Ceramic Semi-Conductors?

Dr. Jagdish Narayan, a researcher at North Carolina State University, has developed a new ceramic material that has exciting applications in semi-conductor technology. By adding some strategically selected impurities to their ceramics research, they have created a chip that can hold one bit of data in a space that is 90% smaller than existing technologies. Narayan says,

"Instead of making a chip that stores 20 gigabytes, you have one that can handle one terabyte, or 50 times more data."

This development is extremely exciting. If the research turns out to be scalable and mass-producible, then it could lead to the spread technical ceramics applications outside of areas like ceramic wear components and such.

Surfer Dude Saves Indonesian Town

Here’s a great story that involves surfers, earthquakes, and ceramic water filters. Jon Rose, a Long Beach, CA resident whose father, Jack Rose, has a non-profit called Rain Catcher. The non-profit helps to educate villagers in Africa about rainwater collection and filtration. The son had just launched Waves for Water, which follows a similar idea and applies it to popular surf regions.

Jon Rose had been surfing in Indonesia when a massive 7.6-on-the-Richter Scale earthquake struck on 30 September. Luckily, the surfer had stowed some ceramic clay water filters in his surf bag. Through immediate, attentive effort, Mr. Rose was able to provide filtration for the region, which has a population of over 750,000 residents. The earthquake had wiped out their previous water supply.

Maybe we should change the filter more frequently?

At our company, we drink tap water. Besides saving money, drinking tap money has been shown time and again to be as clean--if not cleaner--than bottled water. However, we noticed that our water was starting to taste a little bit off, so we examined the water filter. A ha! Take a look at this.
That cylinder on the top is the one that's been in (over)use, the one on the bottom is the replacement filter. The filters are made of ceramic. Ceramic makes an excellent water filter due to its density and porosity, both of which can be easily controlled. This particular filter features Sterasyl ceramic, which has a highly consistent and controlled pore structure, which can remove a wide range of water borne contaminants. They don’t restrict the flow of the water, and they make the water taste great, which means like nothing at all!

A New Report on the Market Outlook for Silicon Carbide

Silicon carbide (SiC), which is also known as carborundum, is a compound of silicon and carbon. It occurs in nature as the extremely rare mineral moissanite. It’s been used as an abrasive since 1893, and nowadays it is used in applications as various as car brakes and ceramic bulletproof vests to light-emitting diodes and radio detectors. SiC is also widely used in high-temperature semiconductor electronics, due to its amazing temperature-resistant properties.

There was a recent report from tech consultant Yole Développement outlining a curious absence of silicon carbide-based transistors, which was reporter in Semiconductor International. According to the report, the total market for SiC devices is $2.6 billion, more than 20% of the entire silicon-based power business in 2008. However, this share is expected to grow as various factors constraining SiC’s market penetration are overcome.

One factor slowing down SiC market penetration is its high cost. Low-voltage applications comprise the vast majority of SiC-based devices, which tend to have low margins. Medium-voltage (1.2 to 1.7 kV) applications are expected to increase over the next two to three years. High-voltage applications are expected to appear slowly beginning in 2013 or 2014 as technological improvements and cost reductions make SiC applications viable.

Total SiC substrate merchant market reached approximately $48 million in 2008, and it is expected to exceed $300 million during the decade. However, its relative share is looking like it will decrease. Currently, Chinese production companies are driving growth in the SiC transistor market. On the high end of projections, a yearly $800 million market can be expected for the SiC substrate transistor sector.

Zirconium: Not Just For Rings and Things

If you’ve ever watched a shop at home television channel or been in the market for inexpensive jewelry, then you’re probably familiar with cubic zirconia, the synthetic alternative to diamonds. According to Wikipedia, cubic zirconia has been the most “economically important competitor for diamonds since 1976.” More generally, though, zirconium is a chemical element (Zr) that is found in nature within the earth’s crust and sea water. Its applications are much wider-ranging than jewelry.

Zirconium’s global usage shows that it is predominantly used within the field of technical ceramics. For instance, 54% of China’s zirconium consumption goes towards ceramics. Zirconium is extremely hard, stable, and dense. It is overwhelmingly strong. Its fine grain size makes it perfect for creating sharp blades. Ceramic knives are one of the latest crazes in kitchenwares, for instance. In addition to sharpness, zirconium can be used to create porous ceramic filters and diffusers for washing and spraying functions. Its durability, density, and corrosion resistance allows it to be used in applications that require dealing with acids.

I stumbled across this page, which gives a lengthy overview of zirconium, from its global availability and application to end users and producers.

Zircon consumption, like that of most other commodities, has been hit by the global economic slowdown. However, supply (both existing and potential), too, appears to have been impacted equally, if not more, severely. Not only have a number of suppliers in both Africa and Australia (for example, Australian Zircon NL (Bloomberg Ticker—AZC:AU)) been facing financial challenges, with consequent decreases in production, but other producing countries have also been facing limitations on production. Indonesia, in particular, saw zircon production fall more than 40% in 2008 from the level in 2007.

In addition, Refractron has an excellent page about a special kind of zirconium, Yttria Tetragonal Zirconia Polycrystal (Y-TZP).

Y-TZP has a material density of greater than 6.0 g/cc, a maximum operating temperature of 2000 C. This material has the highest flexural strength of the zirconia materials particularly when processed using a HIP (Hot Isostat Press). Values are 900 MPa and 1400 MPa (HIP'd). The hardness is 13-13.5 GPa, Fracture Toughness is 8.0 MPa-m1/2 and Thermal expansion (C.T.E.) is 10.2 x E6/ degree C).

So the next time you’re up late and watching QVC shilling cubic zirconium rings, remember that what you’re actually seeing is a product related to technical ceramics.

A Neat Application of Porous Ceramics

Has your space ever been invaded by dust mites, mold, or moisture damage? Well, a Japanese company has created a product called the dehumEGGifier, which utilizes porous ceramics technology to reduce ambient humidity without the intrusion of a noisy, bulky dehumidifier.

The dehumEGGifier, as you can see above, is a rather small, egg-shaped device crafted out of a porous ceramic material that houses silica gel beads. As the silica gel beads absorb moisture through the porous shell, the blue base turns to pink. Once the base is pink, you are to micorwave the egg for about ten minutes, which will desiccate the beads readying the dehumEGGifier ready for re-use.

The dehumEGGifier seems to take advantage of a specific property of ceramics: Namely, that porous ceramics are generally made by fusing metal oxide grains using a porcelain bond, which reates a strong, uniformly porous and homogeneous structure. The resulting material is naturally hydrophilic (that is, having a natural tendency to mix with water), which results in an impressively even transmission of liquid. Porous ceramics--besides having applications in quirky Japanese consumer products--can be used for applications such as spraying, oven firing, and ultrasonic cleaning. For some more information about porous ceramics, check out this page on Refractron's website.

Dr. Harry L. Tuller, MIT professor, to give lecture at Alfred University

Tuller, who is a professor of ceramics and electronic materials in the Department of Materials Science and Engineering, and head of the Crystal Physics and Electroceramics Laboratory (what an elegant title!) at the MIT, will give a talk entitled “Electroceramics: Technology for the Future." His talk is scheduled for 11:20am on 22 October.

According to Alfred University, Professor Tuller's talk will center on,

what makes electroceramics particularly attractive and/or essential for insuring rapid progress in all of these areas, focusing on their high figures of merit in information and energy transduction and in their thermal, mechanical, and chemical stability. Examples are provided to illustrate where electroceramics are likely to play a particularly strategic role in the future.

It looks like an extremely interesting lecture. I hope to see you all there!