scholarly journals The Role of Sacrificial and/or Protective Layers to Improve the Sintering of Electroactive Ceramics: Application to Piezoelectric PZT-Printed Thick Films for MEMS

Ceramics ◽  
2020 ◽  
Vol 3 (4) ◽  
pp. 453-475
Author(s):  
Hélène Debéda ◽  
Maria-Isabel Rua-Taborda ◽  
Onuma Santawitee ◽  
Simon Grall ◽  
Mario Maglione ◽  
...  
Keyword(s):  
Thick Film ◽  
Sacrificial Layer ◽  
Low Cost ◽  
Thick Films ◽  
Protective Layer ◽  
Protective Layers ◽  
Plasma Sintering ◽  
Wide Range ◽  
Spark Plasma ◽  
Pros And Cons

Piezoelectric thick films are of real interest for devices such as ceramic Micro-ElectroMechanical Systems (MEMS) because they bridge the gap between thin films and bulk ceramics. The basic design of MEMS includes electrodes, a functional material, and a substrate, and efforts are currently focused on simplified processes. In this respect, screen-printing combined with a sacrificial layer approach is attractive due to its low cost and the wide range of targeted materials. Both the role and the nature of the sacrificial layer, usually a carbon or mineral type, depend on the process and the final device. First, a sacrificial layer method dedicated to screen-printed thick-film ceramic and LTCC MEMS is presented. Second, the recent processing of piezoelectric thick-film ceramic MEMS using spark plasma sintering combined with a protective layer approach is introduced. Whatever the approach, the focus is on the interdependent effects of the microstructure, chemistry, and strain/stress, which need to be controlled to ensure reliable and performant properties of the multilayer electroceramics. Here the goal is to highlight the benefits and the large perspectives of using sacrificial/protective layers, with an emphasis on the pros and cons of such a strategy when targeting a complex piezoelectric MEMS design.

Feasibility of screen-printed PZT microceramics for Structural Health Monitoring piezocomposites applications

2013 ◽  
Vol 2013 (CICMT) ◽  
pp. 000020-000025
Author(s):  
Hélène DEBEDA ◽  
Riadh LAKHMI ◽  
Isabelle FAVRE ◽  
Jonathan ARGILLOS ◽  
Mario MAGLIONE ◽  
...  
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Sacrificial Layer ◽  
Low Cost ◽  
Thick Films ◽  
Impedance Analysis ◽  
High Porosity ◽  
Structural Health ◽  
Monitoring Applications ◽  
Screen Printing Technology

Using the association of the low-cost screen-printing technology with the sacrificial layer method, the feasibility of totally released piezoelectric thick-films microceramics of gold electroded PZT type is studied. After the deposition of the sacrificial layer on an alumina substrate and subsequent printing and drying of gold, PZT and gold layers, the final firing is performed at low temperature. This is followed by the releasing step of the Au/PZT/Au in diluted acidic solution. Impedance analysis shows that the electrical properties and electromechanical coefficients of poled PZT thick-films are still lower than those of PZT ceramics. This result is correlated to the high porosity rate of the PZT layer. However these piezoelectric microceramics present a good electromechanical behaviour and can be used as sensors when solicited by vibrations or as actuators to generate vibrations in a structure on which they are bonded. Moreover, the successful fabrication associated to a good electromechanical signature on a metallic test structure suggests Structural Health Monitoring applications.

scholarly journals Spark Plasma Sintering of Ceramics: From Modeling to Practice

Ceramics ◽  
2020 ◽  
Vol 3 (4) ◽  
pp. 476-493
Author(s):  
Michael Stuer ◽  
Paul Bowen ◽  
Zhe Zhao
Keyword(s):  
Spark Plasma Sintering ◽  
Ceramic Materials ◽  
Model Material ◽  
Operational Parameters ◽  
Key Factors ◽  
Engineering Approach ◽  
Plasma Sintering ◽  
Wide Range ◽  
Spark Plasma ◽  
Industrial Settings

Summarizing the work of nearly a decade of research on spark plasma sintering (SPS), a review is given on the specificities and key factors to be considered in SPS of ceramic materials, based on the authors’ own research. Alumina is used primarily as a model material throughout the review. Intrinsic inhomogeneities linked to SPS and operational parameters, which depend on the generation of atomistic scale defects, are discussed in detail to explain regularly observed inhomogeneities reported in literature. Adopting an engineering approach to overcome these inherent issues, a successful processing path is laid out towards the mastering of SPS in a wide range of research and industrial settings.

