Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Coffee, Tea or Polishing Slurry?

27.04.2004


The same stuff that stains your coffee mug could reduce pollution in the computer hard-drive industry, while saving drive makers millions of dollars in manufacturing costs.


Two UA engineering grads and a UA engineering professor have developed an environmentally friendly polishing/lapping slurry that could save millions for computer hard-drive manufacturers. They are (from left) Materials Science and Engineering (MSE) alum Don Zipperian (Pace Technologies), MSE alum John Lombardi (Ventana Research Corp.) and MSE Professor Srini Raghavan. (Photo by Erica von Koerber, Evon Photography)


This separatory funnel contains an additive for polishing/lapping slurries that was developed by Ventana Research Corp. The additive is derived from green tea. (Photo by Erica von Koerber, Evon Photography)



The compound is derived from the tannin phytochemicals commonly found in plants. Green tea has a lot of them.

John Lombardi, president of Tucson-based Ventana Research Corp. combined phytochemicals from green-tea extract, synthetic proteins and an abrasive to produce a lapping slurry that is three to four times faster at polishing magneto-resistive heads than the ones currently in use. An added bonus — one that could save millions of dollars for hard-drive manufacturers — is that it’s also environmentally friendly, unlike many of the solvent-based slurries now used.


Lombardi, who earned his master’s (1994) and Ph.D. (1996) degrees from UA in Materials Science and Engineering (MSE), admitted that green tea isn’t intuitively obvious as a key ingredient in lapping slurries. He made the link after looking at the compounds that allow barnacles to cling tenaciously to ship hulls. These compounds have a chemical structure that is similar to that found in tannin phytochemicals. "This led me to start looking at various tannin phytochemical compounds as a general class of chemicals," he said.

"There are probably thousands of these chemicals in nature," Lombardi added. "We’re using green tea because it has a high percentage of phytochemicals."

UA MSE Professor Srini Raghavan has been working with Lombardi to test the green-tea compound as a slurry additive and is conducting basic science experiments to find out why it works so well.

A third team member, Don Zipperian, of Pace Technologies, is providing the industry perspective by determining precisely which slurry attributes are most valuable to hard-drive manufacturers. He also will be heavily involved in marketing the Ventana slurry. Pace Technologies is a Tucson-based company that sells products for micro-surface finishing.

The ceramic debris particles scrubbed away during hard-drive head polishing are submicron-size (less than a millionth of a meter in diameter) and cling to the surface, making them difficult to remove. Tannin phytochemicals have a strong affinity for these tiny particles, tightly bind to them and give them an electrostatic charge, which causes the particles to be repelled from other particles and the head surface. This makes them float so they can be easily washed away with water.

"The tannin phytochemicals play a dual role by increasing the polishing rate and enhancing the removal of particles produced by the polishing process," Raghavan explained.

Lombardi noted that the computer industry produces more than 161 million hard drives annually, with read-write heads that must have no imperfections larger than 10 angstroms. That’s tiny. The average human hair has a diameter of about 75,000 angstroms.

Polishing with this kind of precision isn’t easy. Zipperian, who earned his Ph.D. from UA MSE in 1987, compared the polishing process to flying a 747 at full throttle a few inches off the ground. Zipperian is chief technical officer for Pace Technologies, whose customers include semiconductor, hard-drive, and fiber-optics manufacturers, as well as companies in the metallographic industry that test materials, including metals, ceramics and plastics.

He said hard-drive manufactures incur significant disposal costs from the industrial solvents currently used for polishing read-write heads.

"As far as we know, all the chemicals we’re using should be biodegradable," Lombardi added. "Most of the chemicals and reactants we use are shipped in foil-lined bags and there are no materials-handling problems involved." Switching to these biodegradable chemicals could save manufacturers millions of dollars in disposal costs.

Ventana Research Corp. formulates specialty compounds, and now is looking at other applications for tannin phytochemicals. Their high affinity for metals and ceramics could lead to applications in mining, cancer treatment, high performance adhesives, specialty coatings, removal of metal contaminants from water, and wastewater treatment.

Lombardi, Raghavan and Zipperian developed the lapping/polishing slurries through a National Science Foundation (NSF) Small Business Innovation Research (SBIR) grant.

Ed Stiles | University of Arizona
Further information:
http://uanews.org/cgi-bin/WebObjects/UANews.woa/wa/SRStoryDetails?ArticleID=9109

More articles from Process Engineering:

nachricht Quick, Precise, but not Cold
17.05.2017 | Fraunhofer-Institut für Lasertechnik ILT

nachricht A laser for divers
03.05.2017 | Laser Zentrum Hannover e.V.

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Collapse of the European ice sheet caused chaos

27.06.2017 | Earth Sciences

NASA sees quick development of Hurricane Dora

27.06.2017 | Earth Sciences

New method to rapidly map the 'social networks' of proteins

27.06.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>