Catalytic upgrading of biomass fast pyrolysis vapors with titania and zirconia/titania based catalysts

Fast pyrolysis of poplar wood followed with catalytic upgrading of the pyrolysis vapors was performed using analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The catalysts applied in this study were three commercial meso- or macroporous catalysts (TiO₂ (Rutile), TiO₂ (Anatase) and ZrO₂&TiO₂) and their modified ones with incorporation of Ce, Ru or Pd. These catalysts displayed different catalytic effects on the pyrolytic products. The TiO₂ (Rutile) based catalysts, especially the Pd/CeTiO₂ (Rutile), were effective to convert the lignin-derived oligomers to monomeric phenolic compounds, with the phenols increasing from 25.6% in the non-catalytic products to 37.2% after catalyzed by the Pd/CeTiO₂ (Rutile). The ZrO₂&TiO₂ based catalysts were the most effective to change the pyrolytic products. They significantly reduced the phenols, acids and sugars, and meanwhile, increased the hydrocarbons, linear ketones and cyclopentanones. The highest hydrocarbon content of 13.1% was obtained by the ZrO₂&TiO₂, compared with only 0.1% in the non-catalytic products. The catalytic effects of the TiO₂ (Anatase) based catalysts were between that of the TiO₂ (Rutile) and ZrO₂&TiO₂ based catalysts.     

Comparative Assessment of Crystallographic Phase Stability of Anatase and Rutile TiO2 at Dynamic Shock Wave Loaded Conditions

In the present research article, authors have experimentally evaluated the shock wave resistant properties of technologically potential materials of the anatase and the rutile phase TiO₂ nanoparticles at the dynamic shock wave loaded conditions. The shock wave resistant behavior has been quantitatively drawn utilizing the crystallographic phase stability of the test samples for which the required crystallographic information has been extracted from the powder XRD patterns. Based on our observed experimental results as well as the respective interpretations, it is strongly authenticated that Rutile TiO₂ NPs are suitable candidates for aerospace and defense industrial applications of materials fabrications because of the outstanding shock resistant properties than that of Anatase TiO₂ NPs which undergo the crystallographic phase transition of rutile-TiO₂ at shocked conditions.

     

Functionalizing slag wool fibers with photocatalytic activity by anatase TiO2 and CTAB modification

Anatase TiO₂ coatings prepared by solvothermal process in a neutral ethanol solution of isopropyl titanate at 160 °C have been grown on slag wool fibers (SWF) which were modified by hexadecyltrimethylammonium bromide (CTAB) in advance. X-ray diffraction patterns confirmed the coatings are of a nanocrystalline anatase structure, and scanning electron microscopy observations and energy-dispersive X-ray spectrum revealed a continuous coverage of TiO₂ formed on the fiber surfaces. The photocatalytic activity of the samples was tested by the photocatalytic degradation of methylene blue (MB) solution. The results show that CTAB modified slag wool fibers (CMSWF) are not a suitable adsorbent for MB due to their weaker negative surface charges. Anatase TiO₂ coated CMSWF display higher photocatalyst activity than anatase TiO₂ coated SWF without CTAB modification, and Anatase TiO₂ coated CMSWF are relatively stable under UV-light irradiation.     

Nanocrystalline TiO2 on single walled carbon nanotube arrays: Towards the assembly of organized C/TiO2 nanosystems

Arrays of single walled carbon nanotube bundles organized following different architectures have been coated by a homogeneous deposit of nanocrystalline titania. The nanotubes were grown treating nanosized C powders with atomic H in a purpose-designed chemical vapor deposition (CVD) reactor, the subsequent TiO₂ deposition was performed at 400 °C using the metal-organic CVD (MOCVD) technique and titanium tetraisopropoxide Ti(OⁱPr)₄ as a precursor. X-ray diffraction and Raman spectroscopy evidence the anatase structure of the TiO₂ coatings, formed by grains with an average size of about 55 nm. The structural and compositional characteristics of the TiO₂ deposits are not sensitive to the organization of the nanotube arrays, which maintain their pristine architectures. The adopted synthetic procedure opens a new route for the immobilization of anatase-type TiO₂ nanocrystallites onto geometrically varied structures and for the integration of composite nanotube/TiO₂ systems in effective devices.     

