waterborne zinc coatings have come a long way from the original heat-cure products developed in Australia in the 1930’s to the self-curing versions in the 1960’s, it was not until 1970 that NASA took the product to the next level by increasing the mole ratio of dissolved silica to potassium oxide in the liquid binder from 3.2:1 to 5.3:1. As a result, this made the product cure even faster (dry in 30 minutes at 77°F) and applicable at upwards of 8-12 mils DFT without mudcracking. And this is what the Polyset WB HRZS® technology is based upon, the original NASA-patented formulation.
Why did a previously NASA-patented coatings technology find its way into such a wide range of industry applications?
It’s simple, really. This product prevents corrosion on steel structures anywhere there is atmospheric and/or industrial corrosion. In the 1980s, when the NASA patented product was made available to the commercial markets, it took the corrosion world by storm. It was, and still is, used on bridges, ships, offshore oil platforms, land-based oil platforms, trucks, pipelines, hydro generation facilities - anywhere corrosion exists.
How are the corrosion protection properties of WB HRZS® advanced compared to other coating solutions available on the market?
WB HRZS® has a dual bonding process when applied to steel. When first applied to properly prepared steel, WB HRZS® makes an initial mechanical bond, which is the same for most all other coatings. However, this is where all other coatings stop bonding. WB HRZS® has a second bonding reaction that is a true covalence chemical bond; WB HRZS® literally becomes part of the parent steel. It should be noted that only a 100% waterborne product can create a true chemical bond. The advantage of the chemical bond is that once cured, WB HRZS® will never uncut or blister. Mechanical bonded coatings, when damaged, allow moisture to migrate under the coating causing blisters to form. As the blisters bop off, the steel corrodes and undercuts beneath the coating, causing the coating system to fail.
Additionally, when WB HRZS® is exposed to the elements that cause corrosion cells, it reacts with the elements and creates a zinc-containing ceramic barrier at its surface, which seals off the coating, making it inert and impermeable to moisture. Therefore, it will not lose millage (thickness). If WB HRZS® is ever damaged, even down to the steel substrate, the exposed zinc metal will react and seal the damaged area to protect the coating film and the steel from corrosion.
Where is it typically used?
As mentioned above, WB HRZS® is used anywhere corrosion exists. For atmospheric settings, a single coat of WB HRZS® is applied at 6-8 mils thickness – that’s all that is necessary. For industrial, high-corrosive applications, we would evaluate the potential chemicals that it would be exposed to and determine if anything is present that could be detrimental to the longevity or performance of WB HRZS®. If a setting was determined to expose WB HRZS® to very low (acidic) pH of 4 or less or to high (caustic) pH of 10 or more, we would inform the potential customer about these findings and make our best recommendation for an additional topcoat.
How easy is it to prepare and apply?
WB HRZS® is very easy to prepare and apply to properly-prepared steel substrates. There are two components: Part A, which is the liquid silicate, and Part B, which is the zinc powder. Using a mechanical mixer, we add Part B to Part A, mixing as the zinc powder is poured into the liquid silicate. Once mixed, which takes about 3 minutes, the WB HRZS® is poured into a pressure tank that has an internal agitator that keeps the zinc in suspension. Air is used to pressurize the tank and hoses are attached to the tank, one for air atomization and one for material inside the pressure tank; both lines go to a spray gun. The material is now ready to spray onto the steel structures. For small touch up areas, WB HRZS® can be applied with a nylon bristled brush.
Protect your steel structures against corrosion
How does WB HRZS® save your customers time and money?
Since WB HRZS® is a Single Coat System, it saves customers a lot of time compared to multiple-coat systems that consist of a primer, mid-coat, and topcoat. If using a three-coat system, the applicator needs to take into consideration the time it takes to mix and apply the multiple coats, as well as the dwell time it takes each coat to dry before the next coat can be applied.
In terms of cost savings, a single coat system doesn’t require the administrative costs for procuring multiple products, material handling, warehousing, shipping costs, and other miscellaneous expenses.
Another cost factor to consider is the clean-up and VOC reporting. WB HRZS® is 100% Waterborne, so there are no additional costs for cleaners or thinners. You only need water for cleaning the equipment and WB HRZS® doesn’t require thinning. Coating applicators may have VOC limits they must report each month, and if they exceed their VOC limit there are fines and additional costs to dispose of HAZMAT materials.
How does the costing system react to damages sustained while in use?
