Bonding of zero-shrink LTCC with alumina ceramics

2015 ◽  
Vol 27 (4) ◽  
pp. 157-163
Author(s):  
Jakub Somer ◽  
Michal Štekovič ◽  
František Urban ◽  
Josef Šandera ◽  
Ivan Szendiuch
Keyword(s):  
Thick Film ◽  
Ceramic Materials ◽  
Alumina Ceramics ◽  
Compression Method ◽  
Content Type ◽  
Adhesive Layers ◽  
Electrical Systems ◽  
Curing Cycle ◽  
Bonding Method ◽  
Printed Patterns

Purpose – The purpose of this paper is to focus on a description of reliable bonding technique of zero-shrink low-temperature co-fired ceramic (LTCC) and alumina ceramics. LTCC is widely used for manufacturing electrical systems in 3D configuration. LTCC substrates were so far bonded with alumina ceramics using additional adhesive layers with subsequent firing or curing cycle. With the advent of the zero-shrink LTCC substrates, it is now possible to bond unfired substrates with other fired substrates, for example fired LTCC or alumina substrates. Alumina substrate in combination with LTCC brings advantages of good thermal conductivity for usage in heating elements or packaging. Design/methodology/approach – The test structure contains a thick-film pattern for verification of the compatibility of the bonding process. We have used two methods for bonding the substrates: cold chemical lamination (CCL) and thermo compression method, using a dielectric thick-film paste as the adhesive. Optical microscopy, scanning electron microscopy and electric testing of the screen-printed patterns were used for verification of the bonding quality. Findings – The thermo-compression method gave poor results in comparison with the CCL method. The best quality of lamination was achieved at room temperature combined with low pressure for both types of bonding materials. In addition, a possibility of using this bonding method for sensor fabrication was investigated. The ceramic pressure sensor samples with a cavity were created. Originality/value – The possibility of bonding two different ceramic materials was investigated. A new approach to ceramic bonding showed promising results with possible use in sensors.

Environmental tests of embedded thin- and thick-film resistors in comparison to chip resistors

Circuit World ◽  
2014 ◽  
Vol 40 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Wojciech Steplewski ◽  
Andrzej Dziedzic ◽  
Janusz Borecki ◽  
Grazyna Koziol ◽  
Tomasz Serzysko
Keyword(s):  
Thin Film ◽  
Thick Film ◽  
Electrical Resistance ◽  
Printed Circuit Boards ◽  
Base Material ◽  
Forming Process ◽  
Content Type ◽  
Thin Film Resistors ◽  
Embedded Resistors ◽  
The Impact

Purpose – The purpose of this paper is to investigate the influence of parameters of embedded resistive elements manufacturing process as well as the influence of environmental factors on their electrical resistance. The investigations were made in comparison to the similar constructions of discrete chip resistors assembled to standard printed circuit boards (PCBs). Design/methodology/approach – The investigations were based on the thin-film resistors made of NiP alloy, thick-film resistors made of carbon or carbon-silver inks as well as chip resistors in 0402 and 0603 packages. The polymer thick-film resistive films were screen-printed on the several types finishing materials of contact terminations such as copper, silver, and gold. To determine the sensitivity of embedded resistors versus standard assembled chip resistors on environmental exposure, the climatic chamber was used. The measurements of resistance were carried out periodically during the tests, and after the exposure cycles. Findings – The results show that the change of electrical resistance of embedded resistors, in dependence of construction and base material, is different and mainly not exceed the range of 3 per cent. The achieved results in reference to thin-film resistors are comparable with results for standard chip resistors. However, the results that were obtained for thick-film resistors with Ag and Ni/Au contacts are similar. It was not found the big differences between resistors with and without conformal coating. Research limitations/implications – The studies show that embedded resistors can be used interchangeably with chip resistors. It allows to save the area on the surface of PCB, occupied by these passive elements, for assembly of active elements (ICs) and thus enable to miniaturization of electronic devices. But embedding of passive elements into PCB requires to tackle the effect of each forming process steps on the operational properties. Originality/value – The technique of passive elements embedding into PCB is generally known; however, there are no detailed reports on the impact of individual process steps and environmental conditions on the stability of their electrical resistance. The studies allow to understand the importance of each factor process and the mechanisms of operational properties changes depending on the used materials.

