J. Inst. Electrostat. Jpn.

, 31, 5 (2007) 205 206

ᶧਛࠍᚑ㐳ߔࠆ࠺ࡦ࠼࡜ࠗ࠻ߩ᜼േߦ㑐ߔࠆᬌ⸛᳓ᚭㇱ ৻ ቁ㧖,1㧘ᓟ ⮮ ⌀ ሶ*㧘ศ ᧛᣹㧖㧔2007 ᐕ 3 ᦬ 23 ᣣฃઃ㧘2007 ᐕ 7 ᦬ 20 ᣣฃℂ㧕Study on the Behavior of Dendrites Grown in LiquidKazutaka MITOBE㧖,1, Mako GOTO* and Noboru YOSHIMURA*(Received March 23, 2007; Accepted July 20, 2007)

The electric field of the circuits is getting higher from year to year because of the trend of reductions in size and weight. It isdifficult to keep the reliability of electric circuits under a higher electric field for a long term because an ion migration that isone of the reasons of insulation deterioration develops in the circuits. In this study, we measured the three-dimensional
configuration of dendrites in ion-exchanged water. It is clear from this study that a few dendrites grow up in an upright stanceto the PWB surface.
1.

Cover glass 㽳⢛᥊ㄭᐕ㧘㔚ሶ࿁〝ߩ㓸Ⓧൻ࡮ዊဳൻߦ઻޿㧘ࡊ࡝ࡦ࠻㈩✢᧼㧔PWB㧕ߩ⛘✼〒㔌ߪ⍴ߊߥࠅ㧘ࠗࠝࡦࡑࠗࠣ࡟࡯࡚ࠪࡦ
㧔IM㧕ߦࠃࠆࡊ࡝ࡦ࠻㈩✢㑆ߩ⛘✼ା㗬ᕈߩૐਅ߇໧㗴ߣߥߞߡ޿ࠆ㧚IM ߩടㅦ⹜㛎ᴺߩ৻ߟߢ޽ࠆ WDT㧔water-drop㽲

test㧕ᴺߢߪ㧘࠺ࡦ࠼࡜ࠗ࠻(dendrite)ߪࠞ࠰࡯࠼߆ࠄࠕࡁ࡯࠼
䋭ᣇะ߳ၮ᧼⴫㕙ߦᴪߞߡᚑ㐳ߔࠆߣ⠨߃ࠄࠇߡ޿ࠆ߇㧘ᶧਛߢߩ࠺ࡦ࠼࡜ࠗ࠻ߩ 3 ᰴర⊛ߥㅴዷߩ᭽ሶߪචಽߦ⺞ߴࠄࠇ

Clear case
Deionized water+DC10V1)

20k㱅Vߡ޿ߥ޿ 㧚ߘߎߢ㧘ᧄ⎇ⓥߢߪ㧘WDT ᴺࠍᡷ⦟ߒߚታ㛎♽࿑ 1 ታ㛎ⵝ⟎ࠍ᭴▽ߒ㧘ᶧਛࠍᚑ㐳ߔࠆ࠺ࡦ࠼࡜ࠗ࠻ߩ㧟ᰴర⊛ߥ᜼േߩFig.1 Experiment setup of modified WDT.

⸃᣿ࠍ⹜ߺߚ㧚3.
3.1

2.

