ZrO2 Content Research Articles

Influence of zirconium(IV) in polyurethane based on hydroxyl telechelic natural rubber for coating application

Polyurethane (PU) based on an eco-friendly renewable resource, namely hydroxyl telechelic natural rubber (HTNR), was in situ prepared using one-shot polymerization with zirconium(IV) oxide (ZrO2) incorporated. The modification of HTNR, preparation of PU together with the interactions of PU and ZrO2 surfaces were examined using FTIR, ATR-FTIR, and 1H-NMR. Also, the optimal ZrO2 content in PU matrix was used to coat carbon steel and the intrinsic properties of the composites were determined. It was found that tensile strength, Young’s modulus, hardness, abrasion resistance, and thermal stability of PU/ZrO2 composites increased with ZrO2 content, particularly at 2 wt% of ZrO2, owing to the homogeneous dispersion of ZrO2 throughout the PU matrix. After coating, the PU/ZrO2 composites showed good pencil hardness, adhesive performance, gloss, and wettability on the carbon steel substrate, enabling simple coating process and cost-effectiveness.

Microstructure and growth characteristics of Al2O3/Er2O3/ZrO2 solidified ceramics with different compositions

Directionally solidified Al2O3/Er2O3/ZrO2 ceramics were prepared with high frequency induction zone melting. Their phase components, microstructure and growth characters were investigated. The results indicated that the raw material powder with uniform oxides’ distribution could be obtained via the green body’s crushing and second ball-milling, which was benefited to get the fined and unified eutectic microstructure. The phase components of each sample were consistent with the prediction originated from the position of their composition in the phase diagram. The microstructures of eutectic and hyper/hypo-eutectic were basically a network with interpenetrated crystal phases, and a small amount of coarsened phase existed in the form of colony structure in the latter, the microstructure was refined with the increase of the ZrO2 concentration. The quasi-eutectic with colony structure could be prepared at the molar ratio of raw materials determined by the volume fraction. In addition, a large number of coarsened phases appeared in the microstructures of the samples with the eutectic molar ratios, so the corresponding samples were non-eutectic. These results demonstrated that the composition might be more important than the growth rate in the preparation of non-eutectic samples with eutectic microstructure, and the selection of the composition of solidified ceramics should not depend too much on the phase diagram. The eutectic growth could be divided into four processes according to the microstructures of precursor and solidified ceramics.

Phase Formation and Thermal Stability of Reactively Sputtered YTaO4-ZrO2 Coatings.

Y(1−x)/2Ta(1−x)/2ZrxO2 coatings with 0 to 44 mol% ZrO2 were synthesized by sputtering. Phase-pure M’-YTaO4 coatings were obtained at a substrate temperature of 900 °C. Alloying with ZrO2 resulted in the growth of M’ along with t-Zr(Y,Ta)O2 for ≤15 mol%, while for ≥28 mol%, ZrO2 X-ray diffraction (XRD) phase-pure metastable t was formed, which may be caused by small grain sizes and/or kinetic limitations. The former phase region transformed into M’ and M and the latter to an M’ + t and M + t phase region upon annealing to 1300 and 1650 °C, respectively. In addition to M and t, T-YTa(Zr)O4 phase fractions were observed at room temperature for ZrO2 contents ≥28 mol% after annealing to 1650 °C. T phase fractions increased during in situ heating XRD at 80 °C. At 1650 °C, a reaction with the α-Al2O3 substrate resulted in the formation of AlTaO4 and an Al-Ta-Y-O compound.

Structural, optical, and gamma-ray shielding properties of a newly fabricated P2O5–B2O3–Bi2O3–Li2O–ZrO2 glass system

A new glass network consists of (40–x)P2O5 + 30B2O3 + 20Bi2O3 + 10Li2O + xZrO2 where x is ranged between 0 and 5 mol% and was fabricated using a quenching method at temperature ranged between 1050° and 1380 °C. It has been observed that there is an increase in the ZrO2 substitution ratio with the glass melting temperature increased gradually. Moreover, by using the XRD spectrometer, it was verified the amorphous state of the glass samples. The absorbance and refractive index were measured experimentally using the UV–Vis–NIR spectrophotometer. Other essential optical parameters such as energy gap, Urbach energy, extinction coefficient, electrical polarizability, molar fraction, and dielectric constants were calculated based on the refractive index's experimental results. Moreover, the fabricated glass samples' ability to stand against the gamma energy and fast neutron were examined using simulation code MCNP-5 and the theoretical calculation by the latest Electron Photon Interaction Cross Section 2017 photoatomic library. The linear attenuation coefficient (LAC) exhibits a good performance when replacing the P2O5 by ZrO2 contents. The LAC at gamma-ray energy (0.015 MeV) was enhanced from 207.112 to 274.831 cm−1, increasing the ZrO2 replacing ratio between 0 and 5 mol %, respectively. The mass attenuation coefficients (µm) were found to have higher values for the library interpolation as compared to MCNP-5 simulations. The prepared glasses' ability to absorb the incoming fast neutron was diminished from 0.0251 to 0.0245 cm2 g−1, increasing the ZrO2 substitution ratio between 0 and 5 mol %, respectively.

