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High-Tech Materials Alert reports developments in advanced materials,
including new processes to create and manufacture them. Each issue keeps you
informed of important new developments as they emerge from the laboratory
towards commercialization, including advances in electronics and photonic
materials, biomaterials, composites, ceramics, high-performance metals and
alloys, novel polymers, diamond-like materials, and intermetallics. Our analysts
go directly to the primary researchers themselves to find out what is in
development and what is likely to have a significant commercial impact.
Each month, a special Market Forecast section thoroughly analyzes an
individual advanced material or materials process. In addition to an expert
forecast of growth rates, market demand, and market size, this section examines
key factors such as supply and demand, obstacles to commercialization, existing
and pending applications, and principle alternatives. High-Tech Materials Alert
also includes a monthly Patent Review highlighting those patents with high
commercial significance. With research occurring across a wide range of
industries, High-Tech Materials Alert is the most efficient way to stay abreast
of significant advances in materials and materials processes regardless of where
they may originate.
Sample Briefing
CHEAPER CERAMIC MICRORODS FOR PIEZOCOMPOSITES BY HIP
It is now possible to make lead zirconate titanate (PZT) ceramic microrods for
I-III piezoceramic devices by hot isostatic pressing (HIP) with silicon molds.
This novel technology, referred to as lost Si mold process, is a marriage of
silicon micromachining and ceramic sintering techniques. The result is
piezoceramic microrods with high aspect ratios that are useful for making
high-resolution micro-ultrasonic transducers.
The process starts by making a Si mold. This is done by making deep holes in
designed shapes and sizes on a Si substrate using reactive ion etching. Then a
PZT slurry is cast into the mold, and the PZT is subsequently sintered by HIP.
Finally, the microrod array is released by selectively etching away the mold
with XeF2 gas. This is in contrast to conventional lost plastic mold techniques
that use X-ray synchrotron radiation, which requires large and expensive
equipment. In addition, microrods made traditionally have unavoidable structure
deformation when feature sizes are smaller than 20 micrometers because the mold
must be removed prior to sintering.
The advanced lost Si mold process is the result of a team effort from three
major materials processing groups at Tohoku University, Sendai, Japan. The
groups are the Venture Business Laboratory, which headed the project, the
Materials Processing department, which contributed Silicon micromachining
expertise, and the Materials Processing and New Industry Creation Hatchery
Center, which offered its HIP expertise and experience. Together, they figured
out how to drive PZT slurry into holes 10 micrometers in diameter and over 100
micrometers deep. This resulted in high-density microrods as fine as 7
micrometers square in diameter and 90 micrometers in height, with an aspect
ratio higher than 15.
* The technology can be altered to make complex fine structures other than
microrods, and at relatively low costs. PZT microrods can be used to construct
high-resolution micro-ultrasonic transducers for ultrasonic imaging. Other
applications include ultrasonic microscopes, piezoelectric actuators, and ink
jets.
* The technology was funded in part by Japan's Society for the Promotion of
Science and the Ministry of Science. It is patented by Olympus Optical Co.
Ltd., and is currently under commercial exploration.
* Shinan Wang, one of the principle developers, has left Tohoku University to
work at Toyota labs and can be reached there. His colleagues at Tohoku
University are continuing PZT-related work.
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