ታ㛎ᣇᴺታ㛎⚿ᨐ࠺ࡦ࠼࡜ࠗ࠻ߩㅴዷߣ⛘✼ᛶ᛫ߩ⚻ᤨᄌൻ

࿑ 2 ߦᱜ㕙߆ࠄ᠟ᓇߒߚ࠺ࡦ࠼࡜ࠗ࠻ߩㅴዷߩ᭽ሶߩઍ⴫

࿑ 1 ߦ WDT ᴺࠍၮߦ⠨᩺ߒߚታ㛎ߩ᭴ᚑࠍ␜ߔ㧚⹜㛎ߦ⊛ߥ଀ࠍ␜ߔ㧚࿑ 2(a)ߪ⹜㛎㐿ᆎ⋥ᓟ‫ޔ‬ห࿑(b)߆ࠄห࿑(f)ߪ

↪޿ߚ⹜ᢱߪ㔚ᭂ㑆㓒߇ 5mm ߩ㌃㔚ᭂߢ޽ࠆ㧚PWB ⴫㕙ࠍ⹜㛎㐿ᆎ߆ࠄ 34 ಽᓟ㧘40 ಽᓟ㧘44 ಽᓟ㧘50 ಽᓟ㧘70 ಽᓟࠕ࡞ࠦ࡯࡞ᵞᵺ߅ࠃ߮⚐᳓ᵞᵺߒߚᓟ㧘PWB ࠍု⋥ߦ┙ߡߩ᭽ሶࠍ␜ߔ㧚࿑ 3 ߦ⛘✼ᛶ᛫୯ߩ⚻ᤨᄌൻࠍ␜ߔ㧚࠺ࡦ࠼ߚ⁁ᘒߢታ૕㗼ᓸ㏜(OLYMPUS)ߦ⸳⟎ߒ㧘㔚ᭂ߅ࠃ߮㔚ᭂ㑆࡜ࠗ࠻߇ߥ޿⹜㛎㐿ᆎ⋥ᓟߢߪ㧘⛘✼ᛶ᛫୯ߪ߅ࠃߘ 1.5Mǡߢࠍⷒ߁ࠃ߁ߦㅘ᣿ߥࠤ࡯ࠬࠍขࠅઃߌߚ㧚ࠤ࡯ࠬߦߪ⣕ࠗࠝ޽ߞߚ㧚࿑ 2(b)ߦ␜ߔࠃ߁ߦ࠺ࡦ࠼࡜ࠗ࠻߇㔚ᭂ㑆㓒ߩ⚂ 3/4

ࡦ᳓ࠍ 125ǴL ౉ࠇߡ㧘ࠞࡃ࡯ࠟ࡜ࠬߢ⬄ࠍߒߚ㧚ߘߒߡ㧘߹ߢᚑ㐳ߒߚᤨὐߢ㧘⛘✼ᛶ᛫୯ߩૐਅߩ൨㈩߇ᕆߦߥߞߚ㧚⋥ᵹ㔚࿶ 10V ৻ቯࠍ 70 ಽ㑆ශടߒ㧘20kǡߩ೙㒢ᛶ᛫ߦ⊒↢ห࿑(c)߆ࠄห࿑(e)ߦ␜ߔࠃ߁ߦ㧘ᚑ㐳ߒߚ࠺ࡦ࠼࡜ࠗ࠻߇ࠕ

ߔࠆ㔚࿶ࠍ 10 ⑽㑆㓒ߢ᷹ቯߒ,⛘✼ᛶ᛫୯ࠍ▚಴ߒߚ㧚߹ߚ㧘ࡁ࡯࠼ߦ೔㆐ߔࠆߚ߮㧘⛘✼ᛶ᛫୯ߦㆊᷰ⊛ߥૐਅ߇⷗ࠄࠇ

ᶧਛࠍᚑ㐳ߔࠆ࠺ࡦ࠼࡜ࠗ࠻ࠍᱜ㕙(࿑ 1 ਛԘᣇะ)߅ࠃ߮஥

ߚ㧚⹜㛎⚳ੌᤨߦߪ㧘ห࿑(f)ߦ␜ߔࠃ߁ߦ㧘࠺ࡦ࠼࡜ࠗ࠻߇

㕙(࿑ 1 ਛԙᣇะ)߆ࠄㆡቱ᠟ᓇߒߚ㧚ᧄ⹜㛎ߦ↪޿ߚ PWB ߪᄥߊỚߊᚑ㐳ߒ㧘ᢙࠞᚲߢࠕࡁ࡯࠼ߦ೔㆐ߒߡ޿ࠆߎߣ߇ࠊ

6 ᨎߢ޽ࠆ㧚߆ࠆ㧚⹜㛎⚳ੌᤨߩ⛘✼ᛶ᛫୯ߪ⚂ 3kǡߢ޽ߞߚ㧚ࠠ࡯ࡢ࡯࠼㧦ࠗࠝࡦࡑࠗࠣ࡟࡯࡚ࠪࡦ㧘࠺ࡦ࠼࡜ࠗ࠻㧘WDT* ⑺↰ᄢቇᎿቇ⾗Ḯቇㇱ㧔010-8502 ⑺↰Ꮢᚻᒻቇ࿦↸ 1-1㧕Engineering and Resource Science,Akita University,1-1 Tegata
Gakuenmachi,Akita 010-8502,Japan1
mitobe@ipc.akita-u.ac.jp