Effect of ZrO2 addition on electrical and mechanical properties of B2O3–PbO–Li2O3 glasses

In this work, the electrical and mechanical properties of 40B2O3+40PbO+ 20Li2O3+xZrO2 (where x = 0.0, 0.25, 0.5, and 1.5 wt%) were experimentally investigated. The electrical and dielectric data were measured in the temperature range of 20–300 °C. Based on Makishima–Mackenzie's model, a total of dissociation energy (Gt) and the ionic packing density (Vt) for the investigated specimens were calculated. Then, the mechanical features, including Poisson's ratio and elastic moduli, were calculated. It was found that Vt decreased in the range of 0.3708–0.3051 m3 mol−1, while the Gt was enhanced in the range of 34.74 × 106 - 35.8803 × 106 kJ m−3 as the ZrO2 content increased. Young's modulus changed from 25.7637 to 21.8953 GPa. At the same time, the shear modulus was found to change from 11.4460 to 10.4782 GPa. The bulk modulus varied from 11.464 to 8.0167 GPa; the longitudinal modulus varied from 26.7255 to 21.9877 GPa. The values of Poisson's ratio were found to change from 0.1254 to 0.0448. The electrical results revealed that the addition of ZrO2 minimized the electrical conductivity in the temperature range of 20–300 °C; besides, it maximized the activation energy.

The influence of various zirconia contents on crystallite sizes, shrinkage, and physical and mechanical properties of hydroxyapatite-based nanobiocomposites

Carbonated hydroxyapatite (CHA)-based nanocomposite powders with different zirconia (ZrO2) contents, up to 8 wt.%, were prepared using high-energy ball mill. Phase composition of the resultant nanocomposites was investigated by X-ray diffraction (XRD) technique. Moreover, the crystal size, lattice strain and dislocation density were calculated. In order to measure shrinkage, physical and mechanical properties of these nanocomposites, their powders have been consolidated and sintered at 1000 °C. The results revealed that the gradual increase in ZrO2 contents caused increase in the lattice strain and dislocation density. On the opposite side, their crystal sizes decreased with increasing ZrO2 content. Moreover, the mechanical properties including microhardness, compressive strength, Young's modulus, elastic modulus, bulk modulus, shear modulus and Poisson's ratio of the sintered nanocomposites were greatly improved with increased ZrO2 contents until they reached 7 GPa, 165 MPa, 57 GPa, 70 GPa, 47.5 GPa, 22 GPa and 0.267, respectively for the sample containing the highest ZrO2 content. However, in spite of the great importance of ZrO2 contents on the mechanical properties, they caused noticeable increases in the porosity of the sintered samples. Additionally, increasing of ZrO2 contents, up to 8 wt.%, reduced the shrinkage percentages from 12.3% to 9.5%.

Microstructural evolution and interfacial reactions between Ti and ZrO2/CaTiO3 composites

AbstractVarious proportions of ZrO2/CaTiO3 powders were mixed and hot pressed at 1500°C/30 min for Ti casting. The hot‐pressed ZrO2/CaTiO3 composites were reacted with pure Ti at 1700°C/10 min in Ar. The interfacial reaction between Ti and ZrO2/CaTiO3 composites was investigated through X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy‐dispersive X‐ray spectroscopy. The ZrO2/CaTiO3 composites with less than 10 vol.%, CaTiO3, and a minor amount of residual TiO2 were found. When the content of ZrO2 was increased to larger than 10 vol.%, two Ca2Zr5Ti2O16 and CaZrTi2O7 phases appeared in the composites. The amount of CaTiO3 and CaZrTi2O7 in the composites gradually decreased as the amount of ZrO2 increased. When Ti came in contact with ZrO2/CaTiO3 composites with less than 10 vol.% ZrO2, the resulting eutectic reaction produced a liquid phase and induced melting. When ZrO2 was increased to more than 30 vol.% in the composites, Ca2Zr5Ti2O16 and CaZrTi2O7 changed completely to CaZrO3, Ti2O, CaO, and ZrO2. With more than 30 vol.% ZrO2, no other reaction phases occurred in the Ti side after contact with the ZrO2/CaTiO3 composites, which is conducive for producing ceramic composites for Ti casting applications.

