ZrO2 Samples Research Articles

Antifungal activity and cytotoxicity study of ZrO2-ZnO bimetallic nanoparticles

Antifungal resistance of Candida species is a growing concern worldwide. Therefore, this study presents the synthesis of ZnO and ZrO2-ZnO nanoparticles. Structural features of the nanoparticles are characterized by DLS, SEM, EDX, UV–Visible and Raman spectroscopy. Thereafter, the investigation of the effect of these nanoparticles on Candida species was performed by disk diffusion and broth microdilution method on C. albicans, C. dubliniensis, C. glabrata, and C. tropicalis. The viability activity was also evaluated. Scanning electron microscopy showed spherically shaped nanoparticles while dynamic light scattering analysis showed ZrO2 (76 nm), ZnO (22 nm) and ZrO2-ZnO samples between 26 nm and 34 nm respectively. The elemental analysis validated that pure samples were synthesized. The Raman spectra shows ZnO nanoparticles of the wurtzite crystal structure having a group theory that confirms the presence of optic nodes with different properties. Our investigations have shown that mixing ZrO2 with ZnO nanoparticles only show inhibition effect on Candida species at high concentration of ZnO against ZrO2 based on the inhibition zone formed in the disk diffusion and the decrease in the growth characteristics recorded from the broth microdilution analysis. The viability study shows that there is no significance difference in viability as a function of time and concentration on the peripheral human mononuclear cells on exposure to the synthesized nanoparticles.

Phase transformation and enhanced blue photoluminescence of zirconium oxide poly-crystalline thin film induced by Ni ion beam irradiation

Swift heavy ions (SHI) irradiation of Nickel (Ni) beam with different ions fluence bring the modifications in the functional properties of radio frequency (RF) grown zirconium oxide (ZrO2) nanocrystalline thin films. X-ray diffraction analysis affirms the monoclinic to tetragonal phase transformation and diminishing of peak at higher fluence 1 × 1014 and 2 × 1014 ions/cm2 induced by electronic excitation caused by SHI. Zirconium oxide thin films exhibit the same thickness (195 nm) of virgin and irradiated samples and whereas the nanocrystalline thin films have the elemental composition in proper stoichiometry (1:2) as analyzed by rutherford backscattering spectroscopy (RBS). Photoluminescence measurements confirm the blue emission of virgin and irradiated sample recorded at excitation wavelength 270 to 310 nm. The intensity of obtained emission bands varies with fluence which is interpreted in terms of generation and annihilation of defect centers. The characteristic Ag and Bg Raman modes of monoclinic and tetragonal ZrO2 are obtained at different positions. Moreover, the nanocrystalline ZrO2 thin films exhibits the most prominent absorption phenomenon in the visible range and the irradiation cause significant decrease in band gap to 3.69 eV compare to the virgin ZrO2 sample (3.86 eV). XPS analysis indicates the shifting of the core levels Zr 3d and O 1s towards higher binding energy and spin—orbit splitting of different states. The findings in this research justify that the irradiated thin films can be a potential candidate for designing of new materials, intense radiation environments, nuclear reactors, nuclear waste systems, clean energy sources.

Study of mechanical properties and wear behavior of nano-ZrO2-hardened Al2024 matrix composites prepared by stir cast method

The Al2024 matrix composites reinforced by different weight percentages of nano-ZrO2 particles prepared by stir-cast method. Physical and mechanical properties (microhardness, compressive test and elastic moduli) of the prepared composites samples were measured. Moreover, the effect of sliding distance and applied load on the wear behavior of all prepared samples was studied. The results showed that the relative density of the Al2024 matrix decreased with increase of the nano-ZrO2 particles while the apparent porosity increased. Moreover, significant improvement in mechanical properties, for example microhardness, ultimate strength, strengthening efficiency and Young’s modulus. The wear rate decreased as the reinforcement content increased while it increased with the increase of the sliding distance and applied load. The microhardness, ultimate strength, bulk modulus of the composites containing 10 wt.% ZrO2 sample improved to approximately 31, 60 and 49%, respectively. For the same sample, the wear rate improved around 20.2 and 21.3 under applied loads 10 and 40 N, respectively.

