【作者】 黄金田；

【导师】 赵广杰；

【作者基本信息】 北京林业大学 ， 木材科学与技术， 2004， 博士

【摘要】 为了改善木材的表面装饰特性或木质材料的导电功能和电磁屏蔽效能，进一步提高木材的综合利用率和使用价值，开发具有电磁波屏蔽效能的新型功能性木材和木质复合材料，本研究利用化学镀镍的方法，对木材化学镀的基本理论和化学镀液的配制、组成和影响因素进行了分析。研究了木材单板和刨花化学镀镍工艺技术，并对化学镀镍单板、化学镀镍刨花所制备的木质电磁屏蔽材料电磁屏蔽效能做了定量研究，研究了化学镀镍木材镀层的组织结构。 本研究结果归纳如下： 1．对镀液成分和工艺参数对木材化学镀镍沉积速率的影响进行了研究，主盐NiSO₄·6H₂O为50g／L、还原剂NaH₂PO₂·H₂O为60 g／L、络合剂HOCOCH（OH）₂CH₂CO为60 g／L、HOCOCH₂CH₂COOH为60 g／L情况下，当pH值为7.0～7.5、施镀温度为80℃、施镀时间为20 min时，可以得到比较理想的金属沉积速率。 2．随着金属镍沉积量的增加，化学镀镍单板的表面电阻率下降，导电性增加，化学镀镍单板的导电性具有各向异性。平行于纤维方向的表面电阻率要低于垂直于纤维方向的表面电阻率，在本实验所测定的范围内，化学镀镍单板垂直于纤维方向的表面电阻率是平行于纤维方向表面电阻率的3.45～1.34倍。化学镀镍杨木单板的电磁屏蔽效能可以达到31.8dB～51.4dB。由化学镀镍单板所制成的胶合板的电磁屏蔽效能与其化学镀镍单板的电磁屏蔽效能基本相同。 3．不同树种的抽提物含量对木材化学镀镍的影响较大，针叶材主要是树脂的含量，阔叶材主要是单宁的含量，这些抽提物容易造成镀液的分解。各个树种在经过抽提物的去除之后，可以实现木材的化学镀镍。 4．对杉木刨花进行化学镀镍，可以使刨花具有导电功能，由化学镀镍刨花所制成具有导电功能刨花板的密度在0.57g／cm³～1.12g／cm³之间变化。由较小表面电阻率的化学镀镍刨花制备的木质电磁屏蔽材料具有较小的体电阻率和良好的电磁屏蔽效能。运用较大热压压力的制板工艺，可以在一定程度上提高导电功能刨花板的电磁屏蔽效能。在5KHz～1500MHz的频率范围进行屏蔽效能测定，导电功能木质电磁屏蔽材料的电磁屏蔽效能可以达到21.26dB～43.31dB。 5．木材在化学镀镍时，金属镍不仅沉积在木材的表面，而且渗入到了木材的细胞腔和细胞壁的组织结构中。通过对化学镀镍单板的光学显微镜观察和分析，化学镀镍的单板在木材的细胞腔和细胞壁上的木射线组织、纹孔、管胞、木纤维上都有金属镍的沉积。树种不同，金属镍渗入木材的路径和组织结构也不相同。 6．首次对化学镀镍单板和化学镀镍刨花进行了XRD分析研究，化学镀镍的木材其纤维素的相对结晶度出现了下降的趋势，同时，化学镀镍刨花XRD分析证实了Ni（111）、Ni（200）和Ni（220）衍射峰的存在。化学镀镍单板和化学镀镍刨花的组织结构摘要对性能的影响是木材组织和金属镀层共同作用的结果。研究中还发现，除了主盐浓度、还原剂浓度、温度、pH值等因素外，木材基体的预处理过程同样也影响着镀层的组织结构。不同的预处理条件对木材化学镀镍层的含磷量、结晶化的程度以及镀层的组织结构都有很大的影响。更多还原

【Abstract】 To improve the wood surface decorate property, wooden material electricity conductive function and electromagnetic shielding property and to increase its utilization rate, the new functional wood and wooden composite material with electromagnetic shielding property are studied in this dissertation. The electroless plating is used in this dissertation. The basic theory of wood electroless nickel plating,solution composition and influencing factor are analyzed. The technology of nickel plating on wood veneers and particles are studied. Quantitative researches for electromagnetic shielding effectiveness of electromagnetic shielding wooden material made from nickel-plated veneers and particles are made. Organization structure of electroless nickel plating film are also studied.Research results are summed up as follows:1.The effect of plating solution composition and technology on wood electroless nickel plating depositing speed are studied .Under the conditions of main salt NiSO4 6 H2O is 50 g/L and reducing agent NaH2PO2 H2O is 60 g/L, Complexant mixture HOCOCH ( OH )2 CH2CO is 60 g/L and complexing agent HOCOCH2CH2COOH is 60 g/L, when pH is between 7.0 ~ 7.5, plating temperature is 80 癈, plating time is 20 min., we can get ideal metal deposition rate.2.Along with the increase of metal Nickel deposition, the surface resistivity of nickel-plated veneers decreases, while its conductivity increases and have anisotropy. The surface resistivity of parallel fiber direction is lower than that of perpendicular to fiber direction, in the scope of this laboratory measurements, the surface resistivity nickel-plated veneers of perpendicular to fiber direction is 1.34-- 3.45 times as high as that of parallel to fiber direction. The electromagnetic shielding effectiveness of nickel-plated poplar veneer can reach 31.8 decibels ~ 51.4 decibels. The electromagnetic shielding effectiveness of nickel-plated veneer is similar to plywood made from nickel-plated veneers.3.The extractive content from different tree species has great effect on electroless plating. The resin of Softwood and the tannic of hardwood cause plating liquid easily decompose. When extractive are excluded, wood electroless nickel plating can be done.4.Electroless nickel plating on Chinese Fir particles, make Chinese Fir particles have conductive function, the density of conductive particleboard made from nickel-plated particles changes between 0.57 g/cm3 ~ 1.12 g/cm3. When electromagnetic shielding material was produced using nickel-plated particles with smaller surface resistivity, it demonstrated smaller volume resistivity and better electromagnetic shielding effectiveness. A higher pressing pressure can improve electromagnetic shielding effectiveness of conductive particleboard to some extent. In experiments, electromagnetic shielding effectiveness can be measured in frequency 5 KHz -1500 MHz. It can reach 21.62 decibels -43.31 decibels.5.During plating nickel in wood, metal nickel not only deposit in wood surface, but also permeate into the cell wall and the cell cavity. In this experiment, the optical microscope was used to observe and analyze that nickel-plated veneer and we found Nickel depositing in the cell cavity, ray, pit, tracheae, and fiber of timber. When tree species are different, the route and structure that mental permeates into wood are also different.6.XRD has been used to study nickel-plated veneers and particles first time, the tendency of the relatively crystallization degree of cellulose of nickel-plated timber decreases, at the same time, XRD results show that Ni ( 111 ), Ni ( 200 )and Ni ( 220 ) diffraction summit exist in nickel-plated particles .The influence that structure of nickel-plated veneers and particles has on its properties is the result of timber micro structure and metal layer common role. In research, still discover that besides the factors such as main salt density, the density of reducing agent, temperature and pH value, the pretreatment course of timber matrix also affects structure of plating layer. Diffe更多还原