Zirconia-Alumina Composites Obtained by Centrifugal Slip Casting as Attractive Sustainable Material for Application in Construction.

This paper focuses on the possibility of adapting the centrifugal slip casting method to obtain zirconia–alumina composite materials in the form of finished tube-shaped products. These types of products, due to their unique properties, can be utilised, for example, in the transport of aggressive substances, even in extreme temperatures or corrosive conditions. The study reports on the two series of zirconia–alumina composites differing in the content of ZrO2—2.5 and 25 vol%. The fabricated and sintered materials were characterised using scanning electron microscopy (SEM), X-ray diffraction (XRD) and stereological analysis. Moreover, a life cycle assessment (LCA) was provided in accordance with the requirements of the ISO 14044 and EN 15805 standards. The obtained data clearly show that the centrifugal slip casting method allows obtaining samples with high density and extremely uniform distribution of the ZrO2 phase in the alumina matrix. The stereological analysis results proved also that the addition of ZrO2 is effective in reducing the growth of Al2O3 grains during the sintering process. The phase analysis carried out by means of XRD showed that during the sintering process, in the case of composites with a lower ZrO2 content (2.5 vol%), the monoclinic to tetragonal transformation of ZrO2 was total, while for samples containing 25 vol% ZrO2, the monoclinic phase remained in a small amount in the final product.

Preparation cordierite and zirconia-doped cordierite composite & study bioactive properties

The current study focused on studying the bioactive behavior of pure cordierite which by sol- gel technique. Cordierite gel is combined with water-based sol–gel course, beginning from fundamental magnesium carbonate and Al (NO3) 3 inorganic arrangement broke up in silica-ethanol sold. Zirconia-doped cordierite composite also prepared by a new precipitation procedure with the composition of (5–15 wt%) of ZrO2. The cylindrical samples in 13 mm diameter for the next tests were formed by cold pressing at 150 MPa then sintering at 1350 °C. The, X-ray analysis, and SEM technique were applied to find the microstructure . The bioactivity properties of produced powder were determined after immersing for 21 days in the stimulated body fluid (SBF) solution which appearance compact layer of hydroxyapatite (HA) that exhibits a biological activity with increase the amount of ZrO2 as compared with pure cordierite. Biodegradation test was done by soaking synthesized powder in the trees-HCl buffer solution for 7 days and weight loss of samples was determined the increase in weight loss is detected as the content of ZrO2 in the samples increases with respect to pure samples. Cytotoxicity estimation has done, by RAW macrophage similar the media cell line for a period of growth of 48 h. The cell addition, trainings on the powder prepared, sample, display perfect attraction between compact surface and cells.

Effect of zirconia content on properties of Al7050 alloy composites by stir casting method

Aluminium based metal matrix composites (AMMCs) are most prominence materials for using various applications like aerospace, automotive and defence industries owing to their favorable properties. The aim of the current research work involves Al7050 alloy matrix reinforced with varying 0, 4, 8 and 12 wt% of zirconia (ZrO2) content by using stir casting method. The effect of ZrO2 content on the properties such as hardness, tensile strength, elongation, impact strength and wear rate for the produced composites were examined. The microstructure of the proposed composite evident the uniform distribution of ZrO2 content into the matrix. The experimental result showed that the addition of 12 wt% ZrO2 particles in the Al7050 alloy enhanced the maximum strength and hardness properties. But, the elongation of produced composites gradually decreased with increasing the ZrO2 reinforcement particles. The scanning electron microscope (SEM) was employed to investigate the tensile fractography of Al7050-12 wt% ZrO2 composite. The minimum wear rate of 0.0034 mm3/m was achieved by the inclusion of 12 wt% ZrO2 content.