Synthesis and characterization of nanostructured copper and lanthanum co‐doped zirconia for voltammetric sensing of tumor biomarkers

AbstractNanostructured ZrO2‐based materials with their biocompatibility, excellent electrical, and surface charge properties became one of the best candidates for the electrochemical sensing applications. Here, synthesis of Zr1‐xCuxLaxO2 compounds was achieved in nanoscale and fully characterized using XRD, TEM, DRS, and cyclic voltammetry. A mixture of monoclinic and cubic phases was detected for the undoped ZrO2 (Z sample, x = 0). For the Cu‐doped compounds, (ZFW1, x = 0.05 and ZFW2, x = 0.1), a combination of cubic fluorite and monoclinic phase were detected. The intensity of the monoclinic phase for the Cu‐doped was higher than that of the undoped ZrO2 sample. Cu and La co‐doped samples (ZL1C1, x = 0.05 and ZL2C2, x = 0.1) were stabilized in a single cubic phase structure. Therefore, their band gap dropped from (4.8 eV) for the undoped ZrO2 to (1.49 eV) for the ZL1C1 sample and (2 eV) for the ZL2C2 sample. Voltammetric sensing of neurotransmitter metabolites (vanillylmandelic acid (VMA) and homovanillic acid (HVA)) was achieved using the modified electrodes due to their acquired high electrocatalytic and high electrochemical performance.

Mn doped ZrO2 nanoparticles: An optically tuned photocatalyst with superior structural, magnetic and dielectric characteristics

In the present study, pristine ZrO2 and Mn doped zirconia nanoparticles (NPs) were synthesized by a simple co-precipitation technique. A comprehensive structural and spectroscopic analysis confirmed the purity of the tetragonal phase and the successful inclusion of Mn ions in the zirconia lattice. SEM and TEM analysis showed fine morphology with a narrow size distribution. Spectroscopic analysis revealed that Mn–ZrO2 NPs exhibit enhanced light absorption capacity, tuned band gap and good control over the rate of recombination of electron-hole pairs owing to the surface defect states and oxygen carriers/vacancies. In addition, the introduction of Mn contents into the ZrO2 lattice has significantly improved the dielectric properties. Zeta potential measurements have confirmed the stability of prepared photocatalysts. All prepared nanoparticles were catalytically evaluated for the decomposition of the methylene blue (MB). Interestingly, 10 % Mn–ZrO2 NPs have illustrated a peak efficiency of 96.2 % against MB dye after 160 min, making Mn-modified ZrO2 NPs a potentially visible light-activated photocatalyst. The present study not only showed room temperature ferromagnetism for all pure and Mn–ZrO2 samples, but also investigated the effect of tailored physiochemical characteristics on photocatalytic activity to get better insights into the ecological applications.

Effect of ZrO2 particles on the nanomechanical properties and wear behavior of AlCoCrFeNi–ZrO2 high entropy alloy composites

AlCoCrFeNi-x ZrO2 (x = 0, 5, and 10 (wt. %)) high entropy alloy (HEA) matrix composites were prepared by mechanical alloying (MA) and spark plasma sintering (SPS) methods. Microstructural studies showed that the prepared samples mainly consisted of FCC and BCC phases. Also, small contents of Al-rich and Cr-rich phases were observed. According to microhardness analysis, the addition of 10 wt% monoclinic zirconia enhanced the hardness of FCC and BCC phases from 3.42 to 4.48 GPa and 7.00 to 8.52 GPa, respectively. The wear rate calculations showed that using 5 wt% monoclinic zirconia only slightly improved the wear resistance compared to AlCoCrFeNi HEA sample, due to a balance between the positive effect of zirconia addition and the negative effect of BCC phase decrement. However, the wear resistance was considerably enhanced with increasing zirconia content to 10 wt%. Improved H/E ratio of BCC and FCC phases and the reinforcing effect of zirconia particles in this sample are the main effective factors in the enhancement of wear resistance of AlCoCrFeNi-10 wt% ZrO2 sample. In all samples, there were four wear mechanisms including abrasive, adhesive, oxidation, and delamination.

Optical Efficacy of Titanium Nitride-Coated Abutment Material on Soft Tissue Discoloration: A Spectrophotometric In Vitro Analysis.