The role of the diluent phase in the mechanochemical preparation of TiO2 nanoparticles

Anatase and rutile TiO₂ nanoparticles were synthesized via mechanochemical reaction and subsequent annealing of the products. TiO₂ nanoparticles were prepared by the use of planetary ball milling of titanyl sulphate (TiOSO₄.xH₂O.yH₂SO₄) and NaCl powders as the reactant and diluent phases, respectively. In this paper, the effect of volume fraction of diluent phase (NaCl) on the particle size distribution and agglomeration of TiO₂ nanoparticles is studied. Final products were obtained by annealing the milled powders at 700 °C for half an hour and subsequent washing out the water-soluble NaCl. X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) investigations showed that the increase in NaCl:TiOSO₄ weight ratio (NTR) leads to the formation of nanocrystalline anatase and rutile particles with more uniform size distribution, lower weight ratio of rutile phase and lower agglomeration of particles.     

Multifunctional ZnO/TiO2 nanoarray composite coating with antibacterial activity,cytocompatibility and piezoelectricity

Metal oxides with nanostructures such as zinc oxide (ZnO), titanium dioxide (TiO₂) have been used in biomedical fields for their multifunctional properties. In this study, ZnO/TiO₂ nanoarray (nZnO/TiO₂) coatings were prepared via hydrothermal synthesis followed by low temperature liquid phase method. The particle size of the composites were no more than 100 nm in diameter, assembled into nanoarray on the Ti substrate. In vitro antibacterial experiments showed that the maximum bacteriostatic rate could reach 99% against Staphylococcus aureus and 90% against Escherichia coli, respectively. Moreover, the nZnO/TiO₂ coatings were of cytocompatibility and biocompatibility, promoting the proliferation of MC3T3-E1 and the expression of alkaline phosphatase (ALP). The piezoelectric properties of nZnO/TiO₂ coatings were preliminarily investigated. The smaller the size of the composite particle was, the better the antibacterial property, biocompatibility and piezoelectric properties were. Under the stimulation of the periodic loading, the growth of MC3T3-E1 was promoted, so the secretion of ALP was. The nZnO/TiO₂ composite coating with antibacterial activity, osteogenesis and intellectual stimulation would be a promising smart coating for orthopedic implants.     

Electrochemical lithium insertion into anatase-type TiO2: An in situ Raman microscopy investigation

Anatase type TiO₂ has been previously largely reported as a candidate negative electrode material for lithium-ion batteries. We report here for the first time the complete in situ Raman study of lithium insertion and de-insertion into three variously nano-sized TiO₂ anatase powders (Prolabo, ca. 80 nm, AK1, ca. 15 nm and MTi5 ca. 8 nm), of which AK1 and MTi5 show superior capacity and cyclability. From these measurements realized in a galvanostatic mode between 3 and 1 V versus Li/Li⁺, the phase transition from a tetragonal to an orthorhombic structure was clearly observed to take place at different quantities of x in Li_xTiO₂. These results confirm the extension of the solid solution domain as particle size is reduced. For the smaller TiO₂ nano-sized materials (AK1 and MTi5), a more pronounced decrease in band intensity when x > 0.3 for Li_xTiO₂, was observed and may be related to the decrease in the optical skin depth linked to the conductivity increase as lithiation proceeds.     

Correlation between microstructure and properties of biocomposite coatings

A SiO₂–CaO–Na₂O (SCN) based bioactive glass was used to prepare glass–matrix/Ti particle composite coatings (SCNT). The coatings were obtained by vacuum plasma spray (VPS) on Ti–6Al–4V substrates. Two different deposition methods have been compared: (a) VPS of powders obtained by ball milling of sintered composites; (b) in situ plasma spray of mixed titanium and glass powders. For comparative purposes, pure SCN glass coatings were produced. The coating morphology and microstructure were observed by optical and scanning electron microscopy, compositional analyses by energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). Comparative mechanical tests were carried out by shear tests and by Vickers indentations at the interface between the substrate and the coatings. The bioactivity of glass- and composite coatings was investigated in vitro by soaking them in a simulated body fluid (SBF) with the same ion concentration of the human plasma. All the layers retain their starting composition. The composite coatings obtained by VPS of the powdered presintered composites showed a better mechanical behaviour with respect both to the composite coatings obtained by the in situ method and to the pure glass coatings. Both the glass- and the two kind of composite coatings revealed to be bioactive by the growth of a thick apatite layer after 30 days of soaking in SBF. The electrochemical behaviour of the SCNT coatings was evaluated by means of potentiodynamic anodic polarization curves and free corrosion potential measurements in Ringer solution at 25 °C. For comparative purposes the same analyses were performed on analogous bioactive glass-matrix/Ti particle composite coated samples, based on the system TiO₂–SiO₂–CaO–B₂O₃ (TSCB), and obtained both by the in situ and by presintering method as well. The results of the electrochemical tests showed a better corrosion behaviour of the samples coated by VPS of powdered sintered composites with respect to those coated by in situ VPS composites.     

