VCCI Dayori No.71

EMC on the Internet (No.10)

Plating and Catalyst

Nobuhiko Tsunefuka

---

?The most famous statue of Buddha in Nara must be the one in Todaiji of Kegon Sect. It is a huge statue of Buddha (Birushananyorai) of height of 16 meters, width of 12 meters and weight of 112.5 tons. The Emperor Seimu wished for the establishment of peaceful country and ordered the construction of statue in October 743. The Emperor Kenko had held a consecrating ceremony of a newly made Buddhist image in 752. So, it is more than 1250 years old now. Over the long history, the statue has experienced several wars and storms, however, it does show any sign of corrosion yet. It proves the high level of technology of the era. It took total 11 years to complete the construction spending 5 years for molding and assembling the body and 966 of rahotsu, a curled bun of hair, and 6 years for the surface processing and plating. They used gold-plate technique that applies gold amalgam, a mixture of gold and mercury, to the surface of statue and heat up from the inside of the statue. When the statue is heated up, the mercury evaporates and causes mercury poisoning. To avoid it, people used gas masks.

The statue of Buddha in Nara

?In Japanese, “plating” is called “Mekki” and written in Katakana character as many other foreign-language derived words. However, it is pure Japanese word. The way to describe in Kanji was modified for three times. (It changed from”??”, “??” “??” and “??”.) After the second Kanji, Mekkin, the word lost the last sound, “n” and the pronunciation of the word was settled as Mekki. Besides metal, plating is applied to other material. One of such application is electroless plating for plastic mobile phone case and operation bottom that serves as electromagnetic wave shield. In addition, copper plate is used for the lead of MCM case that stores several LSI chips and wiring inside of LSI.

In Japanese expression, the situation that someone got too drank and exposed his/her real personality is called, “his/her plate was peeled”. So, conventional idea about plating must be that it easily comes off. To avoid such result, the surface of plated material should be nicely smoothened and catalytic metal has to be applied as undercoat. Both plating and makeup requires a good facial treatment.

Electroplating lesson by Kazuo Serida
http://www.nc-net.or.jp/kouza/mekki/

Cross Section of Skin

?Berzelius of Sweden who is widely known as a father of chemical notation coined a word, Catalyst, for the material that accelerates chemical reaction, in 1835. It is translated into Japanese word, Shokubai. To follow the regulations about the exhaust gas level, gasoline engine cars and diesel engine cars have an exhaust gas control system that uses oxidizing catalyst and reduction catalyst to reduce CO?, NO?, SO? and particulate matter. Catalyst does not change the form itself but keeps working and controlling reaction. It contributes for the reduction of pollutions.

About the chemical reaction with catalyst
http://www.kek.jp/newskek/2003/sepoct/RhCO.html

Catalysis Society of Japan
http://www.shokubai.org/

?Many construction sites use panels with photocatalytic titanium oxides coating as a wall to surround the scene. The panel does not require frequent care and cleaning because the contamination with grease and soot is dissolved with rain. In addition, solar energy creates active oxygen with catalyst, causes redox reaction and dissolve odor. Therefore, it is used in air-conditioner and air-cleaner at home and hospitals to reduce the odor caused by ammonia and aldehyde. Since the titanium oxide-coating material dissolves nitrogen oxides and sulfur oxides, it is also used as construction material for building and road to purify the air in the congested traffic area. Another application is a water purifying system for factory because the coating is able to dissolve organic chlorides. In 1967 Akira Fujishima, a professor of Graduate School of The University of Tokyo, found the characteristic of photo-catalysis of titanium oxide that is currently utilized at many places. The original purpose of research of titanium oxide was the mass production of hydrogen. However, it was found that titanium oxide has variety of useful characteristics. For example it dissolves chemical material and it has high water repellency due to high hydrophile property. The application has been studied further and the material has been used in many new products.

Fundamental principle of photocatalysis
http://www.jpo.go.jp/shiryou/s_sonota/hyoujun_gijutsu/hikari_shokubai/01_mokuji.htm

?Carbon and ferrite electromagnetic wave absorber that is familiar in the world of EMC converts the energy of electromagnetic wave to heat and prevents the reflection of electromagnetic wave. Lately, researchers are studying about new absorbers. One of new absorbers is wave absorber that is used outdoors and absorbs noise. The other is ferrite plating that is applied to high-frequency IC chip. As photoctalysis is applied for many purposes, it is expected to see interesting new products with electromagnetic wave absorber that utilizes electromagnetic energy.

Electromagnetic wave absorber for ETC and DSRC
http://www.mitsubishi-cable.co.jp/jihou/pdf/99/12.pdf

Ferrite plating technique by Professor Masaki Abe of Tokyo Institute of Technology
http://www.pe.titech.ac.jp/AbeLab/index-j.html

Nobuhiko Tsunefuka 1943 Born in Tokyo 1968 Graduated form Department of Engineering Science, Osaka University -1984 Worked on developing Information Technology Device at Taga Works, Hitachi, ltd. 1991- Engaged in education on EMC related matters at Hitachi Institute of Technology 1999- Planning Manager,