Zoran Samardžija's research while affiliated with Jožef Stefan Institute and other places

Publications (108)

Article
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The green transition initiative has exposed the importance of effective recycling of Nd-Fe-B magnets for achieving sustainability and foreign independence. In this study, we considered strip-cast, hydrogenated, jet-milled Nd-Fe-B powder as a case study to explore the potential for selective chemical leaching of the Nd-rich phase, aiming to extract...
Article
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Super-hydrophobic surfaces and coatings have stimulated a great deal of research, with the aim being to achieve better wetting properties. Factors such as surface chemistry and roughness play an important role in changing the surface energy, which in turn leads to changes in the wettability. Here, we have analysed the time dependence of the oxide l...
Preprint
Full-text available
Super-hydrophobic surfaces and coatings have stimulated a great deal of research, with the aim to achieve better wetting properties. Factors such as surface chemistry and roughness play an important role in changing the surface energy, which in turn leads to changes in the wettability. Here, we have analysed the time dependence of the oxide layer a...
Article
Full-text available
0.67[Pb(Mg 1/3 Nb 2/3 )O 3 ]-0.33[PbTiO 3 ] (PMN-33PT) epitaxial thin films were prepared by pulsed-laser deposition (PLD) using ceramic targets, enriched with PbO (and MgO). The phase composition and crystal structure were analyzed by high-resolution X-ray...
Article
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Ammonia (NH3) present in biological fluids is biomarker for several disease states. In this work the well-known interaction between polyaniline (PANI) and NH3 was used for the fabrication of an amperometric sensory platform to detect aqueous NH3 at neutral i.e. biological pH. Understanding PANI's electrochemical synthesis and redox behaviour in aci...
Article
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The consumption of critical raw materials, especially those in permanent magnets of Nd–Fe–B and Sm–Co-type, has significantly grown in the past decade. With predictions on further electrification growing exponentially the demand for these materials will even increase. This implies that efforts in assuring sustainability must involve recycling from...
Article
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This study focused on the crystal and electronic structures of a newly discovered phase in the Al-Cr-Sc system. The latter two species do not mix in a binary alloy, but can be alloyed with aluminium in the vicinity of the Al2−xCrxSc composition, where 0.3 < x < 0.5. After preparation of the pure constituents via arc melting, high-temperature anneal...
Article
This work deals with the influence of gallium addition on the constitution and formation of the phases in the Al-rich corner of the Al–Mn system during casting. Al-rich binary Al–Mn and ternary Al–Mn–Ga alloys were cast into a copper mould with a cavity diameter of 5 mm. The microstructures of the produced alloys were characterized by scanning elec...
Article
Worldwide, the production of plastics is increasing, and plastic pollution in aquatic environments is a major global concern. Under natural conditions, plastic weathers to smaller pieces called microplastics (MP), which come in various shapes, with fibers often being the most common in freshwater sediments. The hyporheic zone, an ecotone between su...
Article
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Titanium dioxide (TiO2) nanotubes obtained by the anodic oxidation of titanium metal foils can be used for the photocatalytic degradation of organic pollutants. The aim of our study was to determine the influence of the titanium foil’s surface treatment on the final morphology of the TiO2 nanotubes and their photocatalytic activity. In our experime...
Article
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The presence of plastics in the environment is currently one of the most pressing global environmental problems. Microorganisms start to form biofilms on plastic surfaces when they first come in contact with the biosphere; however, these interactions and processes are little understood, especially in freshwaters. This study aimed to better understa...
Article
Sintered Nd-Fe-B permanent magnets are the first choice for electro-mechanical devices that rely on hard-magnetic materials to provide strong magnetic fields in a variety of operating conditions. However, the limitations of conventional powder-metallurgy methods regarding the complexity of the magnet’s geometry restrict the design freedom for elect...
Article
B has been proposed to extend persistent luminescence from minutes to > 10 h in Eu, Dy, and B co-doped Sr4Al14O25 (S4A7EDB) by facilitating the incorporation of Eu²⁺ and Dy³⁺ into adjacent Sr sub-lattice sites and enabling energy transfer between them. To evaluate additional influences of B on the kinetics of microstructural evolution and dopant di...