Some Aspects of the Geochemistry and Natural Radioactivity of the Azov Deposit Ores

The analysis of the Azov deposit of zirconium-rare earth ores as the object capable on qualitative and quantitative parameters to become key for creation and modernization of rare earth subsectors of the industry of Ukraine is carried out. On the basis of the generalized characteristics of zirconium-rare earth mineralization, conclusions were drawn regarding the nature of the increased radioactivity at the Azov deposit, which is mainly due to the presence of certain minerals in the ores. The actual radioactive minerals were found only as inclusions in zircon and do not make a significant contribution to the natural radioactivity of ores. It has been established that the radioactivity is uranium-thorium due to the inclusion of these elements in the composition of the aforementioned minerals. The results of the radiation-hygienic assessment of core samples from the deposit are presented. According to the existing standards, the enclosing rocks of the supra-ore and under-ore strata can be used in all types of construction without restrictions. The ores of the deposit are assigned to the third class in terms of the level of effective specific activity. It was found that there is a significant direct relationship between gamma activity and the total REE content in the field. There is also a correlation between the content of U and Th, the dose rate of γ-radiation and the content of the total REE. It was shown that there is no relationship between these indicators and the ZrO2 content. Analysis of the gamma-ray logs showed the possibility of confidently drawing the boundaries of the ore intervals and fixing the inter-ore intervals. The main stages of the technological process of integrated development, enrichment, processing and storage of enrichment tailings, slags and sludge, which ensure the minimum impact of production on the environment and human health, have been determined.

Study of novel, thermally resistant Mg alloy with dual-phase

A novel, thermally resistant, dual-phase Mg alloy was prepared, and the microstructural evolution and tensile properties were investigated. The results showed that the Mg alloy matrix mainly consisted of the α-Mg and β-Li phases, and the solidified microstructure was gradually refined with increasing ZrO2 incorporation. The tensile properties of the extruded and annealed alloys were markedly improved with increasing ZrO2 content. After annealing at 603 K for 8 h, the alloy strength remained almost stable, whereas the plasticity increased. Analysis of the evolution of the properties and fracture morphology showed that this type of Mg alloy possessed good thermal resistance and formability.

Formation Mechanism of the Velyka Vyska Syenite Massif (Korsun-Novomyrhorod Pluton, Ukrainian Shield) Derived from Melt Inclusions in Zircon

The formation of leucosyenites in the Velyka Vyska syenite massif was provoked by the liquation layering of magmatic melt. This assumption is based on the presence of two primary melt inclusions of different chemical composition in zircon crystals from Velyka Vyska leucosyenites. They correspond to two types of silicate melts. Type I is a leucosyenite type that contains high SiO2 concentrations (these inclusions dominate quantitatively); type II is a melanosyenite type that contains elevated Fe and smaller SiO2 concentrations. The liquation layering of magmatic melt was slow because the liquates are similar in density; leucosyenite melt, which is more abundant than melt of melanosyenite composition, displays greater dynamic viscosity; the initial sizes of embryos of melanosyenite composition are microscopic. Sulphide melt, similar in composition to pyrrhotite, was also involved in the formation of the massif. Zircon was crystallized at temperatures over 1300°С, as indicated by the homogenization temperatures of primary melt inclusions. The REE distribution spectra of the main parts (or zones,) of zircon crystals from the Velyka Vyska massif are identical to those of zircon from the Azov and Yastrubets syenite massifs with which high-grade Zr and REE (Azov and Yastrubets) ore deposits are associated. They are characteristic of magmatically generated zircon. Some of the grains analyzed contain rims that are contrasting against the matrix of a crystal, look dark-grey in the BSE image and display flattened REE distribution spectra. Such spectra are also typical of baddeleyite, which formed by the partial replacement of zircon crystals. The formation of a dark-grey rim in zircon and baddeleyite is attributed to the strong effect of high-pressure СО2-fluid on the rock. The formation patterns of the Velyka Vyska and Azov massifs exhibit some common features: (а) silicate melt liquation; (b) high ZrO2 concentrations in glasses from hardened primary melt inclusions; (c) the supply of high-pressure СО2-fluid flows into Velyka Vyska and Azov hard rocks. Similar conditions of formation suggest the occurrence of high-grade Zr and REE ores in the Velyka Vyska syenite massif.

Dependence of the refractive index of transparent ZrO2–SiO2 aerogels on the density and zirconium content

In this work ZrO2–SiO2 aerogels with ZrO2 content of 3, 6 and 10 mol. % in the form of transparent blocks were synthesized using the sol-gel method. The possibility of introducing ZrO2 into a SiO2 aerogel without considerable decline of the optical characteristics of the material was shown for the first time. Aerogel samples were studied by several techniques including UV–Vis, ATR-FTIR spectroscopy and nitrogen adsorption, the refractive index was determined using beam tests (“Extracted beams” of the VEPP-4M complex). It was shown that the addition of ZrO2 to SiO2 aerogel increases the refractive index without increasing of the aerogel density. For the first time, the possibility of obtaining highly transparent ZrO2–SiO2 aerogel blocks with acceptable optical characteristics for radiator in Cherenkov detectors has been demonstrated. This result makes it possible to achieve high refractive indices in the production of aerogel blocks for Cherenkov detectors to increase their performance.

