Researchers use nanotechnology to enhance corrosion protection

 

Nanotechnology is one of the world's most rapidly growing fields across a wide swath of industries from pharmaceuticals to engineering. Nanotechnology refers to the many disciplines in science and technology that benefit from controlling matter on the atomic and molecular level, using the nanoscale for measurement. To place the size in perspective, 25.4 million nanometers are in one inch. 

Within the material sciences, corrosion protection is an exciting area for the use and development of nanotechnology. Protecting materials from corrosion is a big challenge in the engineering and science world. 

Today, one of the most vexing problems facing the corrosion resistance community are rising prices of raw materials such as zinc, lead, chromium and molybdenum. Another issue is the marketplace wants environmentally friendly, "green" corrosion coatings.

Last month, scientists from the Institute for Color Science and Technology (ICST) in Iran discussed the results from their research involving nanotechnology. They studied ways to improve the quality of corrosion protection offered by coatings enhanced with modified nanoparticles. 

The research explored the effect of impure zinc oxide nanoparticles doped with manganese and cobalt to tame the corrosion problems in coatings and improve the quality of coatings.

According to Dr. Bahram Ramezanzadeh, a member of the scientific board of ICST, the results of this research will play a big part in solving the corrosion problems in industries including:

• oil reservoirs
• oil and gas pipelines
• marine installations
• power plants

"In this research, we tried to create corrosion-prevention behavior in addition to blocking properties by doping zinc oxide nanoparticles with cobalt and manganese," Ramezanzadeh said. "In addition, their surface was modified with silane agent to obtain appropriate distribution of nanoparticles in the matrix of the epoxy coating." 

The use of zinc oxide nanoparticles treated with cobalt and manganese improves the anti-corrosive coating by adding two ways of enhancing corrosion prohibition properties and blocking corrosion. Using the enhanced zinc oxide paste on metal increases the lifetime of metal construction in hostile environments that lead to corrosion, cuts the use of metal and increases the efficiency of the devices coated. 

Over the past 20 years, researchers have discovered new insights into how nanotechnology works and how its scalability works for not only metals, but also for concrete, stucco and scores of other materials that benefit from the corrosive protection added by nanotechnology. Time will tell what new methods will be discovered in this rapidly growing field. 

Leopad Group a leading provider of corrosion protection services ranges from the scope of blasting and painting, insulation, thermal spray application, passive fire protection, refractory and other services such as scaffolding, cable tray systems and cathode protection. 

We are a Malaysian company with close to 3000 staff and over 10 offices and fabrication yards throughout the country. Leopad Group is dedicated to being the market leader for corrosion protection and provide the highest standards in the industry with the convenience of providing multi-disciplinary services through a single point of contact.

For further enquiries on our services, please contact our Business Development Department at +603-22600200 , website www.leopad.com or email at [Company E-mail]

Source: Alan Kelsky  http://exclusive.multibriefs.com/content/researchers-use-nanotechnology-to-enhance-corrosion-protection

The Use of Nanotechnology in anti corrosion coatings

Due to the massive economic impact of corrosion degradation on metallic structures, the area of active protective coatings has been developed very fast in the past few years. The goal is to significantly reduce the maintenance costs in many industrial applications by applying active sensing coatings. The indication of corrosion activity by these coatings will allow optimization of the maintenance operations avoiding excessive unnecessary preventive operations in the cases when coating is still able to protect the metallic structures. 

Today we look at a novel sensing active coating on the basis of nanocapsules containing pH-indicating agent. The main idea of this work by a research team from the University of Aveiro in Portugal, is to create a novel active protective coating which is able to indicate when corrosion processes start under the coatings or in different defects.

The nanoreactors being introduced in the coating change their color in the zones where corrosion processes start. An important feature of these nanoreactors is that the indicating molecules are not released from the mesoporous nanocarriers, thereby preventing spontaneous leaching and ensuring long service time.

Scheme of pH sensing response from coating. (© IOP Publishing)

The team, led by Mikhail Zheludkevich, a senior researcher at the university's Department of Materials and Ceramics Engineering, CICECO, published their findings in the September 17, 2013 online edition of Nanotechnology ("Nanocontainer-based corrosion sensing coating").

"The corrosion sensing can be considered as independent functionality of a protective coating or can also be considered as an important additional functionality which can complement the self-healing coatings," Zheludkevich tells Nanowerk. "For example, the new coating developed by our group in collaboration with several European partners from academic and industrial sectors is counting on the multi-level self-healing effect based on 'smart' nanocontainers. The main idea is that several mechanisms of self-healing can be integrated in the same coating providing effective active protection which is proportional to the external impacts such as corrosive attack and mechanical impacts.

In such a coating, the active healing agents responsible for different mechanisms are encapsulated in micro- or nano-containers and then integrated into the polymer coating. Different nanocontainers can introduced to different layers of the coating or can be used in a single layer system.

Pictures of coated substrates doped with Si NC–PhPh and tested during 3 days in 0.5 M NaCl: (a) and (b) coated aluminium alloy with artificial scribe, (c) and (d) coated magnesium alloy without scribe. (© IOP Publishing)

These coatings were developed in the frame of large-scale European project MUST ('Multi-Level Protective Materials for Vehicles by 'Smart' Nanocontainers').

In their work, the team encapsulated phenolphthalein – a colorless crystalline solid often used as an acid-base indicator – in mesoporous silica nanocontainers.

"With the onset of corrosion, pH increases in the local cathodic areas due to the formation of hydroxide ions whilst acidification often occurs at anodic sites as a result of hydrolysis reactions," explains Zheludkevich. "The respective pH variations can be used to detect and locate the active corrosion spots in confined defects of the coatings or under the coatings if pH indicators are incorporated in a polymer protective layer."

The main idea of the team was to provide a color change signal as a result of pH change in the vicinity of a nanocontainer with consecutive diffusion of hydroxide ions into the mesopores reacting with pH indicator within the container.

As Zheludkevich points out, the introduction of corrosion sensing functionality to the self-healing coating is an important step which allows detecting the moment when the coating is not able to heal the defects anymore and an external intervention is needed to avoid an extensive corrosive damage.

One challenging future direction for this research area is the integration of several functionalities into the protective coatings. The objective would be to develop coatings which not only integrate several self-healing mechanisms at the same time but also provide additional self-monitoring tasks with optional antibacterial or antifouling functionalities.

By Michael Berger. Copyright © Nanowerk