纳米油墨在电子工业中的应用

纳米油墨在许多行业得到推广应用,如防伪印刷、包装印刷、纺织品印花、电子线路层印刷等,都有效地提高了产品质量和性能。文章主要介绍纳米油墨在电子工业的应用前景。     

一种用于导电油墨的特种铜粉制备研究

特种导电油墨是全印制电路技术开发与应用的关键之一。本文报道了利用硫酸铜、碳酸钠、抗坏血酸等为原料,通过固相反应获得纳米非球形铜粉方法。通过SEM、EDS分析表明,获得的产物为一种柱状的高纯铜粉,直径大约500nm,可以作为全印制电路技术用高性能特种油墨的开发。     

3D printing Si3N4-bonded SiC refractories fabricated using colloidal films-containing slurries based on non-spherical SiC and Si powders

Stable slurries for Si₃N₄-bonded SiC refractories for direct ink writing (DIW) were successfully prepared from a mixture of non-spherical silicon carbide (SiC) and silicon (Si) powders with an average particle size of D₅₀ = 41.98 μm. The rheological properties and printability of slurries prepared using polyvinyl alcohol (PVA; 4–16 wt %) or hydroxypropyl methylcellulose (HPMC, 0.5–2 wt.%) were investigated with the effect of sintering temperature on the mechanical performance, phase, and microstructure of Si₃N₄-bonded SiC refractory products. The results indicated that slurries prepared with the HPMC solution showed better printability than those prepared with the PVA solution because colloidal films formed by HPMC in slurries play a role in encasing particles, preventing solid−liquid separation and contributing to plasticity and lubrication, which guarantees the smooth extrusion and homogeneity of slurries. The successful printing of SiC–Si slurries is not only related to proper viscosity, yield value, and shear thinning characteristics but it is also crucial for maintaining the homogeneity of slurries under extrusion pressure. Optimal SiC–Si slurries containing 52 vol % SiC–Si and 1.5 wt% HPMC exhibited proper viscosity, shear thinning, and homogeneity characteristics during printing. The obtained specimens achieved the best printing performance with height and section retention rates of 98.7% and 97.6%, respectively. When sintered at 1450 °C, Si₃N₄ fibres grow further and reach a diameter of 342.5 nm, the nitriding rate is 92.43%, the fibres tend to form a full network structure, and the mechanical properties of Si₃N₄-bonded SiC products are the best.     

Ablation behaviour of Csf/ZrB2-SiC composites fabricated by direct ink writing and reactive melt infiltration

Pitch-based short carbon fibres reinforced C_sf/ZrB₂-SiC composites were fabricated by direct ink writing of short carbon fibres, followed by slurry impregnation and reactive melt infiltration. Ablation behaviour of the C_sf/ZrB₂-SiC composite was studied by air plasma test. It is indicated that the skeleton of the oriented short carbon fibres provides heat diffusion channels. Consequently, temperatures at the ablation surface are as low as ∼1730 ^oC and ∼2000 ^oC respectively at 4 MW/m² and 5 MW/m². The composite presents outstanding ablation-resistant performance with a linear recession rate of ∼ − 0.04 µm/s and mass recession rate of ∼ − 3.40 mg/s at 4 MW/m², ∼ − 0.17 µm/s and ∼ 3.58 mg/s at 5 MW/m². It is revealed that the fibres area and matrix area of the composite present different ablation mechanisms. The fibres area is ablated severely, while the matrix area presents excellent ablation-resistance with continuous ZrO₂-SiO₂ protective layer.     

