NTC (negative temperature coefficient) thermistors are semiconductor ceramics whose resistance decreases with increasing temperature, making them essential components in various temperature sensing applications. Typically, ceramic materials are sintered at high temperatures exceeding 1,150°C. However, in laminated devices incorporating internal electrodes, co-sintering can lead to cracking and mechanical failure due to mismatches in the thermal expansion coefficients between the ceramic layers and metal-based electrodes. Moreover, the use of noble metal electrodes increases production costs. To address these challenges, a low-temperature sintering approach is required. Previous studies have demonstrated that incorporating glass frit can reduce the sintering temperature of ceramics, although this often results in increased electrical resistance. In this study, NiMnCoO₄ (NMC) ceramics, as a representative NTC thermistor composition, were prepared with the addition of 10 wt% glass frit. To mitigate the resulting increase in resistivity, trace amounts (1 wt%) of various metal oxides, including CuO, ZnO, and MnO, were introduced. Among these, the addition of CuO notably decreased both the resistivity and B constant values. In contrast, MnO had little effect on resistivity, while ZnO led to an increase. With respect to the B25/85 constant, samples containing MnO and ZnO exhibited higher values than those without metal oxide additives. These findings indicate that the incorporation of 1 wt% CuO is effective in reducing the increased resistivity in NMC ceramics subjected to low-temperature sintering via glass frit addition.

NTC thermistors are essential components widely used for temperature sensing in various electronic sensor applications. However, conventional NTC thermistor ceramics typically require high sintering temperatures above 1150℃, necessitating the use of high-cost noble metal electrodes such as palladium (Pd) or platinum (Pt), which increases the overall manufacturing cost. In this study, low-melting-point oxides were successfully introduced as sintering aids to reduce the sintering temperature of NiMnCoO₄-based semiconducting ceramics. As the additive content increased, the B constant and average grain size exhibited an increasing trend, while the sample containing 5 wt% additives showed the lowest room-temperature resistivity. Furthermore, samples sintered at 1000℃ demonstrated slightly higher room-temperature resistivity and B constant values compared to those sintered at 1150℃. These results confirm that the addition of low-melting-point oxides is effective in lowering the sintering temperature of NiMnCoO₄ ceramics, suggesting the potential for reducing production costs and improving design flexibility in thermistor fabrication.

In this study, the effect of vanadium oxide (V₂O₅) content and pre-sintering atmosphere on sealing property of glass frit that consisted of V₂O₅-BaO-ZnO-P₂O₅-TeO₂-CuO-Fe₂O₃ SeO₂ was investigated by XPS (X-ray photoelectron spectroscopy). The content of V₂O₅ was changed to 15, 30, and 45 mol%, and the pre-sintering was carried out in air and N₂ condition, respectively. XPS analysis conducted before and after laser irradiation with identical sample. Before laser treatment, glass frits that were pre-sintered at air condition showed both V₄₊and V₅₊, but the valence state was changed to V₅₊ after laser irradiation when the glass frits contained 30 and 45 mol% V₂O₅; this change led to non-adhesive property. On the other hand, glass frits that were pre-sintered at N₂ condition exhibited only V₄₊ and it showed fine adhesion irrespective of the V₂O₅ content. As a result, the existence of V₄₊ seems to be a major factor for controlling the adhesive property of glass frit for laser sealing.

One of the important issues for fabricating the microelectronic display devices such as FED, PDP, and VFD is to obtain a high vacuum level inside the panel. In addition, sustaining the initial high vacuum level permanently is also very important. In the conventional packing technology using a tabulation method, it is not possible to obtain a satisfiable vacuum level for a proper operation. In case of FED, the poor vacuum level results in the increase of operating voltage for electron emission from field emitter tips and an arcing problem, resultantly shortening a life time. Furthermore, the reduction of a sealing process time in the PDP production is veryimportant in respect of commercial product. The most probable method for obtaining the initial high vacuum level inside the space with such a miniature and complex geometry is a vacuum in-line sealing which seals two glass plates within a high vacuum chamber. The critical solution for the vacuum sealing is to develop a frit glass to avoid the bubbling or crack problems during the sealing process at high temperature of about 400℃ under the vacuum environment. In this study, the suitable frit power was developed using a mixture of vitreous and crystalline type frit powders, and a vacuum sealed CNT FED with 2 inch diagonal size was fabricated and successfully operated.

In this study, we developed a lead-free P_{2}`O_{5}`-V_{2}O_{5}-ZnO glass frit for sealing OLED using laser irradiation. The frit satisfied the characteristics required for laser sealing such as low glass transition temperature, low coefficient of thermal expansion (CTE), high water-resistance, and high absorption at the wavelength of the laser beam. Ceramic fillers were added to the glass frit in order to further reduce and match its CTE with that of the commercial glass substrate. The addition of Zirconium Tungsten Phosphate (ZWP) to the frit yielded the most desirable results, reducing the CTE to 45.4×10^{-7}/℃, which is very close to that of the glass substrate (44.0×10^{-7}/℃). Successful formation of a solid sealing layer was observed by optical and scanning electron microscopy.

We investigated dielectric relaxation properties of 0.95(Na0.5K0.5)NbO3-0.05BaTiO3 ceramics byaddition (0∼0.3 wt%) of (Ba,Ca)SiO3 glass frit. All composition of 0.95(Na0.5K0.5)NbO3-0.05BaTiO3 added(Ba,Ca)SiO3 glass frit showed the same crystallographic properties, coexistence of orthorhombic andtetragonal phase. By increasing addition of (Ba,Ca)SiO3 glass frit, the Curie temperatures of0.95(Na0.5K0.5)NbO3-0.05BaTiO3 ceramics were decreased, whereas maximum dielectric constants of0.95(Na0.5K0.5)NbO3-0.05BaTiO3 ceramics were dramatically increased. Especially the deviations of Curietemperature 0.95(Na0.5K0.5)NbO3-0.05BaTiO3 ceramics were increased by increasing amount of(Ba,Ca)SiO3 glass frit, and it indicated that 0.95(Na0.5K0.5)NbO3-0.05BaTiO3 ceramics added (Ba,Ca)SiO3glass frit have relaxor characteristics.