Article
Full-text available
Pulsed-laser deposition was used to prepare Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) thin films on (LaNiO3)/SrTiO3 substrates. We found that the bottom electrode has an immense influence on the properties of the overgrown active layer. Specifically, we found that the use of LaNiO3 (LNO) as the electrode material strongly stabilizes the perovskite phase and...
Article
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A closed loop of recovering rare-earth elements and transition metals from Nd–Fe–B magnets with the total re-use of the electrolyte using a facile electrolysis-selective precipitation procedure.
Article
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This study investigated the mineralogical and isotopic composition of groundwater and precipitation to identify and constrain geochemical processes within stacked Pliocene and Triassic aquifers in the Velenje coal basin. Scanning electron microscopy combined with energy-dispersive X-ray spectroscopic analysis revealed that suspended matter in the P...
Article
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Recycling of end‐of‐life Nd–Fe–B magnets is an important strategy for reducing the environmental dangers associated with rare‐earth mining and overcoming the supply risks associated with the rare‐earth elements. In this study, a novel concept for recycling of sintered Nd–Fe–B magnets by directly recovering the matrix Nd 2 Fe 14 B grains is presente...
Article
This investigation deals with the influence of calcium, strontium and zinc on the formation of primary, metastable quasicrystals in Al-Mn-Si alloys as these can enhance the mechanical properties of alloys. The synthesized alloys were cast into a copper mould. The castings were characterized using standard tools for studying microstructure. The Al-M...
Article
The present communication reports the variation in surface characteristics of bilayered coating of phosphate free bioactive glass (PFBG) on SS316L substrate at simulated conditions, w.r.t both pH and temperature, to understand the suitability of the same for load bearing applications. The coated substrates were subjected to both physiological (7.4)...
Article
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Ceramic pigments emitting long afterglow have enormous potential for emerging lighting applications that consume zero energy from the power grid. One of the most efficient compounds is strontium aluminate, when co-doped with 2 rare-earth elements — an optically active emitter, such as Eu2+, and an auxiliary ion, such as Dy3+— and B. To date, spectr...
Article
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The magnetic properties of the recycled hydrogenation disproportionation desorption recombination (HDDR) Nd-Fe-B powder, doped with a low weight fraction of DyF 3 nanoparticles, were investigated. Spark plasma sintering (SPS) was used to consolidate the recycled Nd-Fe-B powder blends containing 1, 2, and 5 wt.% of DyF 3 grounded powder. Different p...
Article
Growth of Pb(Mg1/3Nb2/3)O3–33PbTiO3 thin films by pulsed-laser deposition directly on non-conductive SrTiO3 substrates for d33-mode energy harvesters (EHs) was studied, as they offer a higher figure-of-merit than d31-mode EHs. It was found that a high defect density, present in the film grown at 0.13 mbar, is manifested in the form of splitting of...
Article
This study confirms that the stable icosahedral quasicrystal (iQc) phase Al65Cu20Fe15 (iQc–AlCuFe) can serve as a substrate for the nucleation of the metastable iQc–AlMnSi phase formed in rapidly solidified Al–Mn–Si alloys. The results reveal that a continuous, thin layer of the metastable iQc–AlMnSi phase can be formed on a stable iQc–AlCuFe parti...
Article
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An Al–Mn alloy with additions of copper, magnesium, and silicon was prepared and cast into a copper mold. It contains in situ-formed icosahedral quasicrystals (iQCs), as confirmed by electron backscatter diffraction. The aim of this work is to present the mechanical and corrosion properties of this alloy and compare its properties with some convent...
Article
Fe69±3Pd31±3 nanowires (NWs) with lengths of a few microns and diameters of 200 nm were synthesized via template-assisted pulsed electrodeposition into alumina-based templates. The as-deposited Fe69±3Pd31±3 NWs exhibited α-Fe (bcc-solid solution of Fe, Pd) nanocrystalline structure as seen from the x-ray diffraction (XRD), that got confirmed by tra...