Competing Effects of Radio Frequency Fields on Carbon Nanotube/Resin Systems: Alignment versus Heating

This work shows that radio-frequency (RF) fields can simultaneously align carbon nanotubes (CNTs) dispersed in a resin and induce Joule heating to cure the resin. The timescales of alignment and curing using RF heating are numerically computed and compared at different field strengths in order to determine a temperature where alignment happens before the matrix crosslinks. Composites are experimentally fabricated at the desired target temperature and are optically analyzed and quantified; the CNT network is successfully aligned in the direction of the applied electric field. This methodology can be used to create composites where the local alignment can be varied across the sample. Composites fabricated using RF fields have higher electrical conductivity in the direction of the aligned CNTs than an oven-cured, randomly aligned sample. Also, RF-cured nanocomposites exhibit higher tensile strength and modulus in the direction of alignment compared to an oven-cured sample. Finally, it is further demonstrated how this methodology can be coupled with a direct ink writing additive manufacturing process to induce alignment in any desired direction, even orthogonal to the shear forces in the extrusion direction.     

基于印刷技术制备柔性微型电容器的研究进展

柔性微型超级电容器作为一种新兴的储能器件,具有充放电速度快、功率密度大、循环寿命长等优点,在可穿戴电子设备领域中具有良好的应用前景。为实现柔性显示器、晶体管、射频识别装置及可穿戴设备等柔性电子产品的协同发展,针对微型超级电容器中存在的关键问题,阐述了制备微型超级电容器的凹版印刷法和丝网印刷方法,认为丝网印刷法工艺简单、耗时短、可集成、易实现工业化生产,该技术制备的叉指结构可在有限平面内实现离子转移;针对导电油墨的核心印刷技术,分析了无机系、有机系及复合型导电油墨研究近况,总结了复合型导电油墨制备的微型超级电容器电容特性,对其应用前景进行展望。     

纳米填料对高光彩喷墨纸涂层材料性能的影响

分别以二氧化硅、三种自组装改性二氧化硅、碳酸钙和高岭土为填料制备高光彩喷墨纸涂层材料，研究了填料对高光彩喷墨纸高光表层涂层材料分辨率和光泽度的影响；另外，还研究了不同粒径的自组装改性纳米二氧化硅对光泽度和墨迹干燥时间的影响。发现通过合适的阳离子聚合物自组装改性且粒径约为80nm的二氧化硅，是一种良好的高光彩喷墨纸涂层填料，对应的涂层具有良好的光泽度和较快的墨迹干燥速度。     

水性油墨印刷新闻纸碎浆工艺的探讨

对含30％水性油墨印刷新闻纸的ONP碎浆工艺进行了研究。碎浆效果的评价采用如下方法：将混合ONP碎解后，所得浆料立刻进行超级洗涤处理，然后测量超级洗涤处理后浆料的白度和ERIC，用它们来衡量油墨剥离程度与不可逆再沉积的总体效果。研究结果表明：在中性条件下，碎浆效果比较理想；碎浆前添加表面活性剂吐温-80或吐温-20能显著改善碎浆效果，超级洗涤处理后浆料的白度能够达到近56％ISO。     

基于双常数Kubelka-Munk理论光谱配色模型的研究

针对专色油墨配色这一薄弱环节,对光谱配色方法进行了研究,使得在提高印刷速度与质量的同时,保证了色彩再现的一致性。首先建立基于双常数KubelkaMunk理论的光谱配色数学模型,给出其各参数的求解方法;然后用丙烯颜料模拟印刷油墨进行专色油墨配色实验,将标准色样光谱反射率代入数学模型中得到标准色样的浓度配方;最后根据油墨浓度配方得到实际色样,通过计算实际色样与标准色样的色差和光谱近似程度验证光谱配色精度。本配色模型所得到的实际色样和标准色样的色差小于3,说明可以满足一般产品的配色;GFC值约等于1,说明实际色样的光谱反射率曲线和标准色样的光谱反射率曲线吻合情况较好。基于双常数Kubelka-Munk理论光谱配色模型的配色精度准确性较高,具有实用性。     

纸张毛细管半径测量的新方法

利用印刷过程中油墨渗透深度随印刷压力和印刷速度的变化关系,建立了纸张毛细管半径方程,用实验方法测量了印刷过程中油墨在纸张中的渗透深度,由印刷压力、印刷速度、渗透深度测量值实现了纸张毛细管半径的定量测量。