The objective of this investigation was to assess the extent of mucosal discoloration caused by different CAD/CAM abutment materials and to determine the influence of mucosa thickness on the subsequent color, with a particular focus on titanium nitride. In a pig maxilla, a trapdoor-shaped mucosa flap was prepared unilaterally. Several CAD/CAM abutment materials were used to assess a number of clinical scenarios. Varying mucosa thicknesses were simulated by connective tissue grafts harvested at the contralateral side of the palate, resulting in layer thicknesses of 1.5, 2, and 3 mm. Titanium (Ti), zirconia (ZrO2), and titanium nitride (TiN) served as test specimens with and without ceramic veneering. Color differences (ΔE) and deviations in brightness (L), chroma (C), and hue (H) were determined spectrophotometrically, comparing the measured value of the native tissue and the results obtained with different materials at varying mucosa thicknesses. All tested specimens caused a mucosa discoloration in comparison to the native tissue, diminishing with increasing mucosa thickness. The use of TiN demonstrated the least mucosa discoloration in thin soft tissue of 1.5 mm, with a mean ΔE value of 1.93 (P = .004). While ZrO2 revealed a comparable ΔE value of 2.13 (P = .022) at a tissue thickness of 1.5 mm, Ti showed the highest mucosa discoloration above the visibility threshold of ΔE = 3.1, with a mean ΔE value of 4.07 (P = .002). Ceramic veneering of the Ti samples led to a considerable reduction in soft tissue discoloration, with a resulting ΔE value of 2.2. The veneering of TiN and ZrO2 samples with porcelain, on the other hand, had no noticeable effect on the mucosa color. CAD/CAM abutment materials cause an adverse soft tissue color shift that decreases with increasing mucosa thickness. In thin peri-implant mucosa, titanium nitride and zirconia lead to the least discoloration. Due to their positive optical properties and mechanical superiority compared with ceramic abutments, gold-hue titanium nitride-coated CAD/CAM abutments could be a clinical alternative in cases of thin peri-implant mucosa.

Mechanical property enhancement of high-plasticity powder metallurgy titanium with a high oxygen concentration

High-plasticity titanium materials with high oxygen content were prepared by powder metallurgy (PM) and hot rolling, using pure Ti and ZrO2 powder as raw materials. Completely dissolved oxygen and zirconium atoms resulted in the lattice constant change, thereby increasing the strength. Although the oxygen content was up to 0.56 wt% (much higher than the oxygen threshold of 0.33 wt%), PM Ti still exhibited high plasticity. The Ti-0.5 wt% ZrO2 sample (0.43 wt% O) had UTS of 737 MPa and EL. of 28%, while the Ti-1.0 wt% ZrO2 sample (0.56 wt% O) had UTS of 824 MPa and EL. of 15%. Compared to pure Ti, the addition of 0.5 wt% ZrO2 resulted in a noticeable increase in UTS (increased by 9%) and EL. (increased by 19%). The strength-ductility trade-off dilemma of PM Ti alloy was broken. The formation of fine and equiaxed dynamic recrystallized grains may be one of the reasons that increased the ductility. The reinforcement effect of ZrO2 was calculated as 146.7 MPa/wt% ZrO2.

Phase and luminescence behaviour of Ce-doped zirconia nanopowders for latent fingerprint visualisation

Present work focuses on the phase evolution, emission behaviour of Ce-doped zirconia nanopowders, calcined under air and argon atmosphere and its application in latent fingerprint visualisation. The different concentration of Ce-doped ZrO2 nanoparticles were prepared via precipitation method using sodium borohydride and calcined at 600 °C under air and argon atmosphere. The tetragonal phase of zirconia was detected for all samples under air atmosphere. However, the crystalline phase of tetragonal zirconia was observed for above 1 mol% Ce-doped ZrO2 samples, calcined under argon atmosphere. A broad photoluminescence emission was observed in the UV and visible range for all samples due to 5D3/2 →7FJ transitions (J = 7/2 and 5/2) of Ce3+ ions. The increase of Ce-concentration causes more distortion in the tetragonal structure of zirconia, and provides an enhanced emission intensity under air atmosphere. However, the emission intensity was found to be similar under argon atmospheric condition due to lower crystallinity of t-zirconia. Further, all the samples lie in the violet-bluish region of the CIE-diagram. The latent fingerprint visualisation was explored using Ce-doped ZrO2 nanopowders on both non-porous and porous surface, and the obtained results validate its use in the forensic applications.

