Colloidal Processing Research Articles

Bentonite colloids immobilization and release in quartz column and its influence on selenite migration

Immobilization and release of colloids are important for colloids-facilitated migrations, and in the safety assessment of geological disposal for high-level radioactive waste, the association between the immobilization and release process of the bentonite colloids with selenite migration has not been well revealed. In this work, the migration of bentonite colloids under different conditions is evaluated, and the effects of colloids immobilization and release on selenite migration are studied. In addition, the cases of in-migration (colloids are immobilized in the quartz sand, and then selenite migrates through the quartz sand with immobilized colloids) and co-migration (colloids bearing selenite are immobilized in the quartz sand) are investigated. The results show that in the systems containing 3.0 mM Mg2+, the mobility of the colloids is highly hindered and the colloids are immobilized in the quartz sand mainly by straining effect. The immobilization of bentonite colloids affects selenite migration differently according to the immobilization process (in-migration or co-migration). A more significant retardation effect is observed in the co-migration process than in-migration due to the additional inner-sphere complexed selenite in the co-migration. The immobilized colloids can be more easily released by alkaline DI-water (pH 11.0) than acidic one (pH 6.0) as a result of the more negative surface charges of the immobilized bentonite colloids. The average size of the released colloids is larger than the initial colloids at the same pH. Selenite is found to be released ahead of colloids in either in- or co-migration process, and part of selenite is discovered migrating with released colloids in co-migration process. Since colloids immobilization and release would influence radionuclides migration, further research about colloids immobilization and release with broad range of pH and ionic strength in the host rock and its influence on the migration of other radionuclides are needed.

LZS bioactive glass-ceramic scaffolds: Colloidal processing, foam replication technique and mechanical properties to bone tissue engineering

Scaffolds are used in bone replacement because present biocompatibility, three-dimensional structure, and high porosity. However, despite the efforts, there are still significant barriers to the development of reliable, synthetic scaffolds to repair large defects is one of the challenges of regenerative medicine. Therefore, innovative solutions are needed better to meet the requirements of a minimally invasive approach while providing adequate vascularity and strength and mechanical reliability. In this sense, the obtainment of a material that satisfies all these requirements is very important. This work aims to evaluate the mechanical properties of glass-ceramic scaffolds of the LZS (Li2O–ZrO2–SiO2) system produced by the replica method. For this, detailed colloidal processing was carried out to identify the solids content, amount of dispersant, and the binder most suitable to produce scaffolds. Finally, the mechanical reliability of the most suitable composition was evaluated by Weibull statistics. Suspensions containing 47 vol% of LZS relative to glass and 0.2 wt % of dispersant were used. In addition, dispersion times and the amount of binder were adjusted. Scaffolds of bioactive glass-ceramics were obtained at 900 °C, replicating polyurethane foams. Then they were morphologically, structurally, and mechanically characterized. The obtained bioactive glass-ceramic scaffolds presented porosity up to 83%, compressive strengths comparable to those of trabecular bone, up to 1.3 MPa, in addition to pore size >300 μm, desirable to favor biological interests destined to the regeneration and formation of bone tissue, demonstrating the possibility of its use as a material for bone replacement or filling. The Weibull modulus found for the glass-ceramic scaffolds produced is 4.18: within the expected range of mechanical reliability for application in bone regeneration.

Using polystyrene spheres to produce thin, porous interlayers in alumina laminates

AbstractPorous alumina layers were produced by colloidal processing of alumina with the addition of 15, 30, and 45 vol% polystyrene spheres (PS) as pore formers. Alumina laminates were designed with dense layers alternated with porous interlayers using 45 vol% of PS spheres and sintered at 1350°C. The layers’ thickness ranged from 2 to 15 μm, with a random distribution of pores. The higher volume fraction of pores tends to decrease the alumina average grain size, but does not influence the final size of bulk and surface pores. The obtained values of hardness and Young's modulus for the porous interlayer are ∼30% of the values obtained for the dense layer. Vickers indentations suggested that crack propagation can be opposed by the porous interlayers. However, values of mechanical strength, fracture toughness (KIC), and work of fracture presented no relevant difference compared to a monolithic reference. R‐curves presented a slight increase and KIC a decrease due to crack propagation through the porous interlayers. Although no macrodeviations of the crack path were observed in the fractured surfaces, microdeviations were detected in the interlayer regions.