The difference of surface roughness in acrylic resin self-cured with addition of zirconium dioxide particles as a denture repaired materials

Background: Tooth loss is one of the effects of periodontal disease and dental caries. Tooth loss can be resolved by making a denture prosthesis. Several factors that influence society on denture use include aesthetic, social, func-tional, educational, and cultural factors. The large number of lost teeth will certainly increase the demand or desire to manufacture dentures to restore the function of the missing teeth. One of the materials that are often used in den-tures is acrylic resin. Acrylic resins frequently used for denture base materials are cold polymerized acrylic resin and hot polymerized acrylic resin. Cold polymerized acrylic resin uses chemical activation, and this type of resin is often used for denture repair materials. Denture repair aims to repair prostheses that have many fractures in the mid-line area. Chemical polymerization acrylic resin is often used as a repair material because it is easy to apply and can be done directly on the patient. This resin has a disadvantage because it often leaves residual monomer in the polymerization process, so it impacts porosity. This problem can be overcome by modifying the resin's chemical structure using polyethylene glycol or by adding ZrO2. Objective: This study aims to determine the effect of adding 3%, 5%, and 10% of zirconium dioxide (ZrO2) nanoparticles to the surface roughness of self-cured acrylic resin as a denture repair material. Methods: Four sample groups, each consisting of 10 samples, were divided into the con-trol group (K), the treatment group with ZrO2 addition 3% (P1), the treatment group with the addition of ZrO2 5% (P2), and the treatment group with the addition of ZrO2 10% (P3). The results of all treatments and controls were tested for surface roughness using the MST-301 surface roughness test profilometer. Results: Based on the results of the descriptive test, the mean of group K = 0.395 ± 0.161, group P1 = 0.813 ± 0.525, group P2 = 1.284 ± 0.336 and group P3 = 1.093 ± 0.558. In the Kruskal-Wallis test, there were significant differences in all groups. Conclusion: The self-cured acrylic resin with the addition of 3% concentration of ZrO2 has the lowest surface roughness com-pared to the other groups, and the roughness is almost similar to the surface roughness of the control group.

Evaluating compressive property and hot deformation behavior of molybdenum alloy reinforced by nanoscale zirconia particles

The paper deals with the fabrication of molybdenum alloy bars with different ZrO2 content via a series of processes, involving hydrothermal synthesis, co-precipitation, co-decomposition, powder metallurgy and rotary swaging. The compressive properties of molybdenum alloy bars were tested at various temperatures from room temperature to 1400 °C, and hot deformation behavior at different temperatures and strain rates was studied. The results show that ZrO2 particles with the size of tens of nanometers are evenly dispersed in Mo matrix, and ZrO2(110) and Mo(110) have a non-coherent interface due to a larger lattice misfit 13.57%. ZrO2 particles could significantly reduce grain size of molybdenum alloy and improve its compressive properties. When the volume content of zirconia increases from 0% to 2.0%, the grain size of molybdenum alloys annealed at 1200 ℃ decreases sharply from 55.9 µm to 3.5 µm. The compressive yield strength (CYS) of Mo-2.0 vol%ZrO2 annealed at 1200 °C is 674 MPa at room temperature, which is 65.6% higher than that of pure Mo. The high temperature CYS of Mo-2.0 vol% ZrO2 at 1400 °C is 176 MPa, increasing 49.6% higher than that of pure Mo. Compared with the previous works, the peak flow stress of the new Mo-2.0 vol%ZrO2 has been significantly improved. Adding of 2.0 vol%ZrO2 increases the initial temperature of dynamic recrystallization to 1200 °C, and effectively prevents the grain growth of dynamic recrystallization even at the increased deformation temperature of 1400 °C.

