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22XV International Symposium on Self-Propagating High-Temperature Synthesis
YESTERDAY, TODAY AND TOMORROW CHALLENGES FOR SHS Y. Miyamoto
Joining and Welding Research Institute, Osaka University Mihogaok 1-1, Ibaraki City, Osaka 567-0047, Japan e-mail: [email protected]
DOI: 10.24411/9999-0014A-2019-10099
The SHS was born in 1967 on the earth of Russia from the great father Prof. A.G. Merzhanov and mother Prof. I.P. Borovinskaya. It was carefully grown mainly in a secret research town, Chernogorovka in the age of Soviet because of the great potential not only for science, but for industrial applications. The key issues are the very rapid and energy saving process releasing high thermal energy with high temperatures, and the productivity of numerous materials. Human history often gives hard lessons like the collapse of Soviet Union in 1991. For SHS, however it might open the more challenging future. The research and development power of SHS was released to the world through America, Poland, and Japan since early 1980's, then widely propagated to Korea, China, Europe, and other countries. The 1967 ~1970's may be called as the cradle age of SHS.
While, the 1980's ~1990's can be called as the rapidly growing and challenging age of SHS. This miracle and impressive SHS attracted attention from many ambitious scientists, engineers and entrepreneurs of the world. Various challenging approaches and analytic studies were promoted to understand and apply SHS. American researchers studied on the powder synthesis and the consolidation of advanced ceramics. In Poland, Prof. R. Pampuch and Prof. J. Lis succeeded in the combustion synthesis of unique ductile ceramics of Ti3SiC2 that has much contributed to the current active R&D on MAX phases. In Japan, we succeeded in fabrication of high temperature dense ceramics of TiB2, TiC, and SiC by pressurized SHS in 1984.
Prof. O. Odawara invented a centrifugal thermite technique and formed alumina lining steel pipes in a period of seconds in 1983, of which technique was applied to practical uses in China. Various pressurizing techniques to SHS were developed not only for fabrication of dense materials or composite items, but for welding and lining metals, ceramics and intermetallics in Russia and in other countries.
The development of fine nitride ceramics was a world hot topic aiming to apply to ceramic engine and turbine parts, heat and wear resistant parts, electronic substrates and others in the growing age of SHS. Prof. Borovinskaya and our groups studied intensively the nitriding combustion synthesis of Si3N4, Sialon, AlN, BN, TiN, NbN and others. The conversion of the desert sand of SiO2 to the unique high temperature ceramic of Si2№O was our another challenge. Today, the commercial production of Si3N4, AlN and other nitride powders by the SHS is growing in China.
In 1984, FGM (Functionally Graded Material) was proposed and developed in Japan. The FGM is the new tailored composite of different components such as a high temperature ceramic and a tough metal which are integrated with the graded interface relaxing the thermal stress. We demonstrated TiC/Ni and TiB2/Ni FGMs by developing the SHS/HIP process. In order to realize the further potentiality of SHS, we challenged to develop the 3D-SHS printing and demonstrated some simple objects of NiAl intermetallic compounds in 2001. This unique 3D object can be formed by ejecting tiny molten Al droplets to the moving Ni powder bed on an X-Y-Z stage in the inert atmosphere under the CAD/CAM control.
The first international symposium on SHS was successfully organized in San Francisco, 1988 by Dr. J.B. Holt and Prof. Z.A. Munir. In 1992, the periodic issue of the international journal
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Y.Miyamoto
iSHS 2019
Moscow, Russia
on SHS has started. A Japanese text book entitled "Chemistry of Combustion Synthesis" was published in this year. Because no such a text book existed anywhere, it was translated into Russian and published.
The SHS has various advantages except a problem of difficult control. Unfortunately, SHS researchers cannot figure out yet the real answer to this difficulty.
Today, we are successfully producing fine and pure AlN powders by the controlled self-purification process of SHS. The AlN powders and fillers can be used to excellent heatsink substrates and sheet for electronic devices and LEDs, plasma and corrosion resistant parts of semiconductor manufacturing equipment, and phosphor materials.
In the 21st century, the energy and environmental issues will be more serious, while the space age should be full opened. The SHS is essentially energy saving, energy producing, self-controllable and environment-friendly process. In order to take advantage of SHS in the 21st century, we must further challenge to get more powerful abilities of precise analyzing and comprehensive understanding the very complex and delicate SHS using a modern tool of AI (Artificial Intelligence), and of fine and sophisticated control techniques for the stable and uniform combustion process. To stay on moon and Mars, it is necessary to construct space buildings, structures, and produce thermal energy using limited resources in vacuum and low gravity environment. The combination of SHS with AI and IoT (Internet of Things) may bring the new generation SHS which can act as a universal material and combustion science and technology in the space age. This is my dreaming of SHS on the earth.
Y.Miyamoto
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