Industrial waste converted into a coating for aircraft turbines

Industrial waste converted in coating for aircraft turbines

A group of specialists from the Center for Research in Advanced Materials (Cimav), have developed nanostructured coatings capable of withstanding temperatures exceeding 1000 degrees Celsius, which are used in aviation turbine components.

Dr. Ana Maria Arizmendi Morquecho, leader of the project, explained that through the development of coatings the team is looking to solve one of the most common problems in the aviation industry, which is the microstructural degradation of superalloys that integrate turbines due to the high temperatures reached by the devices.

"The components of the blade and nozzle in the hot zone of the turbines, which are made of Nickel-based superalloys, are exposed to temperatures above one thousand degrees Celsius, which causes very strong microstructural degradation of the substrates and impact on the thermal and mechanical properties of the structure by decreasing the energy efficiency of the turbines," explained the researcher.

The project consist in the development of advanced thermal barriers based nanocomposites that would protect the structures from the superalloys some components of the turbine are manufactured with.

For this, the group of Arizmendi Morquecho uses flying ash as a ceramic matrix incorporating various nanoparticles to create new materials developed by researchers.

"We found that taking advantage of the large amount of mullite, which is a chemically and thermally stable compound found in the flying ash, we can use this material as a ceramic matrix, which by the addition of different particles have obtained novel nanocomposites that greatly diminish the thermal conductivity and are used in developing coatings for superalloys," said Arizmendi Morquecho.

Industrial waste converted in coating for aircraft turbines

Besides the application for the aviation industry, this technology seeks to impact in an environmental level with the use of a material that until now was considered polluting industrial waste, such as flying ash, which is mainly obtained from coal plants installed in northern Mexico.

According to Arizmendi Morquecho, after five years of analysing the different materials that could be used as advanced thermal barrier systems, the team is expecting to make the final tests to validate the materials obtained at the laboratory , to continue with the process of scaling up the technology to be transferred to an interested company.

While this technology is considered basic research, its guidance hopes to solve industrial problems.

"This is part of the focus of Cimav at the Park of Research and Technological Innovation located in the Moneterrey, north of Mexico."

"Therefore, we combine a multidisciplinary group of researchers to conduct basic and applied science, as well as having liaisons with industry, academy and research centers globally," explained Morquecho.

Scottish Mullite: Silicate Material That Can Cut Diesel Pollution

Platinum, a rare and expensive metal, is currently used in diesel engines to try to control the amount of pollution released into the air.

Scientists have now developed a new material that is much more effective than platinum in reducing pollution. University of Texas at Dallas scientists have found that oxide mullite could reduce pollution up to 45 percent compared to platinum crystals.

Mullite or porcelainite is a rare silicate mineral of post-clay genesis, They claim that mullite is less expensive to produce compared to platinum crystals.

Mullite was first described in 1924 for an occurrence on the Isle of Mull, Scotland. It occurs as argillaceous inclusions in volcanic rocks in the Isle of Mull and also with emerylike rocks in Sithean Sluaigh, Scotland.

"Many pollution control and renewable-energy applications require precious metals that are limited - there isn't enough platinum to supply the millions and millions of automobiles driven in the world," said Dr Kyeongjae "K J" Cho, professor at the University of Texas.

"Mullite is not only easier to produce than platinum, but also better at reducing pollution in diesel engines."

Diesel engines give higher fuel efficiency compared to gasoline but produce more nitric oxide (NO) and nitrogen dioxide (NO2), which are quite harmful to human health.

Recently, the World Health Organisation (WHO) upgraded the classification of diesel engine exhaust as carcinogenic in humans, putting it in the same category as cigarette smoke and asbestos.

Countries throughout the world have drafted guidelines to reduce diesel air pollution in the next decade.

The new material developed by scientists could be a new cheap and effective way to reduce pollution.

The discovery was made while analysing the chemical components of mullite.

The team used advanced computer modelling techniques to analyse how different forms of the mineral interacted with Oxygen (O) and Nitrous Oxide (NOx).

The study revealed that the oxide mullite reduces pollution up to 45 percent compared to platinum crystals.

"Our goal to move completely away from precious metals and replace them with oxides that can be seen commonly in the environment has been achieved," Dr Cho said.

"We've found new possibilities to create renewable, clean energy technology by designing new functional materials without being limited by the supply of precious metals."