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 A water treatment breakthrough, inspired by a sea creature
27.11.2018 | Yale University

nachricht Research project AutoAdd: Paving the way for additive manufacturing for the automotive industry
22.11.2018 | Fraunhofer-Institut für Lasertechnik ILT

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: An energy-efficient way to stay warm: Sew high-tech heating patches to your clothes

Personal patches could reduce energy waste in buildings, Rutgers-led study says

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

Magic number colloidal clusters

13.12.2018 | Life Sciences

UNLV study unlocks clues to how planets form

13.12.2018 | Physics and Astronomy

Live from the ocean research vessel Atlantis

13.12.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>