Plastic Deformation of Silicon Nitride Nano-Ceramics

2007 ◽  
Vol 352 ◽  
pp. 189-192 ◽  
Author(s):  
Toshiyuki Nishimura ◽  
Xin Xu ◽  
Naoto Hirosaki ◽  
Rong Jun Xie ◽  
Hidehiko Tanaka
Keyword(s):  
Plastic Deformation ◽  
Silicon Nitride ◽  
High Energy ◽  
Sintering Additives ◽  
Plasma Sintering ◽  
Wide Range ◽  
Spark Plasma ◽  
Short Time ◽  
Si3n4 Ceramics ◽  
Stress Activation

A commercial silicon nitride powder with sintering additives was ground by high-energy milling to reduce particle size. Nanometer sized powder was obtained. The powder was densified for short time by spark plasma sintering to prevent grain growth. Nanometer-grained Si3N4 ceramics were obtained. Plastic deformation of the Si3N4 nano-ceramics has been studied in compression over a wide range of strain rates and temperatures. The experimental results revealed that a transition in stress exponent, n, at each temperature. The n value decreased from ~ 2 to ~ 1 with increasing applied stress. Activation energy was also different for the two regions, decreasing from 858.2 kJ/mol in the n ~ 2 region to 571.8 kJ/mol in the n ~ 1 region. Effect of sintering additives on plastic deformation was also discussed.

Advance of Sintering Methods of High Purity Alumina Ceramics

2016 ◽  
Vol 703 ◽  
pp. 76-80 ◽  
Author(s):  
Qing Bo Tian ◽  
Jin Shan Dai ◽  
Li Na Xu ◽  
Xiu Hui Wang
Keyword(s):  
High Pressure ◽  
Spark Plasma Sintering ◽  
High Purity ◽  
Alumina Ceramics ◽  
Grain Coarsening ◽  
Plasma Sintering ◽  
Wide Range ◽  
High Pressure Sintering ◽  
Conventional Sintering ◽  
Spark Plasma

The sintering of alumina ceramics with high-purity has gained much attention due to their wide range applications. The improved sinteirng methods, such as the spark plasma sintering, super-high pressure sintering, two-step sintering, and so on, have advantages on the decreasing the sinteirng temperature or inhibiting the grain coarsening, compared with the conventional sintering.

Plasma Display Materials

MRS Bulletin ◽  
2002 ◽  
Vol 27 (11) ◽  
pp. 898-902 ◽  
Author(s):  
Kinzo Nonomura ◽  
Hidetaka Higashino ◽  
Ryuichi Murai
Keyword(s):  
Large Scale ◽  
Protective Layer ◽  
Operating Conditions ◽  
Protective Layers ◽  
Blue Phosphor ◽  
Wide Range ◽  
Plasma Display ◽  
Deterioration Mechanism ◽  
Discharge Gas ◽  
Gas Efficiency

AbstractRecent trends in the development of plasma display panels (PDPs) are reviewed in this article with special emphasis on materials. New developments in the panel structure, discharge gases and phosphors used, and drive methods have improved many of the display characteristics over a wide range of operating conditions. As a result, much progress has been seen in large-scale panel development; for example, 50-in. and 61-in. PDPs have been commercialized. Improvements in phosphor longevity, discharge gas efficiency, and characteristics of the protective layers can be attributed in part to materials solutions. The longevity of the blue phosphor has been improved by the development of new materials and a greater understanding of the phosphor deterioration mechanism. The luminous efficiency has been greatly increased by the use of high-density Xe gas. The protective-layer characteristics have been improved as a result of advancements in processes, materials, and analytical methods.

scholarly journals Effect of Sintering Mechanisms On The Mechanical Behaviour of SiC And Kaoline Reinforced Hybrid Aluminium Metal Matrix Composite Fabricated Through Powder Metallurgy Technique

2021 ◽  
Author(s):  
V.S.S Venkatesh ◽  
Ashish B Deoghare
Keyword(s):  
Mechanical Properties ◽  
Spark Plasma Sintering ◽  
Automobile Industry ◽  
Metal Matrix ◽  
Low Cost ◽  
Microwave Sintering ◽  
Phase Identification ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Sintering Mechanisms

Abstract Hybrid metal matrix composites with naturally available and low-cost reinforcements made tremendous demand in the automobile industry to fabricate parts like Pistons, Automobile body and brake discs because of the superior properties of HMMC compared to monolithic Aluminium. Present work focusses on the fabrication of Al-10% SiC-4% Kaoline HMMC by using conventional sintering, Microwave sintering and Spark Plasma Sintering (SPS) techniques. To reveal the phase identification and the distribution of reinforcements, Fabricated composites were investigated by using XRD, SEM integrated with an EDS analyser. Tensile, Compression and hardness tests were performed as per ASTM standards to study the effect of sintering mechanisms on the fabricated HMMC specimens. Results reveal that an enhancement of 13.3 % in U.T.S and 11.7 % Compression strength was observed in the Spark Plasma Sintered HMMC when compared to conventional sintered composite specimens because of lesser sintering temperature, time and the absence of intermetallic compounds in the Spark Plasma Sintering process. The formation of the Al2Cu intermetallic compound was identified in the XRD pattern of conventionally sintered Al-10% SiC-4% Kaoline HMMC sample due to the high sintering time and temperature which leads to inadequate mechanical properties. The fractured surface of tensile specimens reveals the presence of cleavages on the conventionally sintered HMMC which conforms the brittle fracture, and the existence of dimples on the Microwave sintered and Spark Plasma Sintered samples which signify that the ductile mode of failure in HMMC samples. Out of the three sintering techniques, Spark Plasma Sintering exhibits superior mechanical properties and lesser porosity levels.

