Mixed Solvents in Multi-Layer Ceramic Capacitors (MLCC) Elec-Tronic Paste and Their Effects on the Properties of Organic Vehicle

The copper end paste used in multilayer ceramic capacitors sintered in nitrogen atmosphere will lead to carbon residue of organic vehicle, which will lead to the reduction of electrode conduc-tivity and high scrap rate. With an attempt to leave no residue in the sintering, the compatibility of solvents and thickeners should be improved because it has an important influence on the hi-erarchical volatilization and carbon residue of organic vehicles. In this work, the volatility of different solvents was compared and several solvents were mixed in a definite proportion to prepare an organic vehicle with polyacrylate resins. The hierarchical volatility and solubility parameters of mixed solvents were adjusted effectively by changing proportions of different components, the thermogravimetric curves of resins and organic vehicles were measured by thermogravimetric analyzer, the effect of solubility parameter on the dissolvability of resins in the solvent and the residual of organic vehicles were studied. Results showed that the hierar-chical volatilization of solvents can be obtained by mixing different solvents; the intrinsic vis-cosity of the organic vehicle is higher and the thermal decomposition residue of polyacrylate resins is lower when the solubility parameters of mixed solvents and polyacrylate resins are closer. The low residual sintering of organic vehicles can be achieved by using the mixed solvent with hierarchical volatility and approximate solubility parameters as resins.

Pengaruh Suhu Pembakaran terhadap Karakteristik Listrik Keramik Film Tebal Berbasis Fe2O3–MnO–ZnO untuk Termistor NTC

Pembuatan keramik film tebal berbasis Fe2O3–MnO–ZnO untuk termistor NTC dari campuran Fe2O3 50% mol, MnO 25% mol, dan ZnO 25% mol telah dilakukan. Campuran serbuk Fe2O3, MnO dan ZnO yang telah digerus dicampurkan dengan organic vehicle (OV) untuk membentuk pasta. Kemudian pasta dilapiskan di atas substrat alumina menggunakan teknik screen printing untuk membentuk film tebal. Film tebal mentah yang diperoleh, dibakar pada suhu yang berbeda yaitu 1000°C, 1100°C, dan 1200°C selama 2 jam. Sebelum dilakukan pengukuran resistansi, film tebal dilapisi perak terlebih dahulu sebagai kontak logam. Resistansi termistor diukur pada suhu 40°C–200 oC dengan beda suhu sebesar 5 oC. Analisis struktur kristal dan struktur mikro film tebal masing – masing dilakukan dengan menggunakan X – Ray Diffraction (XRD) dan Scanning Electron Microscopy (SEM). Hasil analisis karakteristik listrik termistor yang dibakar pada suhu 1000 °C, 1100 °C, dan 1200 °C menghasilkan konstanta termistor berturut – turut sebesar 7700 K, 6995 K, dan 5701 K. Ketiga suhu pembakaran menghasilkan nilai konstanta termistor yang memenuhi kebutuhan pasar. Analisis struktur kristal menggunakan XRD menunjukkan bahwa keramik film tebal memiliki dua struktur yaitu struktur spinel kubik dan hematit heksagonal. Analisis struktur mikro menggunakan SEM menunjukkan bertambahnya ukuran butir sesuai dengan meningkatnya suhu pembakaran dengan ukuran butir film tebal yang dibakar pada suhu 1000 °C, 1100 °C, dan 1200 °C berturut – turut adalah 1.3 μm, 2.0 μm, dan 2.4 μm.

Preparation of BiFeO3-BaTiO3 Based Thick Films by Screen Printing

0.67BiFeO3-0.33BaTiO3thick films were prepared by screen printing pastes prepared by kneading the 0.67BiFeO3-0.33BaTiO3powder in a three-roll mill with an organic vehicle. The thick films were fired with Pt bottom electrodes and ZrO2substrates to investigate the influence of firing temperature. The microstructures and ferroelectric properties of the thick films were examined and compared with the bulk ceramics. A remanent polarization of 32.0 μC/cm2and coercive field of 28 kV/cm were obtained for a thick film with the addition of 0.5 wt% MnO that was fired at 1050 °C.