Tribological properties of plasma sprayed Cr2O3, Cr2O3–TiO2, Cr2O3–Al2O3 and Cr2O3–ZrO2 coatings

Plasma sprayed Cr2O3 is widely used to protect industrial components against wear. The present study seeks to clarify how its properties can be modified by alloying with other oxides. Therefore, pure Cr2O3 and Cr2O3–25%TiO2, Cr2O3–16%Al2O3, Cr2O3–35%Al2O3, Cr2O3–10%ZrO2 and Cr2O3–20%ZrO2 coatings were studied. All samples were obtained from pre-alloyed feedstock, resulting in rather homogeneous solid solutions.Compared with pure Cr2O3 and Cr2O3–Al2O3 coatings, the Cr2O3–25%TiO2 and Cr2O3–ZrO2 ones exhibit lower indentation hardness (HIT) but higher toughness, qualitatively assessed by scratch testing. Cr2O3 and Cr2O3–16%Al2O3 also exhibit higher hardness/elastic modulus ratios (HIT/E*, HIT3/E*2) than all other samples.The sliding wear resistance of the coatings against Al2O3 and ZrO2 balls is most closely correlated to indentation hardness and, secondarily, to the hardness/modulus ratios. Pure Cr2O3 is therefore the most sliding wear resistant of all samples, whilst Cr2O3–25%TiO2 suffers very severe wear. However, ZrO2 counterparts cause systematically more severe wear than do Al2O3 ones.Dry particles' abrasion, which proceeds through flake formation, is controlled by toughness. The resistance to abrasive wear is, therefore, predicted by scratch testing. The various coatings rank almost the opposite as they did in sliding wear tests, with comparatively lower wear losses for Cr2O3–25%TiO2 and (most of all) Cr2O3–ZrO2 samples.

Synthesis of Amorphous Zirconium Dioxide from Zirconyl Nitrate in Presence of Oxalic Acid

The article presents the results of studies on preparation of amorphous zirconium dioxide from zirconium nitrate by its hydrolysis in the presence of oxalic acid. It is determined that the balance of reagents taken for synthesis (1 ml 0,025 M ZrO(NO3)2 is 1.35 ml 4 M HOOC-COOH), and the optimum temperature of the received gel drying, which is 230 ̊С, is established, too. Morphology of the obtained ZrO2 samples was explored. It has been found that the calcining temperature is independent of the size and shape forming irregular agglomerates, consisting of smaller spherical particles, whose diameter varies between 50 and 300 nm. The X-ray analysis of the sample is represented, which showed a low degree of crystallinity of the substance. IR spectroscopy data showed the presence of zirconium dioxide-characteristic peaks on the IR spectrum. The same spectrum reflects the presence of a large amount of sorbed water in the obtained sample, as well as peaks characteristic of the gas adsorbed by the sample from the environment.

Effect of Synthesis Parameters on Zirconia Phases: Tetragonal or Monoclinic?

Samples of ZrO2 were prepared by different procedures in order to figure out the most active tetragonal phase. Preparation methods differed in factors such as pH, precipitation temperature, calcination temperature, and the kind of zirconium salt (ZrOCl2 or ZrCl4). The products were characterized by XRD. It was found that the two types of salts show adverse results under the same preparation conditions. Contrary to the sample prepared using zirconium oxychloride, which showed a better result in pH between 9 and 10, the zirconium chloride samples showed a weak tetragonal peak in pH 9. In addition, Diffuse Reflectance Spectroscopy (DRS) was carried out to investigate the optical absorption properties. DRS analysis showed a strong absorption peak at about 220–230 nm and the estimated optical band gap was around 5 eV in most samples. The surface morphology of ZrO2 samples was analyzed by FESEM. The size of crystals did not change significantly with variations in calcination temperature.