Article
We investigated the effects of dual doping of SnO2 varistor ceramics with 1 mol% CoO and different amounts of Nb2O5 (0.1 - 2 mol%) on the formation of twin boundaries, microstructure development and electrical properties. Nb2O5 addition shifts densification to higher temperatures (up to 1430 °C), producing microstructures composed of twinned SnO2 g...
Article
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We prepared three Al–Mn-based alloys with different copper, magnesium and silicon contents by casting into cylindrical copper molds. All the alloys exhibited primary metastable quasicrystals (QCs). In order to confirm the presence of either primary decagonal QCs (dQCs) or icosahedral QCs (iQCs) and to determine their compositions, the castings were...
Article
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The surface water geochemistry and carbon cycling studied here depend mainly on geological composition of the river catchment. The investigated surface waters in the river Pesnica catchment that are heavily hydromorphologicaly altered (reservoirs, channelization, land melioration systems) represent waters inflenced by chemical weathering of carbona...
Article
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Quantitative EPMA-WDS microanalyses were applied for the compositional characterisation of complex perovskite ferroelectrics based on cerium-doped barium titanate, a solid solution between lead-magnesium-niobate/lead-titanate and niobium-doped barium- bismuth-titanate. The analyses were optimized for high analytical sensitivity, precision and an ul...
Conference Paper
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Aluminium alloys with primary icosahedral quasicrystals (iQCs) were prepared in this work. Alloys of Al-Mn-Cu-Mg-Si with different content of manganese were prepared in chamber furnace and cast into a copper mould with 5 mm diameter. Light microscopy (LM) was used for the characterization of microstructure and evaluation of possible presence of QCs...
Article
Optimized quantitative electron-probe microanalysis was applied for compositional characterization of a ferroelectric ceramic single crystal that was made from the complex perovskite-type solid-solution (1-x)Pb(Mg1/3Nb2/3)O3×xPbTiO3 (PMNT). Cation concentrations were determined with high accuracy and ultimate relative experimental uncertainty of ≤±...
Article
Ultrafine titanium dioxide powder (UF-TiO2) has many applications as a result of its nanometer particle size and semiconducting electric properties. An upgraded method for synthesis of UF-TiO2 was developed, with the ability to control the characteristics of the nanoparticles, i.e. their size, shape and crystal structure. In order to determine the...
Article
The urothelium forms the blood-urine barrier, which depends on the complex organization of transmembrane proteins, uroplakins, in the apical plasma membrane of umbrella cells. Uroplakins compose 16 nm intramembrane particles, which are assembled into urothelial plaques. Here we present an integrated survey on the molecular ultrastructure of urothel...
Article
itanium dioxide (TiO2) rutile nanoparticles were synthesized at temperatures below 100 °C using a gel-sol process that provides control of the final particles' characteristics, such as the nanoparticle size, morphology, crystal structure and crystallinity. The synthesized rutile nanoparticles were analyzed using X-ray powder diffraction (XRD), scan...
Data
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Fe–Pd nanowires were synthesised in anodic alumina templates by applying both potentiostatic and pulsed electrodeposition regimes. When using potentiostatic deposition, only fragmented nanowireswere obtained; however, the use of pulse deposition was shown to be effective for producing solid nanowires. In order to achieve this, different on-times fo...
Article
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Fe-Pd thin films with various compositions and thicknesses were produced with electrodeposition using the constant potentials from -1.0 to -1.3 V. The FEGSEM and AFM analyses revealed a smooth, nanostructured surface morphology of the films, with more granular features appearing at more negative potentials. The high-resolution FEGSEM images of the...
Article
We report on the thermionic field emission and charge transport properties of gold nitride nanodomains grown by pulsed laser deposition with a molecular fluorine laser at 157 nm. The nanodomains are sandwiched between the metallic tip of a conductive atomic force microscope and a thin gold layer forming thus a metal-semiconductor-metal junction. Al...
Article
Flat panel display technology seems to be an ever-expanding field developing into a multibillion dollar market. A set of technical solutions involve a transparent conducting film (TCF) that is today still dominated by indium-tin-oxide (ITO). In a race to find alternatives that would avoid the indium pitfalls, mainly due to its increasing price and...