3.2࠺ࡦ࠼࡜ࠗ࠻ߩ஥㕙࿑

࿑ 4 ߦ஥㕙߆ࠄ᠟ᓇߒߚ࠺ࡦ࠼࡜ࠗ࠻ߩㅴዷߩ᭽ሶࠍ␜ߔ㧚࿑ 4(a)ߪ⹜㛎㐿ᆎ⋥ᓟߢ޽ࠆ㧚ห࿑(b)߆ࠄห࿑(e)ߪ⹜㛎㐿ᆎ

206 (32)315㪈㪅㪇㪇㪜㪂㪇㪎ࠗ࠻ᚑ㐳ߩࡕ࠺࡞࿑ߢ޽ࠆ㧚એਅߢߪਣශߩਛߩ࠺ࡦ࠼࡜ࠗ࠻ߦ⌕⋡ߒߡ⺑᣿ߔࠆ㧚࿑ 4(b)ߢߪ㧘࠺ࡦ࠼࡜ࠗ࠻߇ PWBߦኻߒߡ⋥┙ߒߚ⁁ᘒߢᶧਛࠍ᮸ᧁߩࠃ߁ߦᚑ㐳ߒߡ޿ࠆ᭽ሶ߇⏕⹺ߢ߈ࠆ㧚ߎߩߣ߈ߩ࠺ࡦ࠼࡜ࠗ࠻ߩ㜞ߐߪ⚂ 800㪩㪼㫊㫀㫊㫋㪸㫅㪺㪼 㪲㱅㪴

߆ࠄ 44 ಽᓟ㧘48 ಽᓟ㧘50 ಽᓟ㧘51 ಽᓟߩ᭽ሶߢ޽ࠅ㧘㤥ߊ⷗߃ࠆㇱಽ߇࠺ࡦ࠼࡜ࠗ࠻ߢ޽ࠆ㧚߹ߚ㧘ห࿑(f)ߪ࠺ࡦ࠼࡜

2007㪈㪅㪇㪇㪜㪂㪇㪍㪈㪅㪇㪇㪜㪂㪇㪌㪈㪅㪇㪇㪜㪂㪇㪋㪈㪅㪇㪇㪜㪂㪇㪊㪇Ǵm ߢ޽ࠆ㧚߹ߚ‫߇࠻ࠗ࡜࠼ࡦ࠺ޔ‬ᐙߩㇱಽ(࠻࡜ࡦࠢߣ๭߱)㪈㪇㪉㪇㪊㪇㪋㪇㪌㪇㪍㪇㪎㪇㪫㫀㫄㪼 㪲㫄㫀㫅㪴ߣᨑߩㇱಽ(ࡉ࡜ࡦ࠴ߣ๭߱)ߦࠊ߆ࠇߡ޿ࠆߎߣ߇ࠊ߆ࠆ㧚࿑ 3 ⛘✼ᛶ᛫୯ߩ⚻ᤨᄌൻ࿑ 4(c)ߪห࿑(b)߆ࠄ 4 ಽᓟߩ᭽ሶߢ޽ࠆ߇㧘࠻࡜ࡦࠢߣࡉ࡜

Fig.3 Changes in resistance during WDT.

ࡦ࠴߇ᄥߊ㐳ߊᚑ㐳ߒߡ޿ࠆߎߣ߇ࠊ߆ࠆ㧚߹ߚ㧘࠻࡜ࡦࠢcathodeanode߇ࠕࡁ࡯࠼஥ߦᒁ߈ነߖࠄࠇߡ޿ࠆ᭽ሶࠍ⏕⹺ߢ߈ࠆ㧚࿑4(d)ߪห࿑(c)߆ࠄ 2 ಽᓟߩ᭽ሶߢ޽ࠅ㧘࠻࡜ࡦࠢ߅ࠃ߮ࡉ࡜

