Statement of the Problem: Despite yttria-stabilized tetragonal ZIRCONIA polycrystal (Y-TZP) high strength in dental restoration application, Zr-the framework has a low tendency to react chemically with cement which is the main reason of these restoration failures. Purpose: The aim of this in vitro study was to evaluate the effect of Y-TZP coating by NANOcomposite of silica and aluminosilicate according to the sol-gel dip-coating technique on the bond strength of resin cement to Y-TZP. Materials and Method: In this experimental study, Y-TZP blocks (10×10×3 ) were prepared and sintered and assigned into 4 groups (n=10) for coating including control group without any further surface treatment, sandblasted using 110 μ m alumina particles under 2. 5 bar and tip distance of 10 mm, silica sol dip coating + calcination, aluminosilicate sol dip coating+ calcinations. To confirm chemical bonds of sol-gel covers, Fourier transforms infrared spectroscopy (FT-IR) technique was used. The surface of the sample was investigated by scanning electron microscopy (SEM), energy-dispersive spectroscopy detector (EDS) and x-ray diffraction (XRD) methods. Micro-shear bond strengths (μ SBS) of ZIRCONIA-cement specimens were evaluated. Data were analyzed with a one-way ANOVA test in SPSS version 11. 5 software with a confidence interval of 95%. Results: μ SBS of sandblasting, NANO-silica, and NANO-aluminosilicate specimens were significantly higher than control. μ SBS of NANO-silica was higher than other groups but no significant difference was observed in μ SBS of sandblasting NANO-silica, and NANO-aluminosilicate groups (p> 0. 05). Conclusion: Covering the ZIRCONIA surface with non-invasive NANO-silica and NANOaluminosilicate using the sol-gel technique leads to improved cement bond strength.

Two- step sintering (TSS) has been applied, in the present work, to suppress the accelerated grain growth of Hydroxyapatite ZIRCONIA Alumina NANO COMPOSITES in the last sintering stage. The average grain size of near full dense specimens made via conventional sintering (CS) was around 400nm. By using novel tow- step sintering, however, the final grain size (200nm) dropped 2 times less than that for specimens produced by the CS method. After densification, the mechanical properties, the relative proportion of TCP formed and the microstructures of the composite were observed. By used of two step sintering, highest hardness and fracture toughness, lowest relative proportion of TCP and NANOstructure were achieved.

Cubic crystalline oxides such as Y2O3 and MgO is used to stabalized ZIRCONIA phases at high temperature. In this paper the Y2O3 powder was added to stabilized ZIRCONIA and preparing a mixture of MgAl2O4 Spinel by mixing 1mol of NANO-MgO with 1 mol of NANO-Al2O3 powders. The spinel was added to the Y2O3-ZrO2 by various weight percentage (5, 10, 15, 20 and 25 wt%), and after that the specimens was prepared by axial pressing and sintered at 1550 o C for 4 hours as soaking time. The grain size was tested by using Atomic Force Microscopy (AFM) and calculated for surface of specimens and it was found to be decreasing (> 0. 6 µ m) to (~ 108 nm). The thermal properties were clearly influenced by the structural characteristics of the MAS. The thermal conductivity and thermal diffusion was decreased slightly from 5. 7 to 5. 5 W/m. K and from 2. 5 to 1. 5 mm 2 /s, respectively. The thermal capacity was increased from 483 to 615 J/kg. K, and thermal expansion coefficient was increased from 10 to 7. 5×10-6 o C-1 due to the compatibility of thermal expansion coefficients of (Y-PSZ)-MAS oxides. Thermal properties values are compatible with thermal insulation requirements in energy storage applications.

Homogeneous NANO-composite calcium phosphate glass-ceramic/yttri-stablized ZIRCONIA by the sol-gel method was prepared and the effect of various amounts of ZIRCONIA on microstructure of NANO-composite was investigated. After heat treatment at 700oC, the glass which is produced by the sol-gel method crystallized partially and hydroxyapatite in the range of NANOmeter formed. Due to ion exchange of calcium and zirconium between hydroxyapatite and ZIRCONIA, hydroxyapatite unit cell volume increased. Also, by increasing zirconium, the degree of crystalinity in the glass-ceramic increased.

The present study aimed to investigate the synthesis, microstructural and mechanical properties of alumina/ZIRCONIA-cobalt composite. The compositions containing 5, 10, 20 Vol.% of the sum of ZrO2 and Co were studied. The composite powders were prepared through mixing of alumina powder with partially stabilized ZIRCONIA and cobalt sulfate powders followed by calcination treatment at 1100 for 3h and reduction of cobalt by aluminum powder additive, in carbon bed at 950 for 3h. The XRD analysis showed the presence of Al2O3, t-ZrO2, Co and a little m-ZrO2. In order to investigate the properties of Al2O3/ZrO2-Co composite, composite powders were pressed uniaxial followed by Cold Isostatic Pressing (CIP) at 400MPa. The prepared discs were sintered in carbon bed at 1550 1600, 1650 for 5h. The alumina specimen was also prepared with the same procedure. The final results showed that the highest relative density value was 83.9% obtained for the specimen with the composition containing 5vol.% ZrO2 and 5vol.% Co densified at 1650 for 5h. The bending strength and hardness of this specimen was 322MPa and 11.95MPa.m1.2 respectively. So 20.15% increment of bending strength and 15.96% decrease of hardness was observed compare to monolithic alumina. The decrease of hardness was due to the lower hardness of metallic phase and the increase of bending strength is occurred because of presence of ZIRCONIA and cobalt particles which prevent of alumina grains growth.

NANO-enhanced characteristic fiber COMPOSITES (NFCs) are getting a part of intrigued as eco-friendly choices compared to customary engineered materials. They are superior for the environment and offer assistance reduce hurtful impacts. These materials utilize common filaments like jute, hemp, flax, and sisal, which can be developed once more and break down effectively in nature, to create plastic more grounded. They combine being great for the environment with being solid and valuable. Including little materials like NANO-clays, NANO-cellulose, or NANO-silica to the blend or applying them to the surface makes characteristic fiber COMPOSITES (NFCs) much more grounded. This makes a difference them handle warm superior and makes them safer to water.   NANO-NFCs are progressively utilized in different ranges such as cars, buildings, bundling, and ordinary things, where lightweight and eco-friendly materials are in tall request. This consider looks at the qualities, viability, and potential applications of NANO-improved NFCs.  It looks at their quality, how they bargain with warm, and how well they work with plastic. We pay consideration to issues like getting damp, not enduring a long time, and contrasts in fiber quality. These variables can influence how well NFCs work and how tried and true they are. To fathom these problems, researchers are investigating better approaches to form normal strands way better for utilize in composite materials. These incorporate covering the strands, changing their chemicals, blending them with man-made filaments, and utilizing exceptionally little innovation.   The natural benefits of NANO-NFCs are looked at, counting decreased carbon emanations, lower vitality utilize when they are made, and the reality that they can break down actually when they are now not required. In spite of a few challenges, NANO-NFCs offer a promising choice for companies needing to utilize naturally inviting materials. This ponder appears how critical it is to keep investigating and moving forward ways to process and treat fibers, use little materials, and make beyond any doubt they all work together well.