Colloidal Shaping of Transparent Spinel through Slip Casting Using Contamination Free Spinel Moulds

Shaping transparent ceramics through slip casting on plaster of Paris (PoP) moulds offers improved transparency compared to compacted samples due to better homogeneity in colloidal processing. However, the contamination due to CaSO4 originated from the PoP contact is a primary concern. Therefore, it demands the machining of several layers from the cast surface that results in post-green machining defects. To address this concern, a magnesium aluminate (MgAl2O4) spinel mould was fabricated with indigenously synthesized spinel powder with optimum porosity of 45-50% and flexural strength of ∼16 MPa. The fabricated spinel mould was used to demonstrate the casting using water-based spinel slurry. The cast spinel blanks were found contamination free as confirmed by Fourier transform infrared studies. Microstructures of spinel moulds revealed the interconnectivity of the pores obtained by field emission scanning electron microscopy. Specimens cast on spinel and on PoP moulds, after post machining, were sintered (1650°C) and hot isostatically pressed (at 1800°C and 1950 bar) under identical conditions. Casting on spinel moulds demonstrated a contamination free surface of the samples. Its properties are at par with the samples cast on PoP moulds, however, with improved casting rate and minimum rejection.

Вариации показателя крупности амарантовой муки

The quality of baked goods is mainly determined by the baking properties of the processed flour. The size of flour as a factor determining the rate of biochemical and colloidal processes in the dough, the properties of the dough, the quality and yield of bread, is an essential indicator of its baking value. In the techno chemical control of bakery production, the method for determining the size of flour is used as a method for determining the size of its particles and is carried out in accordance with GOST 27560–1987. The essence of the method of sieve analysis of flour is to control the fineness with the separation of the prepared sample into separate fractions, to establish the percentage of waste and passage through a set of sieves in accordance with GOST 4403–1991 and calculation of the average equivalent particle size. The purpose of this work was to analyze the variation in the size of amaranth flour obtained in laboratory and industrial conditions. For the variable attribute of the empirical population - the size of amaranth flour, as a result of the analysis of variations, interval series were constructed to obtain a median value characterizing the weighted average particle size. Sieve analysis of amaranth flour (6 samples) showed that the size of the flour can meet the requirements of GOST 7045–2017 for the content of the residue on a sieve made of silk fabric № 27 and be no more than 2% as for seeded rye flour; the requirement of GOST 7045–2017 for the passage through a sieve made of silk fabric № 38 and be at least 30% as for rye whole flour; the requirement of GOST 26574–2017 for the passage through a sieve of silk fabric № 38 and be at least 35% as for wheat whole flour; the requirement of GOST 26574–2017 for the passage through a sieve made of silk fabric № 38 and be at least 65% as for second grade wheat flour. Variations in the size index of amaranth flour (out of 6 samples) can be arranged in ascending sequence: 173,74 μm < 175,84 μm < 180,31 μm < 193,35 μm < 211,75 μm < 214,32 μm.

Sequential Synthesis Methodology Yielding Well-Defined Porous 75%SrTiO3/25%NiFe2O4 Nanocomposite.

In this research, we reported on the formation of highly porous foam SrTiO3/NiFe2O4 (100−xSTO/xNFO) heterostructure by joint solid-state and sol-gel auto-combustion techniques. The colloidal assembly process is discussed based on the weight ratio x (x = 0, 25, 50, 75, and 100 wt %) of NiFe2O4 in the 100−xSTO/xNFO system. We proposed a mechanism describing the highly porous framework formation involving the self-assembly of SrTiO3 due to the gelation process of the nickel ferrite. We used a series of spectrophotometric techniques, including powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), N2 adsorption isotherms method, UV-visible diffuse reflectance spectra (UV-Vis DRS), vibrating sample magnetometer (VSM), and dielectric measurements, to investigate the structural, morphological, optical, magnetic, and dielectric properties of the synthesized samples. As revealed by FE-SEM analysis and textural characteristics, SrTiO3-NiFe2O4 nanocomposite self-assembled into a porous foam with an internally well-defined porous structure. HRTEM characterization certifies the distinctive crystalline phases obtained and reveals that SrTiO3 and NiFe2O4 nanoparticles were closely connected. The specific magnetization, coercivity, and permittivity values are higher in the 75STO/25NFO heterostructure and do not decrease proportionally to the amount of non-magnetic SrTiO3 present in the composition of samples.

