Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Coffee, Tea or Polishing Slurry?


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:

More articles from Process Engineering:

nachricht Applying electron beams to 3-D objects
23.09.2016 | Fraunhofer-Institut für Organische Elektronik, Elektronenstrahl- und Plasmatechnik FEP

nachricht New process for cell transfection in high-throughput screening
21.03.2016 | 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: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

First-time reconstruction of infectious bat influenza viruses

25.10.2016 | Life Sciences

Novel method to benchmark and improve the performance of protein measumeasurement techniques

25.10.2016 | Life Sciences

Amazon rain helps make more rain

25.10.2016 | Life Sciences

More VideoLinks >>>