scholarly journals Structure and mechanism of electrical conductivity of resistive compositions for thick-film metal-ceramic heating elements

2019 ◽  
pp. 23-28
Author(s):  
Ye.Ya. Telnikov ◽  
O.G. Chernyshyn ◽  
O.M. Nedbailo ◽  
I.O. Khmara
Keyword(s):  
Electrical Conductivity ◽  
Thick Film ◽  
Thermal Inertia ◽  
Aluminoborosilicate Glass ◽  
Conducting Phase ◽  
Resistive Layer ◽  
Technical Problems ◽  
Conductive Phase ◽  
Metal Ceramic ◽  
Metal Borides

The work is devoted to the solution of scientific and technical problems of creating granular resistive thick films used in the manufacture of metal-ceramic heating elements. Using the method of mechanosynthesis, particles of transition metal borides and aluminoborosilicate glass of complex chemical composition were obtained. The electrical and thermal properties of thick-film metal-ceramic heating elements with a resistive layer based on modified particles of a conductive material are studied. The heating elements of the new generation are made by the method of thick-film technology, which is widely used in microelectronics in the manufacture of hybrid electronic circuits. Structurally, the thick-film heater is a base (metal with a dielectric coating, ceramics, glass, glass), which is consistently applied through a mesh stencil resistive paste and a dielectric protective coating. Direct heat transfer from the heating film to the substrate of the heat remover, due to the very low thermal inertia of the design, provides a quick exit of the heating element to the operating temperature. This feature of heaters opens new opportunities for their special use. The resistive layer is a complex heterogeneous disordered system containing regions with a metallic conductivity and dielectric portions. The electrical conductivity in such systems is a superposition of the metallic type — in the conducting phase and the activation phase — through the interlayer between the particles. The layer plays the role of a potential barrier for current carriers and largely determines the predominance of one of the electromigration mechanisms. Its composition and properties are formed during the interaction of molten glass with oxide films of particles of the conductive phase and doping of the compositions. Obtaining composite particles of the conductive phase in the process of preparation and heat treatment of materials allows you to purposefully change the properties of the nanoscale interlayer between these particles, which leads to the possibility of creating a group of materials and heating elements based on them with a complex of new properties.

scholarly journals Effect of V2O5Dopant on the Electrical Conductivity of RuO2Thick Film Resistors

1986 ◽  
Vol 12 (2) ◽  
pp. 111-117 ◽  
Author(s):  
M. S. Setty ◽  
R. F. Shinde
Keyword(s):  
Electrical Conductivity ◽  
Solid State ◽  
Charge Carrier ◽  
Thick Film ◽  
Solid State Reaction ◽  
Dopant Concentration ◽  
Sheet Resistivity ◽  
Conducting Phase ◽  
Extra Charge ◽  
Cationic Site

Thick film glaze resistors have been prepared using V2O5doped RuO2conducting phase. Different amounts of V2O5were incorporated into RuO2lattice by solid state reaction. Sheet resistivity decreased from 235 to 10 kΩ/Sq, with the increase in the dopant concentration from 2 to 6% wt. The conductivity, ‘σ’, was found to fit in the equation σ= KS(l-S), where S is the probability that a given cationic site will contain an extra charge carrier and K = 10-3mho-sq.

Pressure-Assisted Sintering of Buried Thick Film Resistors in LTCC

2015 ◽  
Vol 2015 (CICMT) ◽  
pp. 000239-000244
Author(s):  
Andreas Heunisch ◽  
Victor de Seauve ◽  
Torsten Rabe
Keyword(s):  
Thick Film ◽  
Electrical Resistance ◽  
Particle Distribution ◽  
Laser Diffraction ◽  
The Other ◽  
Sintering Process ◽  
Sheet Resistivity ◽  
Green Tape ◽  
Small Fluctuation ◽  
Conductive Phase