scholarly journals Sodium potassium niobate (K0.5Na0.5NbO3, KNN) thick films by electrophoretic deposition

RSC Advances ◽  
2015 ◽  
Vol 5 (6) ◽  
pp. 4698-4706 ◽  
Author(s):  
Morgane Dolhen ◽  
Amit Mahajan ◽  
Rui Pinho ◽  
M. Elisabete Costa ◽  
Gilles Trolliard ◽  
...  
Keyword(s):  
Thick Film ◽  
Electrophoretic Deposition ◽  
Low Cost ◽  
Thick Films ◽  
Lead Free ◽  
Piezoelectric Response ◽  
Potassium Niobate ◽  
Sodium Potassium ◽  
Sodium Potassium Niobate

Lead free thick film obtained by low cost electrophoretic deposition having piezoelectric response of ~40 pC N−1.

Influence of Coated Composite Powders on the Properties of ZrB2-YAG-Al2O3 Ceramics

2014 ◽  
Vol 602-603 ◽  
pp. 451-456
Author(s):  
Jie Guang Song ◽  
Xiu Qin Wang ◽  
Fang Wang ◽  
Shi Bin Li ◽  
Gang Chang Ji
Keyword(s):  
Weight Gain ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Composite Powder ◽  
Raw Materials ◽  
Protective Layer ◽  
Ceramic Materials ◽  
Composite Powders ◽  
Plasma Sintering ◽  
Spark Plasma

ZrB2, YAG and Al2O3 are widely applied because of some excellent performances, but ZrB2 is easily oxidized in the high-temperature air. To make the ZrB2 ceramics obtain better oxidation resistance, high-density ZrB2-YAG-Al2O3 ceramics were prepared. The influences of coated composite powders on the densification and the oxidation resistance of ZrB2-YAG-Al2O3 ceramics were investigated. The 80wt%ZrB2-YAG-Al2O3 multiphase ceramic materials from different composite raw materials with the spark plasma sintering technique were successfully prepared. The densification of ZrB2-YAG-Al2O3 ceramics with Al2O3-Y2O3 composite powder coated is easier than that of ZrB2-YAG-Al2O3 ceramics with YAG-Al2O3 powder mixed. The reaction temperature is lower than the 1100¡æ for synthesizing YAG powders from Al2O3-Y2O3 composite powders. The weight gain are increased with increased the oxidation temperature. B2O3 is reacted with Al2O3 to form Al18B4O33, Al18B4O33 is melted and coated on the surface of ceramics to form a protective layer for the oxidation resistance of ceramics at high temperature. The oxidation weight gain of ZrB2-YAG-Al2O3 ceramic with Al2O3-Y2O3 composite powder coated is lower than that of ZrB2-YAG-Al2O3 ceramic with YAG-Al2O3 powder mixed.

scholarly journals Electrical properties of graphite-glass thick-film resistors

Circuit World ◽  
2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Tomasz Matusiak ◽  
Arkadiusz Dabrowski ◽  
Leszek Golonka
Keyword(s):  
High Temperature ◽  
Temperature Coefficient ◽  
Thick Film ◽  
Sheet Resistance ◽  
Low Cost ◽  
Glass Mass ◽  
Temperature Coefficient Of Resistance ◽  
Content Type ◽  
Wide Range ◽  
Typical Temperature

Purpose The purpose of this paper is to present the properties of thick-film resistors made of novel pastes prepared from glass and graphite. Design/methodology/approach Graphite-based resistors were made of thick-film pastes with different graphite-to-glass mass fraction were prepared and examined. Sheet resistance, temperature coefficient of resistance, impact of humidity and short-term overload were investigated. The properties of the layers fired in atmospheres of air at 550°C and nitrogen at 875°C were compared. Findings Graphite-based resistors with various graphite-to-glass ratios made possible to obtain a wide range of sheet resistance from single O/square to few kO/square. These values were dependent on firing atmosphere, paste composition and the number of screen-printed layers. The samples made of paste with 1:1 graphite-to-glass ratio exhibited the temperature coefficient of resistance of about −1,000 ppm/°C, almost independently on the firing atmosphere and presence of a top coating. The resistors fired in the air after coating with overglaze, exhibited significantly lower sheet resistance, reduced impact of humidity and improved power capabilities. Originality/value In this paper, graphite-based resistors for applications in typical high-temperature cermet thick-film circuits were presented, whereas typical graphite-based resistors were fabricated in polymer thick-film technology. Owing to very low cost of the graphite, the material is suitable for low-power passive circuits, where components are not subjected into high temperature, above the typical temperature of operation of standard electronic components.

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