Possibilities of the Computer-Controlled Detonation Spraying method: A chemistry viewpoint

This article is aimed to discuss the chemical aspects of detonation spraying of powder materials. In this method of coating deposition, ceramic, metallic or composite powders are injected into the barrel of a detonation gun filled with an explosive gaseous mixture. When the latter is ignited, the powders are heated and accelerated toward the substrate. Subjected to high temperatures, the powders are prone to chemical reactions, the reaction products possibly becoming the major phase constituents of the coatings. What types of reactions are possible? Can these reactions be carried out in a controlled manner? We answer these questions considering the interactions of the sprayed powders with the gaseous environment of the barrel as well as those between the phases of a composite feedstock powder. In Computer-Controlled Detonation Spraying (CCDS), the explosive charge and stoichiometry of the fuel-oxygen mixtures are precisely measured and can be flexibly changed. Our studies demonstrate that with the introduction of a highly flexible process of CCDS, detonation spraying has entered a new development stage, at which it can be considered as a powerful method of composition and microstructure tailoring of thermally sprayed coatings. During CCDS of TiO₂-containing powders, chemical reduction of titanium dioxide can be carried out to different levels to form either oxygen-deficient TiO_2−x or Ti₃O₅ suboxide. CCDS of Ti₃Al can produce titanium oxide coatings when oxidation by the detonation products dominates or titanium nitride-titanium aluminide coatings when oxidation is hindered but the interaction of the powders with nitrogen—a carrier gas component—is favored. During detonation spraying of Ti₃SiC₂–Cu composites, the Ti₃SiC₂ phase is preserved only in cold conditions; otherwise, Si de-intercalates from the Ti₃SiC₂ phase and dissolves in Cu resulting in the formation of the TiC_x–Cu(Si) composite coatings.     

Vacuum thermal treated electroless NiP-TiO2 composite coatings

Composite NiP-TiO₂ layers were prepared by simultaneous electroless deposition of Ni-P and TiO₂ on steel substrate, from a solution in which TiO₂ particles were kept in suspension by stirring. Deposits were characterized for its structure, morphology and hardness. It was found that the chemical composition of Ni-P matrix has been influenced by the incorporation of TiO₂ particles. TiO₂ particle incorporation increases with increase in their bath concentrations (0.5-2.0 g/l). An improvement (up to 20%) in microhardness was observed in both as plated and vacuum heat-treated composite coatings compared to Ni-P coatings. Electroless deposited composite coatings exhibit an amorphous structure of the nickel matrix in which crystalline titanium oxide is incorporated. Vacuum heat treatment leads to the formation of a crystalline layer in which the Ni and Ni₃P crystallites appear apart from those of the TiO₂ (anatase). Potentiodynamic polarization measurements made on these deposits in 3.5 wt.% sodium chloride solution showed decrease in the corrosion resistance for the as-plated and heat-treated composite coatings.     

Study on the formation process of Al2O3-TiO2 composite powders

Fine particles of anatase were suspended in solutions of ammonium alum with Al₂O₃/TiO₂ molar ratios from 0.1:1 to 7:1. By spray drying the suspensions and calcining the spray-dried powders, Al₂O₃-TiO₂ composite particles were obtained. The results show that after the spray drying, coatings of ammomium alum are formed on the surface of the anatase particles, leading to composite precursor powders (CCPs) with larger particle sizes. Upon calcining the CCPs, ammomium alum pyrolyzes to amorphous Al₂O₃ and anatase transforms into rutile. Both are mainly responsible for the observed particle size reductions as well as the densification of each composite particle. The in-situ formed α-Al₂O₃ and rutile may have higher reactivities, forming aluminum titanate at 1150 °C, about 130 °C lower than the theoretical temperature for the formation of Al₂TiO₅ by solid reaction. The reaction between α-Al₂O₃ and rutile starts from the interface between the anatase and the alum coating and mainly takes place in the single particles formed by spray drying. The molar ratio of Al₂O₃ to TiO₂ influences the final crystalline phases in the composite powders, but not stoichiometrically.     