In this work, the effect of the pressure-assisted sintering process on buried thick film resistors integrated in LTCC multilayer has been studied. Four commercial resistor pastes with sheet resistivities between 10 kΩ and 10 MΩ/cm were analyzed. First they were characterized by SEM/EDX, XRD and Laser diffraction to determine composition and particle distribution. The pastes consist of isolating particles and of Ruthenium based particles that are supposed to build the conductive phase. The pastes were screen printed on LTCC green tape (DP 951) and buried in four layer laminates. Sintering was done in two ways, pressureless (PLS) and also pressure-assisted (PAS). The pressureless sintered resistors showed electrical resistance values roughly in the range of the nominal sheet resistivity and only relatively small fluctuation within one sample. The PAS samples on the other hand showed significantly higher resistances and larger deviations. The microstructure of the sintered resistors was again investigated by SEM and XRD. It seems that the resistivity is determined by the ratio of the two Ruthenium phases RuO2 and Pb2Ru2O6.5, where RuO2 has the higher conductivity. Buried resistors cannot be trimmed by a laser to adjust the resistance. But we discovered that a refiring step will reduce and normalize the resistivity of the PAS resistors significantly.

Aerosol jet printing of two component thick film resistors on LTCC

2013 ◽  
Vol 2013 (CICMT) ◽  
pp. 000240-000246 ◽  
Author(s):  
K. Swiecinski ◽  
M. Ihle ◽  
R. Jurk ◽  
E. Dietzen ◽  
U. Partsch ◽  
...  
Keyword(s):  
Particle Size ◽  
Thick Film ◽  
Glass Powder ◽  
New Technology ◽  
Organic Additives ◽  
Powder Mixtures ◽  
Conducting Phase ◽  
Aerodynamic Properties ◽  
Jet Printing ◽  
Aerosol Jet Printing

Aerosol jet printing is a rather new technology for the deposition of thick film structures offering high line and space resolution. This offers a high potential for miniaturization for thick film structures. The advantages of this technology could be shown with inks carrying single solid powder (e.g. silver, platinum, ceramic or glass powder). Challenging is printing of solid powder mixtures due to the differences in the aerodynamic properties of different powders. Those differences result in changes of the mixing ratio within the aerosol jet and therefore poor reproducibility in the final film properties is obtained. In this work, thick film resistors consisting of RuO2 with particle size < 1 μm as the conducting phase and different glass powders with particle size around 1 μm as the isolating phase were investigated. One glass had a density rather close to RuO2, the other glass significantly lower. Inks were made from RuO2/glass powder mixtures, a solvent and organic additives. After manufacturing the inks are printed on LTCC and the microstructures of the dried and the fired films were visualized by FIB preparation and SEM. The resistances as well as the temperature coefficients of the resistors were measured and compared to resistor films with an identical solid composition manufactured by conventional screen printing. The results of the obtained resistors are presented and discussed in terms of powder properties, ink dispersion and printing parameters.

scholarly journals Size Effects in Ruthenium-Based Thick-Film Resistors: Rutile vs. Pyrochlore-Based Resistors

1991 ◽  
Vol 14 (3) ◽  
pp. 163-173 ◽  
Author(s):  
M. Prudenziati ◽  
F. Sirotti ◽  
M. Sacchi ◽  
B. Morten ◽  
A. Tombesi ◽  
...  
Keyword(s):  
Size Effect ◽  
Thick Film ◽  
Sheet Resistance ◽  
Firing Temperature ◽  
Size Effects ◽  
Conductive Phase ◽  
Lower Sheet ◽  
Lower Sheet Resistance

The size effect, namely the change of sheet resistance, Rsas a function of resistor length, has been investigated in layers whose conductive phase evolves from Pb-rich (Ru-deficient pyrochlores) to Pb2Ru2O6.5and finally to RuO2by increasing the firing temperature. It is found that Bi diffusion from the terminations is responsible for lower sheet resistance values in shorter resistors whatever the conductive phase is. On the contrary, Ag diffusion is responsible for lower sheet resistance values in shorter resistors only in the case of ruthenate conductive grains while the reverse is observed in RuO2-based layers. Size effect can be suppressed with Pt/Au-based terminations provided that no Bi is contained and with Au-metallorganic-based contact provided that the peak firing temperature is not too high.