Gold catalysts supported on cerium-modified mesoporous zirconia for total toluene oxidation. Effect of Ce/Zr molar ratio

Our study focused on the synthesis of gold catalysts supported on mixed Ce–ZrO2 (Ce/Zr = 0, 0.1, 0.4 and 0.9) mesoporous, which are mainly potential in the total oxidation of toluene and other volatile organic compounds. The mesoporous Ce–ZrO2 oxides (Ce/Zr = 0, 0.1, 0.4 and 0.9) were prepared via soft template strategy, using a triblock copolymer as a template. 1% of Au was loaded on mixed oxide mesoporous by deposition precipitation method. Ce–ZrO2 and Au/Ce–ZrO2 (Ce/Zr = 0, 0.1, 0.4 and 0.9) samples were characterized by XRD, N2 adsorption–desorption, H2-TPR and MET. The results showed that the dispersion of the gold particles on Ce–ZrO2 depends on the Ce/Zr ratio. These catalysts were then tested in the deep oxidation of toluene oxidation where they exhibited an excellent catalytic activity by complete decomposition of toluene at the reaction temperature equal to 576 K. This activity is correlated with the dispersion of the gold particles; itself is correlated with the Ce/Zr ratio.

Pore Structure of TiO2- Modified ZrO2 Particles Prepared by the Glycothermal Method

Titania-modified zirconias with different Ti/Zr ratios were synthesized via thermal treatment of zirconium (IV) tetra-n-propoxide and titanium (IV) tetra-iso-propoxide in 1,4-butanediol at 300 °C. The obtained products were spherical particles composed of nanocrystals with the tetragonal ZrO2 structure. The products had large specific surface areas, large pore volumes, and relatively narrow pore size distributions in the mesopore region. After calcination at high temperatures, the obtained TiO2-modified ZrO2 samples preserved large surface areas and pore structure. Having these superior thermal stability and pore structure, the obtained TiO2-modified ZrO2 particles are expected to show high performance as catalytic materials.

Phase stability and microstructure morphology of microwave-sintered magnesia-partially stabilised zirconia

In this work, microwave heating approach was introduced into the preparation process of zirconia materials to overcome the tricky technical defects during the traditional electric arc furnace method. Magnesia-partially stabilised zirconia (MgO-PSZ) with enhanced stability and a uniform microstructure was prepared via microwave heating of a ZrO2 sample manufactured by the electric arc furnace method. The effects of microwave heating on the phase stability properties, microstructure, and surface morphology of the prepared MgO-PSZ sample were evaluated via X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, and Scanning electron microscopy, and the obtained results suggested that the stability rate of the MgO-PSZ sample improved from the initial value of 81.19%–94.82% after microwave heating at 1300 °C for 1 h. As a result of the martensitic conversion of ZrO2 material, the m-ZrO2 diffraction peaks were suppressed at the same time. Additionally, a similar changing trend was noticed in the XRD pattern, Raman spectrum, and FT-IR spectrum, indicating a decrease in the m-ZrO2 phase content in the microwave treated products. Furthermore, the microstructure on the surface of the microwave-sintered MgO-PSZ sample was improved in contrast to the raw MgO-PSZ sample, and became relatively more uniform and smooth. This study determined the optimal microwave heating conditions for the preparation of MgO-PSZ material with enhanced performance, and can provided as a good foundation for developing the further related research on zirconia materials preparing by microwave heating technology.

Investigation on 3D printing ZrO2 implant abutment and its fatigue performance simulation

The zirconia (ZrO2) ceramic dental implant abutment was prepared by DLP (Digital Light Processing) 3D printing technology. The effect of different heat treatment parameters on the sintering quality of ZrO2 was studied. According to TG-DSC, XRD, Raman, SEM and other characterization methods, it could be determined that best sintering parameter was set at 1450 °C for 1.5 h. The final product has a good morphology without holes and other defects, and the relative density is 99.48%. The ZrO2 samples printed in different directions have obvious anisotropy. The three-point bending strength of the sample in the horizontal direction is better than that in the vertical direction, and the strength is 600 MPa. The fatigue load simulation results show that the smaller the pre-angle is, the smaller the maximum stress is and the higher the safety factor is.

Ion-beam induced luminescence and optical response measurement setup at IGCAR: First experimental results

A multipurpose novel experimental setup has been developed for the in situ measurements of ion-beam induced luminescence, optical response, and time-resolved photoluminescence spectroscopy of materials. A low-energy ion accelerator (terminal voltage of 150 kV) has been coupled with the spectrometer for the experiments. Measurements show a drastic increase in the luminescence intensity at 425 nm with the maximum fluence of 120 keV He+ ion irradiation on pure monoclinic ZrO2 samples. The maximum luminescence intensity is found to increase systematically with the ion fluences. An excess of oxygen defects in irradiated ZrO2 samples is thought to be the reason for the increase in the luminescence intensity. In addition, the He+ ion-beam induced increase in optical responses at 425 nm in Ag+ ion-exchanged soda glass samples, for example, has been observed on ion irradiation. The unique in situ experimental setup demonstrates and opens new opportunities to study irradiation controllable defects in materials and ion-beam induced optical responses in glass samples.