Characterization and applicability of Sm0.9Sr0.1CoO3-δ in oxygen sensors

2014 ◽  
Vol 31 (3) ◽  
pp. 154-157 ◽  
Author(s):  
Katarina Cvejin ◽  
Libu Manjakkal ◽  
Jan Kulawik ◽  
Krzysztof Zaraska ◽  
Dorota Szwagierczak
Keyword(s):  
Seebeck Coefficient ◽  
Thick Film ◽  
Bulk Sample ◽  
Solid State Reaction Method ◽  
Oxygen Sensors ◽  
Potentiometric Sensors ◽  
X Ray Diffraction ◽  
Content Type ◽  
Thermal Analyzer ◽  
Perovskite Material

Purpose – This paper aims to investigate different properties of synthesized perovskite Sm0.9Sr0.1CoO3-δ and its potential for application in potentiometric oxygen sensors. Design/methodology/approach – The powder was obtained through solid-state reaction method and characterized by thermogravimetric/differential thermal analyzer and X-ray diffraction. It was used for both making a paste and pressing into rods for sintering. The prepared paste was deposited on alumina and yttria-stabilized zirconia substrates, by screen printing. Thick film conductivity, bulk conductivity and Seebeck coefficient of sintered rods were measured as a function of temperature. An oxygen concentration cell was fabricated with the screen-printed perovskite material as electrodes. Findings – Electrical conductivity of the bulk sample and thick film increases with the increase in temperature, showing semiconductor-like behavior, which is also indicated by relatively high values of the measured Seebeck coefficient. Estimated values of the activation energy for conduction are found to be of the same magnitude as those reported in the literature for similar composition. An investigation of Nernstian behavior of the fabricated cell confirmed that Sm0.9Sr0.1CoO3-δ is a promising material for application in oxygen potentiometric sensors. Originality/value – Gas sensor research is focused on the development of new sensitive materials. Although there is scarce information on SmCoO3-δ in the literature, it is mostly investigated for fuel cell applications. Results of this study imply that Sr-doped SmCoO3-δ is a good candidate material for oxygen potentiometric sensor.

Thick Film Pastes for Power Applications

2013 ◽  
Vol 2013 (CICMT) ◽  
pp. 000155-000161
Author(s):  
Christina Modes ◽  
Melanie Bawohl ◽  
Jochen Langer ◽  
Jessica Reitz ◽  
Anja Eisert ◽  
...  
Keyword(s):  
Thick Film ◽  
Electric Vehicles ◽  
Hybrid Electric Vehicles ◽  
Thermal Dissipation ◽  
Automotive Applications ◽  
Electrical Systems ◽  
Electronic Circuitry ◽  
And Performance ◽  
New Applications ◽  
Thick Film Technology

Electronic circuits made by thick film technology are commonly used today in electronic circuitry for automotive applications. Densely packed multi-layer hybrid circuits are very well established for motor and transmission management in standard gasoline fuelled vehicles. As automotive technology shifts from mechanical systems to electrical systems and toward more electrically driven vehicles, such as hybrid electric vehicles and full electric vehicles, thick film systems need to be adapted to fit the challenges and needs of these new applications. The following is a description of a new set of thick film pastes, both precious and base metal, which have attributes and performance suitable for power electronics in automotive applications. The materials provide a means to use common thick film technology to build power circuits to meet the new needs, such as high current carrying capacity and thermal dissipation.

Design and integration of a piezoelectric vibrating device in an LTCC structure

2017 ◽  
Vol 34 (3) ◽  
pp. 121-126
Author(s):  
Darko Belavič ◽  
Andraž Bradeško ◽  
Tomaz Kos ◽  
Tadej Rojac
Keyword(s):  
Thick Film ◽  
Piezoelectric Actuator ◽  
Mechanical Vibration ◽  
Research Work ◽  
Pressure Sensors ◽  
Dissipation Factor ◽  
Driving Voltage ◽  
Research Activity ◽  
Content Type ◽  
Converse Piezoelectric Effect