Influence of the organic vehicle and inorganic additives on the properties of thick film pastes for AlN

New conductor pastes for AlN as substrate material with fired films of a sheet resistance below 25 mOhm/sq were investigated. The pastes consist of AgPd as conductive phase for leach resistance. Other paste ingredients are glasses of matched composition for adhesion and densification properties, little amounts of inorganic additives and organic vehicles for film deposition. The latter has a significant influence on the paste deposition and the resulting film properties as well. In order to shine light into these relationship systematic rheological studies of the organic vehicle and the manufactured pastes were performed. The rheological investigations include measurements in rheological steady-state as well as dynamic experiments. In addition, the solder properties of the fired film were studied. FESEM analyses were performed on the surface of the fired films.

Multilayer Ceramic Capacitors Based on the PMN-PT-PFN Solid Solution

We present the technology of obtaining and the main properties of multilayered ceramic capacitors (MLCC) based on the PMN-PT-PFN solid solution. PMN-PT-PFN is the abbreviation of the material with general formula (1-y)[(1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3]-yPb(Fe1/2Nb1/2)O3. In our work the investigated material was PMN-PT-PFN with x=0.25, y=0.1 i.e. 0.9(0.75PMN-0.25PT)-0.1PFN. The powder of 0.9(0.75PMN-0.25PT)-0.1PFN has been obtained in three steps. In first step we obtained MgNb2O6. In second step FeNbO4 was obtained. In final third step the 0.9(0.75PMN-0.25PT)-0.1PFN was obtained from mixed powders MgNb2O6, FeNbO4, PbO and TiO2. Thick film pastes for obtaining MLCC were prepared by mixing of PMN-PT-PFN powder with organic vehicle and firing in furnace in the temperature range up to 1050°C. Platinum paste has been used as electrodes. The thickness of single layer was about 45 µm (including electrodes). For obtained MLCC XRD investigations were performed as well as investigations of microstructure, EDS and main dielectric properties.

Thick Film Metallization of AlN by Reactive Binders

The thick-film metallization of AlN has received considerable attention because of its potential applications in electronic packaging. Here we reported on the thick film metallization of AlN by reactive binders. The metallization paste of Ag was prepared with organic vehicle of castor oil, ethyl cellulose and beta-terpineol and reactive binders of TiB2 and Co3O4. The control of the paste viscosity was discussed by changing the dispersant content. Meanwhile effects of the components and sintering process on the thick film properties were investigated. The properties of metallization film were analyzed with XRD, SEM and electrical test. The adhesion strength and the electrical resistance of the film were 12.7MPa and 5.3mΩ/□ respectively when the paste composition of Ag, TiB2, Co3O4 and the organic vehicle was 72.8%, 1.5%, 0.7% and 25% and the film was sintered in air at 850°C for 15 minutes.

Preparation of MBi4Ti4O15 (M=Ba,Ca) Thick Films by Screen Printing

MBi4Ti4O15 (M=Ba,Ca) thick films were prepared by screen printing and firing using Pt bottom electrodes and ZrO2 substrates. Screen-printable pastes were prepared by kneading the MBi4Ti4O15 powder in a three-roll mill with an organic vehicle. The microstructures and electric properties of the thick films were examined in comparison with bulk ceramics. The remanent polarization of 6.2 9C/cm2 and coercive field of 130kV/cm were obtained for the CaBi4Ti4O15 thick film fired at 1130OC. The Curie points of MBi4Ti4O15 (M=Ba,Ca) thick films from dielectric peaks were 450OC and 790 OC for M=Ba and M= Ca.

Preparation of Bi4Ti3O12 Based Thick Films by Screen Printing

Bi4Ti3O12 based thick films were prepared by screen printing and firing using Pt bottom electrodes and ZrO2 substrates. The influence of excess Bi2O3 as sintering aid was investigated. Furthermore, substitution of Ti-site and Bi-site for V5+ and Nd3+ was performed. Screen-printable pastes were prepared by kneading the Bi4Ti3O12 based powder and Bi2O3 powder in a three-roll mill with an organic vehicle. The microstructures and ferroelectric properties of the thick films were examined in comparison with bulk ceramics. The remanent polarization of 9.6 μC/cm2 and coercive field of 64 kV/cm were obtained for the Bi3.0Nd1.0Ti2.99V0.01O12 thick film with 10 wt% of excess Bi2O3 fired at 1200OC.