Microstructural Characterization and Wear Performance of NiTi–ZrO2 Composites

In this study, NiTi-x wt% monoclinic ZrO2 (x = 0, 5, and 10) samples were fabricated with spark plasma sintering method and the role of zirconia microparticles addition on the microstructure, martensitic transformation, and wear behavior of NiTi–ZrO2 samples was investigated. Microstructural observations using scanning electron microscopy equipped with energy dispersive spectroscopy confirmed the formation of Ti–rich regions in NiTi/zirconia interfaces. The evolution of mismatch stress in the composite samples can increase the dislocation density, especially at the interfacial regions. This facilitates the diffusion of titanium from the matrix which leads to the formation of NiTi2 phase in the composite samples. According to differential scanning calorimetry analysis, the martensitic transformation temperatures of zirconia reinforced samples increases that shows the higher stability of the martensite phase at room temperature. Rietveld refinement analysis also approved this finding. According to wear test results, the wear rate of NiTi sample is 5.74 × 10−3 mm3/N m. However, after the addition of 5 wt% ZrO2, the wear rate decreases to 1.49 × 10−3 mm3/N m which confirms the positive effect of zirconia reinforcements on the wear performance of NiTi-based samples. This improvement can be attributed to a better combination of hardness and pseudoelasticity in this sample.

Influence of the microstructure on the life prediction of hydrothermal degraded 3Y-TZP bioceramics

In this work, the effects of the microstructure on the hydrothermal degradation of yttria-stabilized tetragonal zirconia (Y-TZP) bioceramics and theoretical correlations of the zirconia grain size impact in simulations of body fluids were investigated. Samples of ZrO2 (3 mol.% Y2O3) powders were compacted and furtherly sintered for 4 h at different temperatures (1450, 1500, 1530 or 1600 °C), reaching nearly full density in microstructures with different grains sizes ranging from 0,35 ± 0,10 μm to 1,53 ± 0,34 µm. Tests of hydrothermal degradation were performed in autoclave (134 °C - 2 bar), varying the dwell time between 1 and 36 h. The growth of the ZrO2 grain size consistently affected the rate of degradation (represented by the transformed monoclinic m-ZrO2 content) of this ceramic: After 12 h of autoclaving, the monoclinic percentage quadrupled with an increase in the average grain size of 0.35 ± 0.1 μm to 1.53 ± 0.34μm. Using a theoretical correlation between the time of degradation in the autoclave and the respective time in the human body, it was possible to predict the content of the monoclinic phase present in the 3Y-TZP for up to 36 years of exposure in body fluids, and with that, mathematical equations that correlate grain size of ZrO2 with %monoclinic were proposed.

High-sensitive UV photodetector based on ZrO2 nanoparticles for humidity applications

This study developed a humidity sensor by synthesizing ZrO2 films on porous silicon (PSi) via spray pyrolysis at two substrate temperatures (300 °C and 400 °C). This is crucial as the performance of humidity sensors is strongly dependent on the microstructure and morphology of the sensing film. XRD and FESEM analysis confirmed the cubic crystal nanostructure of the synthesized ZrO2. The FTIR spectra show the presence of Si–O–Si, Si–OH and Zr–O sites at the surface of the ZrO2/PSi composite film. The ZrO2 sample prepared at 300 °C exhibited larger specific surface area and smaller particle size. Thus, the humidity sensor fabricated based on the sample prepared at 300 °C shows higher sensitivity. The humidity sensing of ZrO2 device was measured at room temperature over relative humidity (RH) of 25%,35% and 75%. The results showed that the UV irradiation strong influences the response characteristics of the sensor because it becomes a source of heat stimulation, especially at low humidity level. The fabricated ZrO2 sensor exhibited highest sensitivity of 492.66% observed when the humidity is 75% RH + UV irradiation, with faster response-recovery time in the range of (40–100) µs compared to contemporary sensors. These results confirm the applicability of ZrO2 nanoparticles on PSi as a potential material for the fabrication of simple and high performance humidity sensors.