鈣鈦礦粉體合成及電磁波屏蔽複合材料之研究

The Synthesis of Pervoskite Powder and Study of EMI Shielding Material

林南伸(Lin Nan- Shen)

指導教授 ： 段葉方

國立臺北科技大學/工程學院/化學工程研究所/碩士(2007年)

摘要

鑭鍶鈷氧化物鈣鈦礦(ABO3)常應用於氣體感應，鐵電記憶材料高溫燃料電池電極，合成高化學組成之鑭鍶鈷氧化物鈣鈦礦成為學者重要的研究課題。
本研究利用檸檬酸法合成具有巨磁阻效應之鑭鍶鈷氧化物鈣鈦礦粉體La0.7Sr0.3(Mn1-yCoy)O3(y = 0~0.4)藉由金屬錳摻雜取代鈷來探討在B位置原子的取代對於La0.7Sr0.3(Mn1-yCoy)O3的電性影響，並以XRD及四點探偵測其基本性質，實驗結果發現， La0.7Sr0.3CoO3電阻值最低為5.2×10-4 ohm 。
另一實驗則是研究將合成之鑭鍶鈷氧化物鈣鈦礦添加入PU高分子中形成複合材料測試其對電磁波屏蔽效果，利用四點探針電阻率測量儀器，求得導電率，一般而言，電阻率越高代表著對電磁波屏蔽效果越佳 。
而由實驗證實，鈣鈦礦粉體La0.7Sr0.3Co電阻率為最低，可達5.2×10-4ohm，而以La0.7Sr0.3Co為摻雜粉體，在重量百分比為百分之二十五時可達最低表面電阻1.2×102 ohm，此時電磁波屏蔽效果最佳，dB值為13 。

關鍵字

鈣鈦礦 ； 電磁波

並列摘要

Pervoskite structured conductive oxides (ABO3) as La0.7Sr0.3(Mn1-yCoy)O3 attracted a lot of attention in resent years due to a number of application . Particularly, La0.7Sr0.3CoO3
Used in gas sensors , oxygen catalyst and ferroelectric random access memories were studied wildly by scholars.
In this study, we synthesized La0.7Sr0.3(Mn1-yCoy)O3（y=0~0.4）with colossal magnetoresistance by citrate process . By replacing Co3+ with Mn4+, we discuss the effect of the replacement on the electrical and properties of La0.7Sr0.3(Mn1-yCoy)O3
Another experiment was to synthesize pervoskite composite material for EMI shielding by mixing pervoskite with PU.
The conductivity of these composites were measured by a Four Point Probe . The shielding effect test was also made. The tests result indicated that with high conductivity and the best shielding effect we can have.
Experiment’s result shows that the resistance value of La0.7Sr0.3CoO3 is lowest(5.2×10-4 ohm) , and the composite material has lowest resistance value 1.2×102ohm with 25% La0.7Sr0.3CoO3 , at this time we got best shielding effect and the dB value is 13.

並列關鍵字

pervoskite ； EMI

參考文獻

Science 264, 413(1994).

【8】Kingery Bowen Uhlman, “Introduction to Ceramics”, Wiley (1976).

Friendeich, and J.Chzels, Phys, Rev. Lett. Vol.61, 2472 (1988).

【12】G. C. Xiong , Q. Li, H. L. Ju, S. N. Mao, L. Senapati, X. X. Xi, R. L.Greene, T.Venkatesan, “Giant Magnetoresistance in EpitaxialNd0.7Sr0.3MnO3-Delta Thin-Films”, Appl. Phys. Latt., Vol.66, (1995),pp.1427.

【13】J. C. Boettger, “High-Precision Calculation of The Equation of State and Crystsllographic Phase Stability for Aluminum”, Phys. Rev. B,53, No. 6, (1996), pp.3007.