Colloidal Processing of Y0.08Zr0.92O2/La0.80Sr0.20MnO3 Semi-Cells Using a Sr-Doped Lanthanum Manganite Synthesized by a Citrate Route.

In this paper, the interface between yttria stabilized zirconia (Y0.08Zr0.92O2, YSZ) electrolyte and Sr-doped lanthanum manganite (La0.80Sr0.20MnO3, LSM) cathode for solid oxide fuel cells (SOFCs) is studied. For such a purpose, the combination of a suitable synthesis route for obtaining fine powders and simple aqueous colloidal shaping routes is proposed. The synthesis of nanosized particles of La0.80Sr0.20MnO3 by a citrate route and their full characterization, including the colloidal stability and the densification and phase development determined by X-ray diffraction and electron microscopy at different temperatures, is reported. In a second step, YSZ tapes were obtained by aqueous tape casting and used as substrates for the preparation of LSM coatings by dip-coating using aqueous slurries. YSZ tapes were used either in the green state or after a pre-sintering treatment. Co-sintering at 1350 °C led to a sharp interface with excellent adhesion, also achieved when coating pre-sintered tapes. In both cases, the substrates are dense and the coatings are porous, with thicknesses of 85 and 60 μm for green and pre-sintered tapes, respectively. No diffusion of Zr and Y occurs at the LSM layer, but some diffusion of La and Mn towards the YSZ layer takes place.

Direct observation of the deformation behavior of agglomerates in a highly concentrated slurry under startup shear flow

Dispersibility and agglomeration of particles in a highly concentrated slurry are important factors in ceramic colloidal processing. In this study, the particles in a transparent slurry, prepared using silica particles and glycerol solution as a model, and their deflocculation under an applied startup shear flow were directly observed using a confocal laser scanning fluorescent microscope. The dispersibility of the particles was changed using additives and was evaluated by studying the rheology and measuring the interaction force between two particles using a scanning probe microscope. A slurry concentrated with polyacrylic ammonium exhibited a shear-thinning behavior, i.e., the gradual transformation of agglomerates into linear chain-like structures on the application of shear-stress, and weak repulsive forces were observed between the particles. The results of this study can enhance the homogeneity of ceramic colloids, powder compacts, and ceramics.

Droplet Formation by Chemically Fueled Self-Assembly: The Role of Precursor Hydrophobicity

We investigate active droplets that form at the expense of a chemical fuel in aqueous buffer and vanish autonomously. Dynamic light scattering reveals the scattered intensity, the hydrodynamic radius, and the width of the size distribution with high precision as well as high temporal and spatial resolutions. Comparing the resulting time-dependent behavior of the droplet characteristics with the time-dependent concentration of the anhydrides, the roles of the chemical reaction cycle and of colloidal growth processes are elucidated. The droplet sizes and lifetimes depend strongly on the hydrophobicity of the precursor, and the growth rate is found to correlate with the deactivation rate of the product.

Colloidal sol-gel: A powerful low-temperature aqueous synthesis route of nanosized powders and suspensions

The colloidal sol-gel is a well-established method for the synthesis of nanoparticles with high reproducibility, homogeneity and low cost. It is a versatile route which allows synthesising many ceramic materials at the nanometric scale. The process starts with the hydrolysis of the metal precursor and ends with the formation of a colloidal suspension/sol with high stability. The particle size can be easily tuned by synthesis parameters such as temperature, metal precursor-water ratio and/or metal precursor-catalyst ratio. Depending on the applications, the sol can be directly used for the preparation of coatings or it can be dried to be used as powder. In this review, the fundamentals of the colloidal sol-gel process are provided, highlighting the great capacity of this synthesis route. Its use in combination with other synthesis methods and the influence of the parameters controlling the process is presented, together with applications and examples of the synthesised powders.