Effect of titania particles preparation on the properties of Ni–TiO2 electrodeposited composite coatings

In this paper, the effect of titania particles preparation on the properties of Ni–TiO₂ electrocomposite coatings has been addressed. Titania particles were prepared by precipitation method using titanium tetrachloride as the precursor. The titanyl hydroxide precipitate was subjected to two different calcinations temperatures (400 and 900 °C) to obtain anatase and rutile titania particles. These particles along with commercial anatase titania particles were separately dispersed in nickel sulfamate bath and electrodeposited under identical electroplating conditions to obtain composite coatings. The electrodeposited coatings were evaluated for their microhardness, wettability, corrosion resistance, and tribological behavior. The variation of microhardness with current density exhibited a similar trend for all the three composite coatings. The composite coating containing anatase titania particles exhibited higher microhardness and improved wear resistance. However, the corrosion resistance of the composite coating containing commercial titania powder was superior to that of plain nickel, Ni–TiO₂ composite coatings containing anatase and rutile titania particles. The poor corrosion resistance of these composite coatings was attributed to the higher surface roughness of the coatings. This problem was alleviated by incorporating ball-milled titania powders. The composite coatings with higher surface roughness were modified with a low surface energy material like fluoroalkyl silane to impart hydrophobic and superhydrophobic properties to the coatings. Among these coatings, Ni–TiO₂–9C coating exhibited the highest water contact angle of 157°.     

Enhancement of UV-aging resistance of UV-curable polyurethane acrylate coatings via incorporation of hindered amine light stabilizers-functionalized TiO<Subscript>2</Subscript>-SiO<Subscript>2</Subscript> nanoparticles

In this study, polymeric hindered amine light stabilizers (HALS)-functionalized silica coated rutile titanium dioxide (TiO₂-SiO₂) nanoparticles were prepared by encapsulating commercially available TiO₂-SiO₂ nanoparticles with methyl methacrylate (MMA) and 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate (PMPM) copolymers via miniemulsion polymerization. The obtained functional (TiO₂-SiO₂/P(MMA-co-PMPM)) fillers have been added to polyurethane acrylate (PUA) oligomers to get UV-curable nanocomposite coatings. The functionalization of the TiO₂-SiO₂ nanoparticles with polymeric HALS has been confirmed by infrared spectra (IR), thermogravimetric (TG), and X-ray photoelectron spectroscopy (XPS) analyses. The scanning electron microscope (SEM) micrographs indicated that homogeneous dispersion of TiO₂-SiO₂/P(MMA-co-PMPM) composite nanoparticles resulted in improved transparency and mechanical properties of the UV-curable PUA coatings. Rhodamine B (Rh.B) photodegradation measurement confirmed the excellent UV-shielding performance of PUA nanocomposite coatings containing TiO₂-SiO₂/P(MMA-co-PMPM). The addition of TiO₂-SiO₂/P(MMA-co-PMPM) composite nanoparticles reduced the UV-curable PUA coatings degradation rate dramatically. The UV-aging resistance of PUA coatings was improved significantly. Over all, the combination of TiO₂-SiO₂ nanoparticles and polymeric HALS offers an attractive way to fabricate the multi-functional fillers, which can be used to improve the mechanical properties and UV-aging resistance of PUA coatings simultaneously.     