Improvement on Conductivity for Thick Film Aluminum Paste

2021 ◽  
Vol 21 (9) ◽  
pp. 4726-4734
Author(s):  
K. C. Chuang ◽  
Wen-Hsi Lee
Keyword(s):  
Electrical Conductivity ◽  
Thick Film ◽  
Low Cost ◽  
Glass Frit ◽  
Solid Content ◽  
Liquid Phase Sintering ◽  
Reducing Atmosphere ◽  
Al Powder ◽  
The Cost ◽  
Oxidation Effect

With the development of thick-film paste, silver and copper are circulating in the market as the electric conductive fillings currently. Unfortunately, the cost of silver is exceedingly high, while the copper has to be sintered in the reducing atmosphere. In this study, we proposed to exert aluminum as the filling due to its low cost, good electrical conductivity, and capability of being sintered in air. By means of the fracture mechanism of the oxidation layer of the Al surface and the liquid phase sintering, the Al paste with high solid content is used to implement high electrical conductivity. Based on that Al powder with large particle size tends to fracture easily, while it is easy for Al powder with small size to fill the gap, we mixed Al powder with large and small particle sizes at different proportion, so that the internal micro-structure and the oxidization are observed. However, when glass frit was added into mixed Al powder, the Al particles are wet by glass frit for bonding Al particles as well as inhibiting oxidation. Effect of the glass frit content and the solid content of Al paste on conductivity are investigated in this study. The sheet resistance of Al paste sintered at 850 °C for 10 min. can be reduced to 4.5 mΩ/□ when Al paste is formulated based on the mixed Al particles with proportion of big to small (4:1) at 10 wt% glass frit content and 80 wt% solid content.

Improvement on Conductivity for Thick Film Aluminum Paste

2021 ◽  
Vol 21 (9) ◽  
pp. 4596-4604
Author(s):  
K. C. Chuang ◽  
Wen-Hsi Lee
Keyword(s):  
Electrical Conductivity ◽  
Thick Film ◽  
Low Cost ◽  
Glass Frit ◽  
Solid Content ◽  
Liquid Phase Sintering ◽  
Reducing Atmosphere ◽  
Al Powder ◽  
The Cost ◽  
Oxidation Effect

With the development of thick-film paste, silver and copper are circulating in the market as the electric conductive fillings currently. Unfortunately, the cost of silver is exceedingly high, while the copper has to be sintered in the reducing atmosphere. In this study, we proposed to exert aluminum as the filling due to its low cost, good electrical conductivity, and capability of being sintered in air. By means of the fracture mechanism of the oxidation layer of the Al surface and the liquid phase sintering, the Al paste with high solid content is used to implement high electrical conductivity. Based on that Al powder with large particle size tends to fracture easily, while it is easy for Al powder with small size to fill the gap, we mixed Al powder with large and small particle sizes at different proportion, so that the internal micro-structure and the oxidization are observed. However, when glass frit was added into mixed Al powder, the Al particles are wet by glass frit for bonding Al particles as well as inhibiting oxidation. Effect of the glass frit content and the solid content of Al paste on conductivity are investigated in this study. The sheet resistance of Al paste sintered at 850 °C for 10 min. can be reduced to 4.5 mΩ/□ when Al paste is formulated based on the mixed Al particles with proportion of big to small (4:1) at 10 wt% glass frit content and 80 wt% solid content.

Influence of Glass Content on Microstructure and Electrical Conductivity of a β-Alumina Thick Film

2001 ◽  
Vol 206-213 ◽  
pp. 1223-1226 ◽  
Author(s):  
Jean-Marc Tulliani ◽  
L. Dessemond ◽  
P. Fabry ◽  
Claude Esnouf ◽  
Gilbert Fantozzi
Keyword(s):  
Electrical Conductivity ◽  
Thick Film ◽  
Glass Content

scholarly journals The Structure and Properties of Reactively Bonded Thick Film Gold Conductors

1978 ◽  
Vol 5 (1) ◽  
pp. 55-59 ◽  
Author(s):  
M. V. Coleman ◽  
G. E. Gurnett
Keyword(s):  
Electrical Conductivity ◽  
Copper Oxide ◽  
Thick Film ◽  
Adhesion Strength ◽  
Structure And Properties

The properties of reactively bonded gold conductors have been compared with a fritted gold conductor (DuPont 9260). Several different additives in the gold conductors were examined, including copper/copper oxide; copper plus cadium/germanium and copper cadium and bismuth.The adhesion strength of all the conductors was found to be superior to the fritted standard, but the electrical conductivity did not appear to be improved. These materials thus offer advantages where stronger adhesion is required or possibly, where the interface between conductor and substrate needs to be well-defined.

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