Bifunctional oxidase-peroxidase inorganic nanozyme catalytic cascade for wastewater remediation

Nanozymes are inorganic nanoparticles with enzyme-like features. Noble metals and metal oxide-based nanomaterials can present enzyme-mimicking behavior mediating catalytic reactions including oxidase-, peroxidase-, catalase-, and superoxide dismutase-like activities with important applications in environmental and biomedical grounds. Thus, in this study, it was designed and developed a novel nanosystem that exploits the oxidase-like (OD) behavior of gold nanoparticles (AuNPs, GOLDzyme) and the peroxidase-like (POD) characteristics of cobalt-doped magnetic iron oxide nanoparticles (MIONs, Co-MIONzyme) amalgamated in an inorganic-inorganic bi-nanozyme cascade for the degradation of dye pollutants. GOLDzyme and Co-MIONzyme nanomaterials were synthesized and stabilized by citrate and carboxymethylcellulose (CMC) ligands, respectively, using a green aqueous colloidal process at mild conditions. The physicochemical characterization results indicated that water-dispersible colloidal supramolecular nanostructures were effectively produced, with core-shell morphologies (i.e., inorganic nanoparticle core/organic-shell). The AuNPs (GOLDzyme) presented crystalline nanostructure, with a uniform spherical shape, zeta potential (ZP) = - 46 ± 3 mV, hydrodynamic diameter (DH) = 11 ± 3 nm. Analogously, the Co-MIONzyme stabilized by CMC ligand evidenced the formation of nanocrystalline substituted magnetite (CoxFe3−xO4) with uniform spherical morphology, average size = 7.0 ± 2 nm, ZP = - 47 ± 3 mV, DH = 46 ± 3 nm, and superparamagnetic behavior. When tested separately using a colorimetric assay based on a chromogenic molecule (3,3′,5,5′ tetramethylbenzidine, TMB), they demonstrated catalytic activity upon the injection of each specific substrate in the medium, i.e., glucose for GOLDzyme that behaved predominantly as oxidase-like nanomaterial, and H2O2 for Co-MIONzyme, which showed a peroxidase-like or catalase-like behavior. In addition, these nanozymes demonstrated pH-dependent and temperature-dependent catalytic activities. As a proof of concept, when combined into a single-pot reaction system, these bifunctional nanozymes confirmed integrated catalytic cascade as oxidase and peroxidase-like nanocatalysts towards the oxidation of TMB and the degradation of methylene blue (MB, ~18%) as the model dye pollutant. Based on the preliminary encouraging results of this research, it can be foreseen that the combination of nanozymes paves the way for the development of new nanoplatforms for prospective applications in water treatment and environmental remediation.

Electrophoretic deposition of carbon-supported octahedral Pt–Ni alloy nanoparticle catalysts for cathode in polymer electrolyte membrane fuel cells

The advanced electrochemical catalytic activity for oxygen reduction reaction (ORR) based on the octahedral Pt–Ni alloyed catalyst has been demonstrated. However, a means of fabricating catalyst electrodes for use in PEMFCs that is cost-effective, scalable, and maintains the high activity of Pt–Nialloy/C has remained out of reach. Electrophoretic deposition (EPD) is a colloidal production process that has a history of successful deployment at the industrial scale. Here, we report on the facile preparation of an effective and active cathode consisting of Pt–Ni alloy loaded on the carbon cloth substrate using the electrophoretic deposition (EPD) technique, in which the optimum applied voltages and suspension pH are systematically investigated to obtain the highly porous Pt–Nialloy/C catalyst electrode. In a half cell test, the EPD-made Pt–Nialloy/C catalyst electrodes fabricated at 45 V and in a solution with a pH of 9.0 yields the best performances. On the other, as an active cathode, the EPD-made Pt–Nialloy/C electrodes deliver a superior performance in single cell test, with the maximum power density reaches 7.16 W/mgPt, ∼28.1% higher than that of the spray-made Pt/C conventional electrode. The outperformance is attributed to the significantly higher porosity and surface roughness of the EPD-made electrode.

Soft-Microstructured Transparent Electrodes for Photonic-Enhanced Flexible Solar Cells