Purpose In this contribution, the design and integration of a piezoelectric vibrating device into low-temperature, co-fired ceramic (LTCC) structures are presented and discussed. The mechanical vibration of the diaphragm was stimulated with a piezoelectric actuator, which was integrated onto the diaphragm. Three different methods for the integration were designed, fabricated and evaluated. Design/methodology/approach The vibrating devices were designed as an edge-clamped diaphragm with an integrated piezoelectric actuator at its centre, whose role is to stimulate the vibration of the diaphragm via the converse piezoelectric effect. The design and feasibility study of the vibrating devices was supported by analytical methods and finite-element analyses. Findings The benchmarking of the ceramic vibrating devices showed that the thick-film piezoelectric actuator responds weakly in comparison with both the bulk actuators. On the other hand, the thick-film actuator has the lowest dissipation factor and it generates the largest displacement of the diaphragm with the lowest driving voltage. The resonance frequency of the vibrating device with the thick-film actuator is the most sensitive for an applied load (i.e. mass or pressure). Research limitations/implications Research activity includes the design and the fabrication of a piezoelectric vibrating device in the LTCC structure. The research work on the piezoelectric properties of integrated piezoelectric actuators was limited. Practical implications Piezoelectric vibrating devices were used as pressure sensors. Originality/value Piezoelectric vibrating devices could be used not only for pressure sensors but also for other type of sensors and detectors and for microbalances.

Stability of electrical properties for mechanically exposed thick- and thin-film resistors on flexible substrates

2017 ◽  
Vol 29 (1) ◽  
pp. 54-58 ◽  
Author(s):  
Andrzej Dziedzic ◽  
Pawel Osypiuk ◽  
Wojciech Steplewski
Keyword(s):  
Thin Film ◽  
Electrical Properties ◽  
Thick Film ◽  
Flexible Substrates ◽  
Stability Parameters ◽  
Content Type ◽  
Thin Film Resistors ◽  
Mechanical Factors ◽  
The Stability ◽  
Almost All

Purpose The paper aims to verify the influence of mechanical factors (longitudinal elongation at constant stretching velocity, constant elongation strain and cyclic compressive and tensile stresses) on the electrical properties of thin-film and polymer thick-film resistors on flexible substrates. Design/methodology/approach Kapton foil was used as a substrate for all test samples. Designed resistive structures were made with the aid of two polymer thick-film resistive inks or OhmegaPly Ni-P resistive foil. Two different topologies – the horseshoe and triangular – were used. These topologies should have the opposite stability parameters. Findings Almost all presented data confirm the influence of the topology of resistors on stability of their electrical properties. The resistive materials applied for test structures also affect the stability under various mechanical exposures. Originality/value In general, the largest changes were caused by longitudinal elongation at constant stretching velocity, whereas other tests caused smaller changes of electrical properties. The measurements confirm the influence of topology on stability of electric properties.

Free SHS-Compression Method for Producing Large-Sized Plates from Ceramic Materials

2019 ◽  
Vol 60 (3) ◽  
pp. 261-263 ◽  
Author(s):  
A. M. Stolin ◽  
P. M. Bazhin ◽  
A. S. Konstantinov ◽  
P. A. Stolin ◽  
A. D. Prokopets ◽  
...  
Keyword(s):  
Ceramic Materials ◽  
Compression Method

The value of decompression for acute experimental spinal cord compression injury

1980 ◽  
Vol 53 (6) ◽  
pp. 749-755 ◽  
Author(s):  
Eugen J. Dolan ◽  
Charles H. Tator ◽  
Laszlo Endrenyi
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Compression ◽  
Functional Recovery ◽  
Cord Compression ◽  
Compression Method ◽  
Compression Injury ◽  
Inclined Plane ◽  
Content Type ◽  
Plane Technique ◽  
The Relationship

✓ A clip compression method was used to produce acute spinal cord compression injury in rats. The force and duration of the spinal cord compression were independently varied, and functional recovery of the cord was assessed using the inclined plane technique. Mathematical modeling produced a curve defining the relationship between force, duration, and functional recovery for each week after injury. The study clearly showed the beneficial effect of decompression and that increasing either the force or duration of compression, or both, caused a reduction in recovery.