The front electrode should be used to make solar cell panel so as to collect electron. The front electrode is used by paste type, printed on the Si-solar cell wafer and sintered at about 800℃. The paste is composed Ag powder and glass frit which make the ohmic contact between Ag electrode and n-type semiconductor layer. From the previous study, the Ag electrodes which used two commercial glass frit of Bi-system were so different on the interface resistance. The main composition of them was Bi-Zn-B-Si-O and few additives added in one of them. In this study, glass frit was made with the ratio of Bi2O3 and ZnO on the main composition, and then paste using glass frit was prepared respectively. And, also, the paste using the glass frit added oxide additives were prepared. The change of interface resistance was not large with the ratio of Bi2O3 and ZnO. In the case of G6 glass frit, 78 wt% Bi2O3 addition, the interface resistance was 190 Ω and most low. In the glass frit added oxide, the case of Ca increased over 10 times than it of G6 glass frit on the interface resistance. It was thaught that after sintering, Ca added glass frit was not flowed to the interface between Ag electrode and wafer but was in the Ag electrode.

Citations

• Properties of Silicon Solar Cells with Local Back Surface Field Fabricated by Aluminum-Silicon Eutectic Alloy Paste
  Jae-Wook Choi, Sungeun Park, Soohyun Bae, Seongtak Kim, Se Jin Park, Hyomin Park, Yoonmook Kang, Hae-Seok Lee, Donghwan Kim
  Current Photovoltaic Research.2016; 4(4): 145.     CrossRef

(Na,K)NbO3-based piezoelectric ceramics were synthesized by a liquid phase sintering method with a selected glass frit. The effects of the content of the glass frit and the sintering temperature on the microstructure and the electrical properties of the samples were investigated. With the 0.1 wt% of glass frit content, (Na0.52K0.44Li0.06)(Nb0.84Ta0.10Sb0.06)O3 (NKL-NTS) ceramics showed the maximum values of the relative density (99.1%) and the electro-mechanical coupling factor (kp: 0.32) at the sintering temperature of 1,050℃. It might mean that a liquid phase sintering with a suitable glass frit having the lower flow temperature could improve the relative density and the piezoelectric properties.

Two kind of Ag-pastes were prepared for integrating the bulk Si solar cell. One is the Ag-paste with Pb-based glass frit and the other is that with Bi-based glass frit. The pastes were the mixture of 84 wt% Ag, 2 wt% glass frit, 11 wt% solvent of buthyl cabitol acetate, and 2 wt% additives. After fabricating the Ag-pastes, they was coated on a SiN(x)/n+/p- stacks of a commercial mono-Si solar cell. The solar cell efficiency was 17.6% in the case of the Pb-based Ag-paste. However that was 16.2% in the solar cell integrated with the Bi-based Ag-paste. The lower performance in Bi-based Ag-paste was caused by the higher series resistance and the lower shunt resistance in comparison with the Pb-based Ag-paste.

Carbon nanotubes (CNTs) have been significantly used for the field emitters for display applications. However, the lifetime of CNT emitters which are formed by screen printing technique is not guaranteed yet, because the constituents in CNT paste affect the lifetime of CNTs. The CNT pastes for screen printing are normally composed of organic vehicles (nitro cellulose, ethyl cellulose, etc) and additives (glass frits, indium tin oxide (ITO), etc) with CNTs. In this study, the effects of constituents in CNT pastes on the lifetime and emission characteristics of CNTs were investigated by thermal and electrical analysis. Use of glass frits worsened the lifetime and electron emission of CNTs. However, an addition of ITO to CNT paste rather improved the lifetime of CNTs. Degradation of CNTs was small when nitro cellulose was used in CNT paste as an organic vehicle.

Citations

• Improved Field Emission Properties of Carbon Nanotube Paste Emitters Using an Electrically Conductive Graphite Binder
  Hanbin Go, Si Eun Han, Hyunjea Lee, Cheol Jin Lee
  ACS Applied Electronic Materials.2024; 6(5): 3554.     CrossRef
• Enhancement of Photoelectrochemical Performance of Ag@ZnO Nanowires: Experiment and Mechanism
  Yu Cai, Chengbao Yao, Jie Yuan
  Journal of Nanomaterials.2020; 2020: 1.     CrossRef

The effect of lead free glass frit compositions on the properties of thick film conductor and resistor pastes were investigated. Two types lead free frits, HBF-A(without Bi2O3) and HBF-B(with Bi2O3) were made from SiO2, B2O3, Al2O3, CaO, MgO, Na2O, K2O, ZnO, MnO, ZrO2, Bi2O3. And Ag based conductor pastes and RuO2 based resistor paste were prepared by mixed with these frits and functional phase(Ag and RuO2), and organic vehicle. The properties of thick film conductor and resistor sintered at 850℃ were studied after printing on Al2O3 substrate. The morphology of the sintered films surface were SEM and EDS were carried out to analysis the chemical composition on resistor surface and state of Ru atom in frit matrix.

Citations

• Effect of Screen Printing and Sintering Conditions on Properties of Thick Film Resistor on AlN Substrate
  Bon Keup Koo
  Journal of the Korean Ceramic Society.2014; 51(4): 344.     CrossRef