If WB HRZS® is damaged, it will react with the environment where it is applied and seal the damaged area. This prevents any migration or creation of corrosion because it is chemically bonded to the structure and will never undercut or blister. This reaction is kind of an oxymoron since ions in our atmosphere that start and typically cause corrosion cells to form are actually absorbed and compounded into the WB HRZS®. As this reaction takes place, the WB HRZS® becomes harder, which provides great abrasion resistance. Additionally, the ceramic barrier is formed to whatever depth is needed to protect the steel substrate and to protect the WB HRZS® from sacrificing and destroying itself.
Are there any case studies you are particularly proud of?
Yes, in preparation of the 100th Anniversary Celebration of the Statue of Liberty (held in 1986), an enormous refurbishment project was conducted on the sculpture. During the structural analysis and recommendations, it was determined to reinforce the interior steel frame that supports the outer copper figure and to use WB HRZS® Single Coat System, marketed at the time as IC531, to protect the steel from corrosion. Today, WB HRZS® is still protecting the Statue of Liberty from corrosion!
Additionally, in 1996, WB HRZS® Single Coat System was inducted into NASA’s Hall of Fame for Corrosion Prevention Coatings. At the time, our WB HRZS® technology was marketed as IC531.
On a personal note, I am very proud to have been involved directly with using Polyset’s WB HRZS® Single Coat system on every US Navy and US Army causeway watercraft systems built from 1989 – 2008. This was prior to my employment with Polyset, which started in 2010 as the Product Manager for Protective Coatings.
What life span can users expect from WB HRZS® coating system?
In even the harshest corrosive atmospheric environments the honest answer is, we do not know.
- In the late 1960s, NASA applied product that is still in place. Note that NASA, Kennedy Space Center has the highest corrosion rate per day in the USA.
- More than 30 years ago, we partnered with a major power company (located in Florida) that has structures in place protected by WB HRZS®.
- In 1986, US Navy causeways were coated with WB HRZS® and are still in great shape.
- More recently, we have Hydro Electric Dam sites where WB HRZS® was applied to the flood control gates, and after 7 years exposure to the atmosphere, as well as in immersion, the gates still look exactly the same as the day they were installed.
How do organic coatings compare in terms of corrosion resistance, toughness and application?
The disadvantages of organic coatings to Polyset’s inorganic WB HRZS® are:
- The bonding mechanisms. Organic coatings are purely mechanical and will undercut and blister. WB HRZS® is mechanical and chemical. The dual bonding makes a stronger bond which will never undercut or blister.
- Self-healing properties. Organics will not self-heal, WB HRZS® will self-heal.
- Permeability. All organic coatings are moisture permeable to various degrees. WB HRZS® is impermeable to moisture.
- Number of coats. Most organic coatings require multiple coats for toughness and durability. WB HRZS® needs only one coat for toughness and durability.
- UV protection. For UV (fading and chalking) resistance most organic coatings require multiple coats of different technologies; i.e. epoxy midcoat for durability and a UV resistant topcoat for UV protection. WB HRZS® is fully UV resistant even with just one coat.
- VOC content. Most organic coatings have VOC content (there are some exceptions) and most organic coatings require multiple, solvent-based coats. WB HRZS® is 100% Waterborne and contains 0 VOCs.
Are there any other applications in industry where you think WB HRZS® coating system would provide significant value?
Yes, nuclear applications. WB HRZS® Single Coat System is resistant to nuclear radiation. It can also be an excellent, cost-effective alternative for Hot Dipped Galvanizing (HDG) and thermally sprayed metal coatings, such as Thermal Spray Zinc (TSZ) and Thermal Spray Aluminum (TSA), providing equal or greater corrosion protection.
Where can our readers learn more?
Readers can visit our website www.polyset.com under our Protective Coatings section. They may also visit our Global Projects section to review many applications where our product is used in several market sectors.
About Earl W. Ramlow
Earl W. Ramlow is the Product Manager – Protective Coatings Division – at Polyset. With nearly 30 years in the protective coatings industry, specifically in marine (US Navy and US Army Causeway Systems), Earl has worked in various roles from coatings system standardization facilitator to new product development to engineering management.
Disclaimer: The views expressed here are those of the interviewee and do not necessarily represent the views of AZoM.com Limited T/A AZoNetwork the owner and operator of this website. This disclaimer forms part of the Terms and conditions of use of this website.