Universal trimming of polymer thick film resistors

2015 ◽  
Vol 32 (2) ◽  
pp. 45-51 ◽  
Author(s):  
Busi Rambabu ◽  
Y. Srinivasa Rao
Keyword(s):  
Thick Film ◽  
Polyvinyl Chloride ◽  
High Voltage ◽  
Design Methodology ◽  
Content Type ◽  
Research Implication ◽  
First Time ◽  
Practical Implications

Purpose – The purpose of this paper is to study high-voltage interactions in polymer thick-film resistors, namely, polyvinyl chloride (PVC)-graphite thick-film resistors, and their applications in universal trimming of these resistors. Design/methodology/approach – The authors applied high voltages in the form of pulses and impulses of various pulse durations and with different amplitudes to polymer thick-film resistors and observed the variation of resistance of these resistors with high voltages. Findings – The paper finds that high voltages can be used for trimming of polymer thick-film resistors in both directions, i.e. upwards and downwards. Research limitations/implications – The research implication of this paper is that polymer thick-film resistors can be trimmed downwards or upwards practically using this method. Practical implications – The practical implications of this paper is that one can trim the polymer thick-film resistors, namely, PVC–graphite thick-film resistors, in both directions, i.e. upwards and downwards, by using this method. Originality/value – The value of the paper is in showing that high voltages can be used to trim downwards and also upwards in the case of polymer thick-film resistors. This type of trimming is called universal trimming, developed first time for polymer thick-film resistors.

Performance assessment of controller designed for electrical systems with second order dynamics

2020 ◽  
Vol 39 (6) ◽  
pp. 1345-1362
Author(s):  
K. Ghousiya Begum
Keyword(s):  
Design Methodology ◽  
Transfer Functions ◽  
Direct Synthesis ◽  
Synthesis Method ◽  
Second Order ◽  
Reference Tracking ◽  
Content Type ◽  
Electrical Systems ◽  
Error Index ◽  
Index Value

Purpose An assessment technique that analyzes the servo and regulatory characteristics of the proportional integral derivative controller is designed for time-delayed second-order stable processes. Design/methodology/approach The minimum theoretical error expression for integral of the absolute errors (IAE_o) is obtained from the preferred servo and regulatory transfer functions dependent on the step changes in reference and load variables. Findings The error-based index is outlined to estimate the controller that is derived using internal model-based control or direct synthesis method. The ratio between derived IAE_o and the IAE_actual gained from the loop response that experiences step input variations gives rise to a dimensionless error index. This error index measures the behaviour of the controller by considering the index value. If the error index value is larger than 0.8, then the effort taken by the controller is good or else retuning is expected. Originality/value The efficacy of the index to validate the controller is verified by applying on a few second-order electrical processes. The results are simulated for both reference tracking and load rejection tasks to demonstrate the rationality of the presented index.

Effect of Sintering Temperature on the Densification Mechanism of Al2O3-Al Metal Ceramics via the Powder Metallurgy Method

2018 ◽  
Vol 279 ◽  
pp. 104-108 ◽  
Author(s):  
Jie Guang Song ◽  
Lin Chen ◽  
Yun Xiang ◽  
Yue Liu ◽  
Xin Shuang Guo ◽  
...  
Keyword(s):  
Mass Fraction ◽  
Sintering Temperature ◽  
Mixing Time ◽  
Performance Testing ◽  
High Strength ◽  
Ceramic Materials ◽  
Powder Metallurgy Method ◽  
High Plasticity ◽  
Alumina Ceramics ◽  
Densification Mechanism

Alumina ceramics with good mechanical and corrosion resistance are the ones of the most widely used engineering ceramics. The aluminum has high strength, high conductivity and high plasticity etc. so that aluminum ceramics are used in more and more industries. In this paper, the mass fraction of 25% Al2O3 powder and the mass fraction of 75% Al powder were mixed in the blender. Mixer speed is100r/min with mixing time of 3.5 h. Forming, sintering and a series of processes for preparing the alumina/aluminum metallic ceramic materials, through performance testing and analysis, found that the density of the sample firstly increased and then decreased with the increase of sintering temperature. A melting point is close to the sintering temperature and the density of the cermet can be made relatively high. When the sintering temperature is about 600°C and 700°C, the macro performance of sample is better. The cermet is sintered at 700°C and its microstructure is relatively better.

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