B料MLCC镍内电极浆料质量性能研究

镍内电极浆料是贱金属MLCC产品的主要原材料之一,其技术难度高,国产化率低。目前国内贱金属B料MLCC镍内电极浆料已经研制成功,通过与进口同类浆料的性能分析与对比试验,结果表明国产贱金属B料MLCC镍内电极浆料的生产技术水平、工艺使用性能、电性能和可靠性能均能够满足MLCC产品的工艺使用要求及行业标准要求,并达到了与进口同类浆料同等的质量水平。     

Effect of Cr additions on the electrical properties of Ni–BaTiO3 ultra-thin multilayer capacitors

Multilayer ceramic capacitors based on BaTiO₃ dielectric compositions and Ni inner electrodes have complex interfacial reactions that impact the continuity of the inner electrode microstructure. Previously we demonstrated that through the addition of Cr to Ni, a significant improvement in the continuity of ultra-thin Ni electrodes in Ni–BaTiO₃ multilayer capacitors could be achieved. Here, the effect of the Cr addition to the nickel electrode pastes is studied with regard to the electrical properties. Low-field electrical measurements demonstrate no major differences between Cr doped Ni and undoped Ni. However, high-field measurements show a significant decrease to the total capacitor resistance. Under a critical electrical bias the conductivity significantly increases due to a Fowler–Nordheim tunneling conduction though the interfacial Schottky barrier at the dielectric–electrode interface; the onset voltage of this conduction is much lower than with the undoped nickel. Based on these results, we evaluate criteria for the selection of an appropriate refractory metal in order to improve the Ni electrode continuity.     

超小型片式多层陶瓷电容器内电极印刷工艺研究

该文介绍了在超小型片式电容器内电极印刷中影响质量的诸多因素,并分析其原因,具体探讨了丝网网框、网布、丝印制版工艺对印刷质量的影响.结果表明,通过选用合适的网框、网布,使用镜面处理感光胶的制版技术,可以达到理想的印刷效果及合适的镍电极层厚度.     

10℃法则与多层瓷介电容器的贮存寿命试验

GJB/Z 148-2006《军用电容器选择与应用指南》提出的10℃法则,是表征元件寿命与温度应力关系的简便估算方式,它对于估算实际的使用条件下多层瓷介电容器的长期贮存寿命有着重要的意义。列举了国外对于多层瓷介电容器激活能的研究成果,并通过经典的温度加速模型与10℃法则的关系,证明了10℃法则对于多层瓷介电容器的加速寿命试验的适用性;同时认为根据10℃法则进行贮存寿命试验所得到的结果比使用经典的温度加速模型得到的结果更加可信。     

高Q值铜内电极MLCC的研制

以铜为内电极和端电极,制备了NPO MLCC.研究了陶瓷粉体成分、内电极材料和烧结工艺对所制MLCC性能的影响.结果表明:选用Mg-Si-O3系瓷粉匹配纯铜内电极浆料,在弱还原气氛保护下进行低温(900～1 020℃)烧结,所制MLCC样品电性能良好,成本低,其中,0603规格10pF样品在1 GHz下的Q值高达60、...     

影响直流高压MLCC表面放电的因素

通过悬浮内电极排布、加大端头间距、使用自制专用表面整理剂对高压MLCC表面彻底清洁等工艺措施,对高压MLCC表面放电现象有很大改善,并显著提高了其耐电压性能。采用单悬浮电极排布、3.2mm端头间距,并用自制专用表面整理剂处理,制作1808规格、容量100pF、工作电压3000V的NP0特性MLCC产品,在6000V下没有表面放电现象,击穿电压在10000V以上。     

单分散二氧化硅超细颗粒的制备

通过控制反应速度,以氨催化水解醇介质中的正硅酸乙酯(TEOS)制备得到了400±20nm的单分散二氧化硅超细颗粒。反应首先在低浓度TEOS下形成并完善晶核,再在高浓度下促使晶核强制生长,最后经陈化得到粒径分布集中、单分散二氧化硅超细颗粒。以制备的SiO2作为添加剂制作Y5V特性MLCC,其性能优于进口SiO2。     

Multifunctional BaTiO3-(Bi0.5Na0.5)TiO3-based MLCC with high-energy storage properties and temperature stability

BaTiO₃-(Bi_0.5Na_0.5)TiO₃ (BTBNT)-based multilayer ceramic capacitor (MLCC) chips with the inner electrodes being Ag0.6/Pd0.4 are prepared by a roll-to-roll casting method. The BTBNT-based MLCC chips with ten-dielectric layers can be sintered very well at a low temperature of 1130°C via two-step sintering (TSS). X-ray diffraction (XRD) and transmission electron microscope (TEM) results show that MLCC chips are a core-shell structure with two phases coexistence. The core exhibits a tetragonal phase at room temperature and then gradually changes into a cubic phase when the temperature increases above T_c (175°C). While, the shell exhibits a pseudocubic phase at all tested temperature from 25°C to 500°C. BTBNT-based MLCC chips exhibit a broad temperature stability and meet the requirement of Electronic Industries Association (EIA) X9R specifications. In terms of energy storage performance, a large discharge energy density of 3.33 J/cm³ can be obtained at 175°C under the applied electric field of 480 kV/cm. Among all tested temperature ranging from −50°C to 200°C, the energy efficiency of all chips is higher than 80%, even under a high applied electric field. The experimental results indicate that this novel BTBNT-based X9R MLCCs can be one of the most promising candidates for energy storage applications, especially operated in high temperature.     

制作Ni-MLCC用Ba(TiZr)O3系陶瓷微结构与电特性的关系

Ba(TiZr)O3(BZT)-Ho-Mn系陶瓷材料烧结温度的提高会引起微结构的变化,当对其进行再氧化处理时,则会引起电气特性的改变,作者对其两者之间的关系进行了研究。通过烧成圆片制成样品对其微结构进行观察,发现晶粒随烧结温度的升高而逐渐增大。对于同一组成,随着晶粒长大,介电常数的最大温度系数向较高温度侧移动;晶粒生长将加速Mn化合价的改变和渗入到晶粒内的程度;介电特性与微结构、组成分布和晶粒内的掺杂浓度等均有关系。     

Ni/Cu电极MLCC烧成工艺的研究

通过各项工艺对比实验,研究了烧成工艺参数对成品性能的影响。给出了最佳工艺参数:烧结温度为1280～1300℃,保温2h,用N2/H2/H2O的混合气控制P(O2)为10–8～10–10MPa,回火温度900～1100℃,保温2～5h,回火气氛氧含量(5～50)×10–6;1000℃以上的升降温速率控制在2～4℃/min。在此工艺条件下,选用合适的烧炉,可以得到性能合格的Ni/Cu电极MLCC。