Article
Anisotropic sintered magnets based on the Nd2Fe14B phase doped with Tb were prepared using a grain-boundary diffusion process (GBDP) in order to enhance their coercivity. A FEGSEM microstructural analysis revealed that these GBDP magnets had a core-shell structure, where thin, Tb-rich, (NdTb)2Fe14B shells are formed on the original matrix Nd2Fe14B...
Article
Copper sulfide (CuS)-based thin films with different thickness have been prepared by thermal co-evaporation of the elemental constituents. Morphological and microstructural properties were shown to vary with film thickness. Optical properties of films encapsulated in a double-glazed configuration and containing an air gap have been measured. Encaps...
Article
We have measured the elemental concentrations in aerosols with a 2-h time resolution in two different types of working environment: a chemistry laboratory dealing with the processing of advanced nanoparticulate materials and a medium-sized machine workshop. Non-stop 10-day and 12-day samplings were performed at each location in order to determine t...
Article
We summarise the X-ray electron spectroscopy (XPS) study of changing surface composition of polycrystalline Ag–2.2 mass% Cu and Ag–5.1 mass% Cu alloys during in situ annealing at chosen temperatures ranging from 300 to 600 °C. The results show obvious surface enrichment by copper, which is different for individual alloys. The contradiction of this...
Article
Near-equiatomic Co–Pt thin films with thicknesses of 520nm were deposited from a single electrolyte onto glass-based Au-coated substrates using the electrodeposition method. The as-deposited Co–Pt-based films were annealed at temperatures from 500ºC to 700ºC for 1h. The phase formation, microstructure and the magnetic properties were analyzed. It w...
Article
Quantitative electron-probe microanalysis (EPMA) with energy-dispersive (EDS) and wavelength-dispersive (WDS) X-ray spectroscopy was performed to determine the chemical composition of Co–Pt ferromagnetic thin films. The conventional “bulk” EPMA approach was applied and tested in detail by using several analytical set-ups with different combinations...
Article
Co–Pt-based tubular nanostructures were prepared by direct plating into track-etched polycarbonate templates from a single electrolyte containing a Pt-p-salt and Co-sulphamate. These tubular nanostructures, with a diameter of 200nm and lengths up to 5μm, were obtained with potentiostatic depositions at potentials of −1.9V to −2.5V, measured against...
Article
The high-temperature behaviour of K0.5Bi0.5TiO3, prepared using a conventional solid-state reaction method, was investigated using X-ray powder diffraction, scanning electron microscopy, wavelength-dispersive X-ray spectroscopy and Knudsen effusion combined with mass spectrometry. The results revealed the formation of an off-stoichiometric matrix p...
Article
X-ray photoelectron spectroscopy was applied to study the evolution of surface composition in a polycrystalline Ag-5.1Cu mass% alloy during in-situ annealing in ultra-high vacuum at temperatures ranging between 300 degrees C and 600 degrees C. The results show an enrichment of copper on the free surface. The results imply that the compositional cha...
Article
An antimicrobial finishing for cotton fabric was prepared from commercial (iSys AG, Germany) silver chloride (Ag) dispersed at different concentrations in a reactive organic–inorganic binder (RB) (iSys MTX (CHT, Germany). Pad-dry-cure and exhaustion methods were used for the sols application, giving Ag-RB coating with Ag concentration from ca. 48 t...
Article
Sm–Fe–Ta–N core-shell (CS) nanospheroids were fabricated from hot liquefied nanodroplets by 157 nm pulse laser deposition in nitrogen gas. The Sm13.8Fe82.2Ta4.0 intermetallic alloy was used as the target. At low laser energy (20 mJ), spherical CS of 1–35 nm radius were fabricated on a Si/Ta substrate forming uniform films. The small nanodroplets we...
Article
Continuous SiC fibers are one of the high-strength fibers [1] that can be used for reinforcing a ceramic matrix composite. In our case this is in a SiC/SiC composite material. Because of its excellent mechanical properties, low induced radioactivity after neutron irradiation, high strength, its specific thermal conductivity and low porosity it can...