PWB5mmࡦ࠴߇ߐࠄߦᄥߊ㐳ߊᚑ㐳ߒ㧘ࠕࡁ࡯࠼஥ߦિ߮ߡ޿ࠆ᭽ሶ
߇⏕⹺ߢ߈ࠆ㧚࿑ 4(e)ߪห࿑(d)߆ࠄ㧝ಽᓟߩ᭽ሶߢ㧘࠻࡜ࡦ(a) 0 minࠢ߇ୟࠇߡ PWB ߦઃ⌕ߒߚߩߦኻߒ㧘ࡉ࡜ࡦ࠴ߪᶧਛߢ⋥┙ߒߚ⁁ᘒࠍ⛽ᜬߒߡ޿ࠆ᭽ሶࠍ⏕⹺ߢ߈ࠆ㧚࿑ 4(f)ߪᧄႎ

800㱘m๔ߩ࠺ࡦ࠼࡜ࠗ࠻ᚑ㐳ߩ․ᓽࠍᮨᑼ⊛ߦ␜ߒߚ߽ߩߢ㧘PWBߦᴪߞߡિ㐳ߒߡ޿ߚ࠺ࡦ࠼࡜ࠗ࠻߇ PWB ࠍ㔌ࠇિ㐳ߔࠆtrunkbranchbranch(b) 44 min

branch᭽ሶࠍ␜ߒߡ޿ࠆ㧚ߥ߅㧘PWB ߦኻߒ⋥┙ߒߚ࠺ࡦ࠼࡜ࠗ
࠻ߪ㧘࿑ 2 ߦ߅޿ߡਣශߩ࠺ࡦ࠼࡜ࠗ࠻ߩ⦡߇Ớ޿ㇱಽߦ⋧ᒰߔࠆߣ⠨߃ߡ޿ࠆ㧚

trunk
4.

(c) 48 min߹ߣ߼ᧄႎ๔ߢߪ WDT ᴺࠍᡷ⦟ߒߚታ㛎♽ࠍ᭴▽ߒ㧘᳓Ṣਛ㧔ᶧbranchਛ㧕ࠍᚑ㐳ߔࠆ࠺ࡦ࠼࡜ࠗ࠻ࠍ㧟ᰴర⊛ߦ⺞ߴߚ㧚ߘߩ⚿ᨐ㧘࠺ࡦ࠼࡜ࠗ࠻ߪᔅߕߒ߽ PWB ߦᴪߞߡિ㐳ߔࠆߩߢߪߥߊ㧘ᶧਛࠍ᮸ᧁߩࠃ߁ߦ㧟ᰴర⊛ߦᚑ㐳ߔࠆㆊ⒟߇޽ࠆߎߣࠍ
(d) 50 min᣿ࠄ߆ߦߒߚ㧚trunk

branch(e) 51 mincathodeanode(a) 0 min

cathodeanode cathode(b) 34 min

䋺Dendrite

anode(c) 40 min(f) Model of dendrite growth.
࿑ 4 ஥㕙߆ࠄⷰኤߒߚ࠺ࡦ࠼࡜ࠗ࠻ߣࡕ࠺࡞࿑
Fig.4 Lateral view and model of dendrite.
ᧄ⎇ⓥߩ৻ㇱߪ㔚ሶ࿁〝ၮ⋚ᛛⴚᝄ⥝⽷࿅ߩᐔᚑ 17cathode

anode(d) 44 min

cathodeanode(e) 50 min

cathode(f) 70 min࿑ 2 ᱜ㕙߆ࠄⷰኤߒߚ࠺ࡦ࠼࡜ࠗ࠻
Fig.2 Dendrite observed from the front.

anodeᐕᐲ⺞ᩏ࡮⎇ⓥߦࠃࠅታᣉߐࠇߚ㧚ߎߎߦ⻢ᗧࠍ⴫ߔࠆ㧚ෳ⠨ᢥ₂1) ᓟ⮮⌀ሶ㧘᳓ᚭㇱ৻ቁ㧘ศ᧛᣹㧦㔚᳇ቇળ⺃㔚⛘✼᧚ᢱ⎇ⓥળ⾗ᢱ㧘DEI-06㧔2006㧕17