Protective and decorative properties of titanium glass enamels

It is known that enamel coatings with enhanced protective and decorative properties can be fabricated on the basis of boron-silicate glass frits with an increased content of TiO2 in their composition. Opacity and white color of enamel coatings are due to their crystallization at firing temperatures. Titanium glass enamels are not pure white visually, and show yellow and blue shades depending on their chemical composition. The purpose of this work was to establish the influence of basic components on the water resistance and color characteristics of titanium enamel coatings. Our experimental study was focused on the glass frits with the chemical composition described by the generalized formula (76–n–m)SiO2nB2O3mNa2O24MexOy, where MexOy is the total content of TiO2, ZrO2, Al2O3, MgO, СaO, P2O5, and K2O. It was found that the glass frits with the following content of basic components (mol.%): Na2O 12–13, K2O 3, B2O3 10–11, SiO2 49–51 demonstrated the highest water-resistant properties. The color characteristics of titanium enamel coatings prepared on the basis of the mentioned glass frits differ significantly from the reference white light A; the titanium enamel coatings under consideration have a yellow-green tint. The highest deviations of the enamel coating color purity and color tone from a standard of white color were observed when increasing the Na2O content in the glass frits composition at the expense of SiO2. The color of titanium coatings with the highest water resistance has a deviation from the standard of white color within 4–6%.

Preparation and Electrochemical Performance of the Stainless Steel/α-PbO2-ZrO2/β-PbO2-ZrO2-CNT Composite Anode

A novel stainless steel/α-PbO2-ZrO2/β-PbO2-ZrO2 (30 g l−1)-CNT (10 g l−1) modified by carbon nanotube (CNT) and ZrO2 co-doping was prepared by pulse electrodeposition. The effect of ZrO2 and CNT concentration on the chemical composition, surface morphology, electrocatalytic activity and corrosion resistance of the composite anode materials was studied by anodic polarization curve (LSV), cyclic voltammetry curve (CV), Tafel curve, scanning electron microscope (SEM) and X-ray diffraction (XRD). The results show that the surface of the electrode modified by CNT (30 g l−1) and ZrO2 (10 g l−1) has a larger active area and smaller crystallite particles. The formed deposit is flat, dense and crack-free. The electrode has more corrosion resistance. Compared with the stainless steel/α-PbO2-ZrO2/β-PbO2 and the stainless steel/α-PbO2-ZrO2/β-PbO2-ZrO2 (30 g l−1) anode, the stainless steel/α-PbO2-ZrO2/β-PbO2-ZrO2 (30 g l−1)-CNT (10 g l−1) anode has a lower oxygen evolution potential, better electrocatalytic activity, and stronger corrosion resistance.

WITHDRAWN: Mechanical properties and characterization of Al7075 aluminum alloy based ZrO2 particle reinforced metal-matrix composites

Abstract In the present study, the influence of ZrO2 content on the mechanical and wear properties of Al7075 Aluminium alloy composites were investigated. Aluminium Al7075 alloy composites with varying weight percentage of reinforcement (3, 6, 9, 12) were successfully fabricated by compocasting process. Characterization studies were conducted on the developed composite samples to evaluate the microstructural and mechanical properties. The micrographs and EDAX images conforms the homogeneous distribution of the reinforcement in a soft aluminium rich matrix with micro porosities. The test results indicate increasing behavior in the hardness and ultimate tensile strength of the composites. The large increase in the properties was observed up to the reinforcement percentage of 6% and the improvement is minimal after that. The improvements in properties are mainly due to better distribution of the reinforcement and good interfacial bonding. Maximum hardness of 70BHN and ultimate tensile strength 218Mpa were observed. The Pin on disc wear test conducted on the specimen shows the wear rate and coefficient of friction values were decreasing with the increase in the percentage of reinforcement.

Effect of Chopped ZrO2 Fiber Content on the Microstructure and Properties of CaO-Based Integral Ceramic Mold.

A chopped ZrO2 fiber (ZrO2 (f)) reinforced CaO-based integral ceramic mold was successfully fabricated by stereolithography (SLA) and tert-butyl alcohol (TBA)-based gel-casting, and the effect of chopped ZrO2 (f) content on properties of the ceramic mold was investigated. The results show that the ZrO2 (f) content had a significant effect on the viscosity of CaO-based ceramic slurry, which directly affects the filling ability of slurry in complex structures of the integral mold. The tiny structures of the ceramic mold cannot be filled completely with a ZrO2 (f) content exceeding 3 vol %. The sample fabricated with 3 vol % fiber content showed a harmonious microstructure and exhibited an excellent comprehensive performance with 25 °C bending strength of 22.88 MPa, an 1200 °C bending strength of 15.74 MPa, a 1200 °C deflection of 0.86 mm, and a sintering shrinkage of 0.40%, which can meet the requirements of casting very well.