Improvement of electrical properties of wood by combination with ceramics

与陶瓷结合改善木材的电性能

• 批准号: 04660182
• 负责人: SOBUE Nobuo
• 金额: $ 1.34万
• 依托单位: Shizuoka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04660182/
• 关键词: Wood-ceramic composites; Metal alkoxides; Electrical properties; Carbonization; Addition of water glass; Resistivity; 熱伝導率; 焼成温度; セラミックスー木材複合化; チタン酸ナマリ; ジルコン酸ナマリ

This project deals with improvement of electrical properties of wood by forming wood-ceramics composites which have characteristic piezoelectricity and dielectricity and by carbonization of wood based materials which contain inorganic composites in order to control electrical and physical properties of the carbonized wood based material.A sol-gel process method was applied in order to form wood-inorganic composites. Metal alkoxides of Pb-Ti and Pb-Zr composites were impregnated in wet-sol state. Water glass and glassy balloon named shirasu balloon were added between 5 to 40 % in content to wood powder, and it was formed by using powder phenolic resin under pressure at 190ﾟC.The carbonization was made at 500 and 800ﾟC.The sedimentation of object ceramics was succeeded by the sol-gel method, but the desired improvement of electrical properties was not enough, because the temperature for aging of the gel was not enough to crystallize the object materials. However, the temperature 150ﾟC was the limit to prevent the thermal degradation of wood.The electrical resistivity of the carbonized materials depended on the temperature of carbonization. The resistivity was above 1 MOMEGA・cm by the treatment of 500ﾟC, and below 1 OMEGA・cm by the treatment of 800ﾟC.It increased remarkably by adding the small amount of the water glass, below 5% incontent. In the case of glass balloon, it increased above lMOMEGA・cm by adding 40% in content. Thermal conductivity was 0.1-0.2 W・m^<-1>・K^<-1>, which is almost equivalent to that of solid wood whose density is almost same. It was proved that the addition of inorganic substance was efficient to control resistivity of carbonized wood materials.As a future approach, the carbonization of the composites which are composed of wood powder and ceramics powder whose electrical and magnetic properties are characteristic will be efficient.

本课题采用溶胶-凝胶法制备了具有压电性和介电性的木材-陶瓷复合材料，并对含有无机复合材料的木质材料进行了碳化处理，以控制木质材料的电性能和物理性能。采用湿溶胶浸渍法制备了Pb-Ti和Pb-Zr复合材料的金属醇盐。在木粉中添加5 ~ 40%的水玻璃和玻璃球（称为shirasu balloon），并在190 ℃下用粉末酚醛树脂加压成型。在500 ℃和800 ℃下进行碳化。通过溶胶-凝胶法成功地沉积了目标陶瓷，但电性能的改善还不够，因为凝胶老化的温度不足以使目标材料结晶。但是，150 ℃是防止木材热降解的极限温度，碳化材料的电阻率取决于碳化温度。经500 ℃热处理后，电阻率大于1 Ω·cm，经800 ℃热处理后，电阻率小于1 Ω·cm。在玻璃球的情况下，增加40%的含量，其增加超过lMOMEGA·cm。导热系数为0.1-0.2 W·m^<-1>·K^<-1>，与密度相近的实木相当。结果表明，无机物的加入是控制木质材料电阻率的有效方法，而碳化法制备的木粉-陶瓷复合材料具有良好的电、磁性能，是今后的发展方向。