Microstructured transparent conductive oxides (TCOs) have shown great potential as photonic electrodes in photovoltaic (PV) applications, providing both optical and electrical improvements in the solar cells’ performance due to: (1) strong light trapping effects that enhance broadband light absorption in PV material and (2) the reduced sheet resistance of the front illuminated contact. This work developed a method for the fabrication and optimization of wavelength-sized indium zinc oxide (IZO) microstructures, which were soft-patterned on flexible indium tin oxide (ITO)-coated poly(ethylene terephthalate) (PET) substrates via a simple, low-cost, versatile, and highly scalable colloidal lithography process. Using this method, the ITO-coated PET substrates patterned with IZO micro-meshes provided improved transparent electrodes endowed with strong light interaction effects—namely, a pronounced light scattering performance (diffuse transmittance up to ~50%). In addition, the photonic-structured IZO mesh allowed a higher volume of TCO material in the electrode while maintaining the desired transparency, which led to a sheet resistance reduction (by ~30%), thereby providing further electrical benefits due to the improvement of the contact conductance. The results reported herein pave the way for a new class of photonic transparent electrodes endowed with mechanical flexibility that offer strong potential not only as advanced front contacts for thin-film bendable solar cells but also for a much broader range of optoelectronic applications.

Formation of a colloidal band via pH-dependent electrokinetics.

Electroosmosis on nonuniformly charged surfaces often gives rise to intriguing flow behaviors, which can be utilized in applications such as mixing processes and designing micromotors. Here, we demonstrate nonuniform electroosmosis induced by electrochemical reactions. Water electrolysis creates pH gradients near the electrodes that cause a spatiotemporal change in the wall zeta potential, leading to nonuniform electroosmosis. Such nonuniform EOFs induce multiple vortices, which promote the continuous accumulation of particles that subsequently form a colloidal band. The band develops vertically into a "wall" of particles that spans from the bottom to the top surface of the chamber. Such a flow-driven colloidal band can be potentially used in colloidal self-assembly and separation processes irrespective of the particle surface properties. For instance, we demonstrate these vortices can promote rapid segregation of soft colloids such as oil droplets and fatglobules.

Synthesis of novel hexamolybdenum cluster-functionalized copper hydroxide nanocomposites and its catalytic activity for organic molecule degradation

ABSTRACT A novel heterogeneous catalytic nanomaterial based on a molybdenum cluster-based halide (MC) and a single-layered copper hydroxynitrate (CHN) was first prepared by colloidal processing under ambient conditions. The results of the elemental composition and crystalline pattern indicated that CHN was comprehensively synthesized with the support of the MC compound. The absorbing characteristic in the ultraviolet and near-infrared regions was promoted by both of the ingredients. The proper chemical interaction between the materials is a crucial reason to modify the structure of the MCs and only a small decrease in the magnetic susceptibility of CHN. The heterogeneous catalytic activity of the obtained MC@CHN material was found to have a high efficiency and excellent reuse when it is activated by hydrogen peroxide (H2O2) for the degrading reaction of the organic pollutant at room temperature. A reasonable catalytic mechanism was proposed to explain the distinct role of the copper compound, Mo6 compound, and H2O2 in the production of the radical hydroxyl ion. This novel nanomaterial will be an environmentally promising candidate for dye removal.

Two-dimensional colloidal particle assembly in ionic surfactant solutions under an oscillatory electric field

Assembling colloidal particles under oscillatory electric field (OEF) has become an emerging bottom-up technique to synthesize advanced materials and fabricate micro/nano devices. Surfactants have often been used in colloidal dispersions to improve their stability. However, the precise role of surfactants in particle assembly processes under OEF is unknown. Here, we systematically study the effects of ionic surfactants on the colloidal particle assembly process subject to a fixed OEF, by using an anionic surfactant (sodium dodecyl sulfate) and a cationic surfactant (cetyltrimethylammonium bromide). In the concentration range below the critical micelle concentration (CMC), the particles tend to form three different aggregate structures, including randomly close-packed, hexagonally close-packed crystals, and randomly non close-packed structures. In the concentration range at CMC and above, the particles cannot assemble into any aggregate structures under the given OEF. With increasing surfactant concentration, the average interparticle separation distance within the aggregate can be regulated in a wide range. We qualitatively interpret the observed variation of particle assembly behaviors in different surfactant solutions based on the particle/particle interaction energy, implying that the repulsive electric double-layer interaction is significantly enhanced with increasing ionic surfactant concentration and hinders the particles approaching close to the high-energy barrier. These results suggest that the particle aggregate structure and interparticle separation distance of the two-dimensional colloidal assembly can be manipulated by controlling the ionic surfactant concentration according to the requirements of practical applications.