Bioactive HA/TiO2 coating on magnesium alloy for biomedical applications

Magnesium alloys are new class of biodegradable alloys having many favourable properties to overcome the limitations of currently used biomedical alloys. Recently, several coatings have been developed to overcome their higher degradation rate. In this regard, a new attempt has been made to develop Hydroxyapatite and Hydroxyapatite/TiO₂ coatings on magnesium alloys to increase the biocompatibility and reduce the corrosion rate. The coated surfaces were characterized by Fourier-Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction Analysis (XRD), Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray (EDX) Spectroscopy, Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM). Contact angle measurements proved higher hydrophilic nature of HA/TiO₂ coating compared to HA coating. In-vitro studies showed that HA–TiO₂ coated alloy exhibited higher osteoinduction compared to HA coated alloy. Hydrogen evolution studies and corrosion studies confirmed greater reduction in degradation rate of HA/TiO₂ coated alloy. Vickers microhardness test also showed enhancement in mechanical strength of the composite coated alloy compared to HA coated alloy. Three point bend test depicted better adherence of the HA/TiO₂ coating compared to HA coating on the substrate. Cell culture studies proved higher cell attachment and proliferation on composite coated alloy by controlling the release of magnesium ions into the surrounding body tissue.     

Optimization of sulfamethoxazole degradation by TiO2/hydroxyapatite composite under ultraviolet irradiation using response surface methodology

A titanium dioxide/hydroxyapatite/ultraviolet (TiO₂/HAP/UV-A) system was used to remove sulfamethoxazole (SMX) from water in a second-order response surface methodology (RSM) experiment with a three-level Box-Behnken design (BBD) for optimization. The effects of both the primary and secondary interaction effects of three photocatalytic reaction variables were examined: the concentration of SMX (X₁), dose of TiO₂/HAP composite (X₂), and UV intensity (X₃). The UV intensity and TiO₂/HAP dose significantly influence the SMX and total organic carbon (TOC) removal (p<0.001). However, the SMX and TOC removal are enhanced with increasing TiO₂/HAP dose up to certain levels, and further increases in the TiO₂/HAP dose result in adverse effects due to hydroxyl radical scavenging at higher catalyst concentrations. Complete removal of SMX was achieved upon UV-A irradiation for 180min. Under optimal conditions, 51.2% of the TOC was removed, indicating the formation of intermediate products during SMX degradation. The optimal ratio of SMX (mg L^?1) to TiO₂/HAP (g L^?1) to UV (W/L) was 5.4145 mg L^?1 to 1.4351 g L^?1 to 18W for both SMX and TOC removal. By comparison with actual applications, the experimental results were found to be in good agreement with the model’s predictions, with mean results for SMX and TOC removal of 99.89% and 51.01%, respectively.     

Sol-gel synthesis,spark plasma sintering,structural characterization,and thermal conductivity measurement of heavily Nb-doped SrTiO3/TiO2 nanocomposites

Heavily Nb-doped strontium titanate (SrTi_1-xNb_xO₃) nanoparticles and SrTi_1-xNb_xO₃/TiO₂ nanocomposite powders were synthesized by a sol-gel method. Structural characterization of the obtained powders was performed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and UV–visible spectroscopy. The powders were densified by spark plasma sintering (SPS) method up to 98% of the relative density. Upon composite production, the thermal conductivity of the un-doped samples was effectively decreased for SrTiO₃/TiO₂ nanocpmposite from 12 to 8 W/m.K. On the other hand, thermal conductivity of the Nb-doped SrTi_0.8Nb_0.2O₃/TiO₂ composite was decreased by about 50% down to 3.4 W/m.K in comparison to SrTiO₃/TiO₂ due to the phonon scattering at the point defects originated from both Nb atoms and TiO₂ nanoparticles.     

A novel hybrid composite coating of poly-3-amino-5-mercapto-1,2,4-triazole/TiO<Subscript>2</Subscript> on copper for corrosion protection

Poly-3-amino-5-mercapto-1,2,4-triazole/TiO₂ (p-AMTA/TiO₂) composite was effectively synthesized over the copper surface by cyclic voltammetric technique and used as a protective coating against corrosion. The resulting polymeric composite was characterized using Fourier transform infrared spectroscopy. The presence of TiO₂ particles in the polymer matrix was substantiated from X-ray diffraction pattern and energy-dispersive X-ray spectrum. The uniform dispersion of TiO₂ particles in the polymeric matrix was confirmed by the scanning electron microscope images. The protective effect of composite coating was evaluated by electrochemical impedance spectroscopy and potentiodynamic polarization methods in 3.5 % NaCl medium. Impedance measurements showed that charge transfer resistance (R _ct) values increased for polymeric composites which suggested the enhanced corrosion protection of copper. Further, the decrease in corrosion current density (i _corr) values and shifting of corrosion potential (E_corr) toward the cathodic direction confirmed the anticorrosive behavior of the polymeric composite. The reason for the higher protection of polymeric composite may be due to the well-dispersed TiO₂ particles in the polymer matrix exhibiting the enhanced barrier properties to protect copper surface from corrosion. The defects in the coatings can be reduced by embedded TiO₂ particles in the pores of the polymeric films to enhance the corrosion protection, consequently.     