Article
Co-Pt alloys have attracted a lot of interest from the applied-magnetism community because of their versatile magnetic properties and good corrosion resistance, which fit in a wide range of potential applications, such as magneto-optical recording, perpendicular magneto-recording, hard magnetic components and, most recently, in MEMS. Co-Pt thin fi...
Article
The microstructure, composition and homogeneity of a Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMNT) single crystal were studied using a combination of electron-microprobe techniques: scanning electron microscopy, orientation analysis and quantitative X-ray microanalysis. A PMNT single crystal was grown from a polycrystalline PMNT matrix using a BaTiO3 single cryst...
Article
The solid solubility of Ho3+ in BaTiO3 fired under the reducing conditions of a nitrogen atmosphere containing 10% of hydrogen was studied by quantitative electron-probe microanalysis using wavelength-dispersive spectroscopy. The solubility was found to depend mainly on the starting composition. In the TiO2-rich samples, the solubility of the Ho3+...
Article
PLZT 5/30/70 sols for thin film deposition have been prepared from lead oxide, lanthanum nitrate and transition metal n-butoxides in a series of etheralcohols. After the low temperature heat treatment at 200 degreesC for 2 minutes and at 400 degreesC for 5 minutes the PLZT 5/30/70 thin films crystallize in the perovskite phase and exhibit ferroelec...
Article
Digital image analysis and point-pattern analysis were applied to the microstructures of Al2O3-ZrO2 composites in order to evaluate and classify the distribution of ZrO2 particles. Scanning electron microscopy micrographs of Al2O3-ZrO2 microstructures were digitized and processed into binary images. Point-pattern analysis was performed using data f...
Article
Ultra-thin films of a few nanometers thick of the DNA bases adenine, guanine and cytosine were prepared on Si substrates by applying laser ablation at 157 nm to etch initially prepared crystal samples from solutions. This was possible because only photochemical dissociation is taking place on DNA bases following illumination with laser light at 157...
Article
Full-text available
The effects of TEA CO2 laser radiation on AISI 420 stainless steel and formed surface structures are studied. The laser energy density of 45.0 J/cm2 has modified the target surface. Qualitatively, the modifications of AISI 420 steel can be summarized as follows: change of color after action of one laser pulse; central zone of interaction in crater...
Article
Incorporation of La3+ into the BaTiO3 lattice was studied on samples of various composition, using quantitative WDS microanalysis (EPMA) in combination with scanning electron microscopy (SEM) and X-ray powder diffractometry (XRPD). Direct determination of solid-solution formulas by microanalysis supports the structure model of a solid solution with...
Article
Sm-Fe thin films were deposited on a Si wafer coated with a similar to 100 nm thick layer of Ta by ablating a solid Sm-Fe target. The Sm-Fe target was ablated using a molecular fluorine laser with lambda = 157 nm at low laser energy of similar to 25 mJ/pulse. The thickness of the deposited amorphous film (in vacuum) was similar to 20 nm and the dim...
Article
The solid solubility of R ions (R = Ho3+, Dy3+, and Y3+) in the BaTiO3 perovskite structure was studied by quantitative electron-probe microanalysis (EPMA) using wavelength-dispersive spectroscopy (WDS), scanning electron microscopy (SEM), and X-ray diffractometry (XRD). Highly doped BaTiO3 samples were prepared using mixed-oxide technology includi...
Article
Incorporation of Nd into the BaCeO3 perovskite structure was studied by quantitative wavelength dispersive spectroscopy-electron probe microanalysis (WDS/EPMA) in combination with scanning electron microscopy (SEM) and X-ray powder diffractometry (XRPD). Highly Nd-doped BaCeO3 specimens, synthesized by mixed oxide technology, were sintered at 1400°...
Article
The solid solubility of the aliovalent dopants Fe3+ and Nb5+ in the BaBi4Ti4O15 compound, a member of the family of Aurivillius bismuth-based layer-structure perovskites, has been studied using quantitative wavelength-dispersive spectroscopic microanalysis (SEM/EPMA) in combination with X-ray powder diffractometry (XRPD). The samples with nominal (...
Article
Full-text available
Laser cleaning of historic paper infected by foxing is far more effective at 157 nm than in other laser wavelengths because at 157 nm localized photo-dissociation of organic matter is taking place at low laser energy. In addition spatial control over exposed areas with resolution better than 100 nm is possible at this wavelength. In order to optimi...