Operational Variables on the Processing of Porous Titanium Bodies by Gelation of Slurries with an Expansive Porogen

Colloidal processing techniques, based on the suspension of powders in a liquid, are very versatile techniques to fabricate porous structures. They can provide customized pores, shapes and surfaces through the control of operational parameters, being the base of the alternative additive manufacture processes. In this work disperse and stable titanium aqueous slurries has been formulated in order to process porous materials by the incorporation of methylcellulose (MC) as a gelation agent and ammonium bicarbonate as an expansive porogen. After casting the slurries and heating at mild temperatures (60–80 °C) the methylcellulose gels and traps the gas bubbles generated by the ammonium bicarbonate decomposition to finally obtain stiff porous green structures. Using an experimental design method, the influence of the temperature as well as the concentration of gelation agent and porogen on the viscosity, apparent density and pore size distribution is analyzed by a second-order polynomial function in order to identifying the influence of the operating variables in the green titanium porous compact. After sintering at 1100 °C under high vacuum, titanium sponges with 39% of open porosity and almost no close porosity were obtained.

Reproducibility and Scalability of Magnetic Nanoheater Synthesis.

The application of magnetic nanoparticles requires large amounts of materials of reproducible quality. This work explores the scaled-up synthesis of multi-core iron oxide nanoparticles through the use of thermal decomposition in organic media and kilograms of reagents. To this end, we check the effect of extending the high temperature step from minutes to hours. To address the intrinsic variability of the colloidal crystallization nucleation process, the experiments were repeated and analyzed statistically. Due to the simultaneity of the nuclei growth and agglomeration steps, the nanostructure of the samples produced was a combination of single- and multi-core nanoparticles. The main characteristics of the materials obtained, as well as the reaction yields, were analyzed and compared. As a general rule, yield, particle size, and reproducibility increase when the time at high temperature is prolonged. The samples obtained were ranked in terms of the reproducibility of different structural, colloidal, and magnetic features. The capability of the obtained materials to act as nanoheaters in magnetic hyperthermia was assessed, showing a strong dependence on the crystallite size (calculated by X-ray diffraction), reflecting the nanoparticle volume with a coherent magnetization reversal.

Microscopic origins of the crystallographically preferred growth in evaporation-induced colloidal crystals

Unlike crystalline atomic and ionic solids, texture development due to crystallographically preferred growth in colloidal crystals is less studied. Here we investigate the underlying mechanisms of the texture evolution in an evaporation-induced colloidal assembly process through experiments, modeling, and theoretical analysis. In this widely used approach to obtain large-area colloidal crystals, the colloidal particles are driven to the meniscus via the evaporation of a solvent or matrix precursor solution where they close-pack to form a face-centered cubic colloidal assembly. Via two-dimensional large-area crystallographic mapping, we show that the initial crystal orientation is dominated by the interaction of particles with the meniscus, resulting in the expected coalignment of the close-packed direction with the local meniscus geometry. By combining with crystal structure analysis at a single-particle level, we further reveal that, at the later stage of self-assembly, however, the colloidal crystal undergoes a gradual rotation facilitated by geometrically necessary dislocations (GNDs) and achieves a large-area uniform crystallographic orientation with the close-packed direction perpendicular to the meniscus and parallel to the growth direction. Classical slip analysis, finite element-based mechanical simulation, computational colloidal assembly modeling, and continuum theory unequivocally show that these GNDs result from the tensile stress field along the meniscus direction due to the constrained shrinkage of the colloidal crystal during drying. The generation of GNDs with specific slip systems within individual grains leads to crystallographic rotation to accommodate the mechanical stress. The mechanistic understanding reported here can be utilized to control crystallographic features of colloidal assemblies, and may provide further insights into crystallographically preferred growth in synthetic, biological, and geological crystals.

Synthesis and processing of improved graphite-molybdenum-titanium composites by colloidal route and spark plasma sintering

Graphite-molybdenum-titanium composites might attract significant interest as heat sinks for different sector applications due to their excellent thermal, electrical and mechanical properties. This type of composites was already studied but following the powder metallurgy and spark plasma sintering (SPS) route. The aim of the present investigation is to study a new route of fabrication of these composites to improve their properties: colloidal synthesis and SPS process. The results obtained for graphite-10 vol% Mo-1 vol% Ti composites prepared by both routes are compared. It has been proved that the properties of the composites are significantly improved by the colloidal route compared with the powder metallurgy route, i. e. electrical conductivity by a factor of 3, thermal properties by a factor of 8 and bending strength by a factor of 4.