Sintering of Al2O3-SiC composite from sol-gel method with MgO, TiO2 and Y2O3 addition

Al₂O₃-SiC composite ceramics were prepared by pressureless sintering with and without the addition of MgO, TiO₂ and Y₂O₃ as sintering aids. The effects of these compositional variables on final density and hardness were investigated. In the present article at first α-Al₂O₃ and β-SiC nano powders have been synthesized by sol-gel method separately by using AlCl₃, TEOS and saccharose as precursors. Pressureless sintering was carried out in nitrogen atmosphere at 1600 °C and 1630 °C. The addition of 5 vol.% SiC to Al₂O₃ hindered densification. In contrast, the addition of nano MgO and nano TiO₂ to Al₂O₃-5 vol.% SiC composites improved densification but Y₂O₃ did not have positive effect on sintering. Maximum density (97%) was achieved at 1630 °C. Vickers hardness was 17.7 GPa after sintering at 1630 °C. SEM revealed that the SiC particles were well distributed throughout the composite microstructures. The precursors and the resultant powders were characterized by XRD, STA and SEM.     

Development of a novel smart carrier for drug delivery: Ciprofloxacin loaded vaterite/reduced graphene oxide/PCL composite coating on TiO2 nanotube coated titanium

In the field of orthopaedic implants, post-surgery infections and biocompatibility are the most challenging obstacles. Sustained and controlled antibiotic release is a key factor in novel drug delivery systems. A novel drug delivery system combined with vaterite microsphere, graphite oxide (GO), reduced graphene oxide (rGO) incorporated in a polycaprolactone (PCL) matrix on TiO₂ nanotube coated Ti (TNT-Ti) is established. Anodization was employed to develop TiO₂ nanotubular arrays on Ti. Ciprofloxacin hydrochloride (CPF–HCl) loaded vaterite microspheres were synthesized by in situ precipitation method. Deposition of vaterite/PCL, vaterite-GO/PCL and vaterite-rGO/PCL composite coating on TNT-Ti was carried out by dip coating method. The composite coatings were characterized for their phase content, morphological features and functional groups. Among the three types of composite coatings, vaterite-rGO/PCL composite coating is found to be capable of encapsulating CPF-HCl to a level of 75.14 μg. The drug release profile of CPF-HCl from the vaterite-rGO/PCL composite coating exhibits a controlled release amounting to only 35.02 % of release at the end of 120 h. The vaterite-rGO/PCL composite coating exhibits a low dissolution rate and possesses adequate bioactivity in HBSS and SBF solutions at 37 °C for 14 and 10 days, respectively. The in situ loaded CPF-HCL drug on vaterite microspheres, PCL polymer matrix and GO/rGO nanofillers does not affect the cytocompatibility and all the composite coatings supported cell viability and proliferation. The ability of vaterite-rGO/PCL composite coating to provide a slow and steady release of antibiotics with sufficient bioactivity and biocompatibility at the tissue implant interface makes it a promising for osteomyelitis infection of bone tissue implant materials.     

Synthesis and Characterization of TiN‐coated Cubic Boron Nitride Powders

Titanium nitride‐coated cubic boron nitride (TiN/cBN) composite powders were prepared by nitridizing TiO₂/cBN powders in a NH₃ flow at 950°C. The TiO₂/cBN powders were synthesized via a sol‐gel process using tetra‐butyl titanate and concentrated‐HNO₃‐treated BN powders as starting materials. The techniques of XRD, SEM, TEM, FT‐IR, and TG‐DTA were used to characterize the products and their intermediates. The cBN powders were uniformly coated with TiN nanoparticles. During the nitridization, the morphology of the TiO₂/cBN powders is unchanged. The TiN/cBN powders can be used as starting materials to prepare polycrystalline cBN compacts, or as reinforcements to strengthen metal‐matrix composites.