Article
In order to access the damaging mechanisms of DNA and its bases on the molecular level by T Hz radiation, it is necessary to create a database of assessing damage at different spectral regions. Possible damage by T Hz radiation will be assessed by comparison. Furthermore, the expose of the cytosine to radiation at 157 nm, suggest that photochemical...
Article
Using a molecular ¯uorine laser at 157 nm foxing stains were removed successfully from a 16th century old paper. Laser cleaning of stains and foxing from old paper manuscripts is far more effective at 157 nm in comparison to different wavelengths without leaving any yellowish after-effect on the paper. This is because at 157 nm illumination of old...
Article
Quantified wavelength dispersive spectroscopy (WDS) x-ray element maps were used to characterize active (Pb,La)(Ti,Zr)O3 (PLZT) layers on Pt/PLZT/Al2O3 substrates, one fired at 1050 °C and the other at 1150 °C. In the layer fired at 1050 °C, randomly distributed micrometer-sized compositional irregularities were observed as La-rich regions that wer...
Article
The development of microstructural and electrical characteristics (sheet resistivities, TCRs, and noise indices) in some thick-film resistors during the firing process has been evaluated. Three 1 kohm/sq. resistor pastes (Du Pont), based on RuO2, ruthenate or a mixture of both conductive phases, were fired at temperatures from 500C to 950C. The cel...
Article
. Quantitative electron-probe microanalysis was used to determine the chemical composition of an Fe- and Nb-doped bismuth-based BaBi4Ti4O15 perovskite compound. Elemental concentrations of Fe, Nb, Bi, Ba and Ti were accurately measured using wavelength-dispersive X-ray spectroscopy that was optimised for the analysis of a complex oxide matrix conta...
Article
Some 10 kohm/sq. thick film resistors based on RuO2, ruthenates or a mixture of RuO2 and ruthenates, were evaluated for strain gauge applications. The resistors were fired at different temperatures to estimate the influence of firing temperature on the electrical characteristics. Temperature coefficients of resistivity (TCR), noise indices and gaug...
Article
Lead lanthanum zirconium titanate (PLZT), or (Pb,La)(Zr,Ti)O 3 solid solutions, ferroelectric ceramics are being studied for electro-optical applications, as well as for high-speed electrophoretic printing. Thin films of a related material, lead zirconium titanate, or Pb(Zr,Ti)O 3 solid solutions (PZT), are used for non-volatile memories and actuat...
Article
Some commercial thick film resistors with sheet resistivities from 1 kohm/sq. up to 1 Mohm/sq. were evaluated for strain gauge applications. Temperature coefficients of resistivity, noise indices and gauge factors (GFs) were measured. For the same resistor series GFs and noise indices increase with increasing sheet resistivity. However, both GFs an...
Article
A study was conducted to gain some insight into the changes of characteristics, if the resistor materials is "stabilized". The resistors were fired for 10 min at 850 °C and 3 h at 950 °C. Thick-film resistors with a nominal resistivity of 10 kohm/sq. were evaluated. Gauge factors (GFs) and electrical characteristics were measured.
Conference Paper
Some commercial 10 kΩ/sq. thick-film resistors based on RuO <sub>2</sub>, ruthenates or a mixture of RuO<sub>2</sub> and ruthenates, were evaluated for strain gauge applications. The resistors were fired at different temperatures to determine the influence of firing temperature on the electrical characteristics. The conductive phase in the resistor...
Article
To gain some insight into the characteristics of the "overfired" resistors, 1 kohm/sq. resistors were fired for 6 h at 950°C on alumina ceramics. Resistor series HS-80 and 2000 were used. Results indicate that the resistors of newer 2000 series are more robust.
Article
Interactions between (Pb,La)(Zr,Ti)O3 (PLZT) thin and thick films and silicon or alumina substrates, respectively, were studied. In the case of thin films the lowering of the firing temperature inhibits the formation of secondary phases. For thick films the additional layer of PLZT between the a.umina substrate and the Pt electrode improves adhesio...