Second harmonic generation, optical, thermal, piezoelectric and mechanical properties of adipic acid-doped ADP crystals

Single crystals of pure and 2[Formula: see text]mol.% adipic acid (hexanedioic acid) -doped ammonium dihydrogen phosphate (ADP) were grown by conventional slow evaporation of aqueous solution technique. The powder X-ray diffraction and FT-IR analyses indicate that the crystals undergo considerable stress as a result of doping. UV–Vis studies show that the absorption of the adipic acid-doped crystals is less than that of pure ADP. Thermal studies (TG/DTG) disclose that the decomposition temperature of doped ADP is more than that of pure ADP. Vicker’s microhardness study reveals that the addition of adipic acid increases the hardness of the ADP. SHG efficiency and piezoelectric charge coefficient of adipic acid-doped ADP are higher than that of pure ADP.

Investigation the effect addition of nano Al2O3 on microstructure of Yttria tetragonal Zirconia polycrystalline ceramic

Purpose: This research aimed to prepare tetragonal zirconia polycrystals powder by coprecipitation method and study effects of addition of different amounts of nano Al2O3 (1, 2 and 4) wt.% on its microstructure and mechanical properties of (5Y-TZP) composite. Design/methodology/approach: The powder was uniaxial pressed at a pressure of 150 MPa and held for 60 s, and sintered at the 1500°C, held for two hours and then cooling down at 5°C/min to room temperature. Microhardness and fracture toughness tests were utilized to evaluate the mechanical properties of yttria tetragonal zirconia polycrystal composite. The microstructure has been observed using field emission scanning electron microscopy(FESEM). Findings: The results showed an addition of nano Al2O3 has a great influence on hardness and microstructure, the increase in Vicker's microhardness of composite samples with the increase in the nano Al2O3 wt.% and microstructure were characterized with homogeneous zirconia distribution, grain growth destruction with the increasing percentage of nano Al2O3. The most important influence is the enhancing of the densification process as the porosity decreased. The highest hardness and maximum fracture toughness were recorded at 4 wt.% nano Al2O3. Research limitations/implications: Ceramic matrix composites are developed to overcome the brittleness of ZrO2 and the low toughness of alumina by formation, a large difference of elastic behavior between matrix and particles(dispersion phase )which disturbs the stress field as a dislocation comes near a particle. Practical implications: Zirconia has mechanical properties similar to those of stainless steel. Yttria-stabilized tetragonal Zirconia (Y-TZP) is growing used in dentistry due to its good mechanical properties such as hardness and fracture toughness. Thus, controlling of microstructure by adding nanoalumina plays an important role in enhancing these properties. Originality/value: Study the adding bitty percentage from nano alumina on microstructure and mechanical properties of (5Y-TZP) ceramic.

The effect of 5% NaOCl and 17% EDTA, at 24hrs and 8days, on the microhardness of MTA, Biodentine and Pozzolan cement: An in- vitro study.

Aim & Objectives: The aim of this study was to evaluate the effects, at 24 h and 8 days, of 5% NaOCl and 17% EDTA on the Vicker’s microhardness of Mineral Trioxide Aggregate(MTA Angelus) (MTAA), Biodentine(Septodont, Saint Maur des Fosse’s France) and Pozzolan based endodontic cement named Endocem MTA(Maruchi, Wonju, Korea). Materials and method: Sixty samples of MTAA, Biodentine and Endocem MTA were tested for baseline microhardness at 24 h. They were divided into 12 subgroups (5% NaOCl or 17% EDTA, 24 h and 5% NaOCl or 17% EDTA at 8 days) and microhardness was evaluated at different time points. Results were recorded and analysed statistically via one-way ANOVA and Tukey’s post hoc test. Results: MTAA had a higher baseline microhardness than both biodentine and Endocem MTA. At 24 hrs, the microhardness of all the materials was reduced by NaOCl and EDTA. At 8 days, NaOCl reduced the microhardness of MTA but that of Biodentine and Endocem MTA was increased. EDTA at 8 days, reduced the microhardness of both MTAA and Biodentine but an increase was seen with Endocem MTA. Conclusion: Changes in microhardness of MTAA, Biodentine and Pozzolan cement(Endocem MTA) were associated with the time for which the materials are allowed to set as well as the irrigating agent used,.

Grain Orientation Induced Softening in Electrodeposited Gradient Nanostructured Nickel during Cold Rolling Deformation

Quantitative microstructural evolution and the corresponding microhardness of electrodeposited nanostructured nickel sheet during cold rolling deformation are investigated by x-ray diffraction, transmission electron microscopy and Vicker’s microhardness testing. Particularly, to investigate the effect of stress states on deformation behavior, two series of gradient nanostructured nickel with symmetric structures and the homogeneous counterparts with three levels of grain size are compared based on macro-statistical data. In such hierarchical sandwich-like gradient samples, the layers with larger grain size, as the soft phase, indeed sustain more deformation. Deformation-induced grain rotation changes are observed in the center layers with a relatively larger grain size, accompanied by an obvious decrease in microhardness. According to the quantitative microstructural parameters including the grain size, dislocation density and stacking fault probability before and after deformation, evaluation based on Hall-Petch and Bailey-Hirsch relationships indicates the transition from strain hardening to softening can be attributed to grain orientation change.

Analysis of susceptor temperature during microwave heating and characterization of Ni-30Cr3C2 clads

Hydropower plants are experiencing huge revenue losses due to the failure of hydro turbines caused by cavitation. Surface modification could be a feasible solution to tackle this problem. Microwave processing of metallic materials to coat/clad has gained popularity in recent years. In the current study, microwave exposure time by analyzing susceptor temperature is optimized to get sound clads. Nickel-based and Cr3C2-reinforced clad on SS-316 substrate is developed for cavitation erosion resistance. The clads have been developed in a domestic microwave oven of 2.45 GHz and 900 W. The Ni + 30% Cr3C2 developed clad has been characterized through various standard mechanical and metallurgical techniques like X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, Vicker’s micro-hardness, porosity measurement, and flexural study. The presence of various carbide and intermetallic phases Cr2Ni3, Cr7C3, CrSi, SiO2, and FeNi3 is confirmed from the X-ray diffraction pattern. The distribution of hard carbide phases into soft matrix is confirmed from the microstructural investigation. Vicker’s microhardness study confirms the enhanced average microhardness of the clad region by 2.5 times of the substrate. The analysis of porosity shows significantly less (0.98%) porosity. The flexural study of developed clads by using three-point bending test is evaluated and flexural strength and deformation index values of developed clads of 814 ± 11.5 MPa and 2.29 × 10−4 mm N−1 respectively are observed.

Synthesis, Growth, Optical, Structural and Mechanical Characterization of SPNP and KPNP Single Crystal using Ethanol as a Solvent

Single crystals of sodium para nitro phenol (SPNP) and potassium para nitro phenol (KPNP) was synthesized at room temperature by slow evaporation solution growth technique using ethanol as a solvent upto the size of 12 × 3 × 2 mm3 and 15 × 2 × 2 mm3 respectively. The grown crystals were characterized by UV- Visible, photoluminescence, Kurtz- Perry test, single crystal X-ray diffraction analysis and Vicker’s microhardness studies. Structural identification of grown crystals was done by single crystal X-ray diffraction and it shows both the crystals are belongs to triclinic crystal system. The SPNP and KPNP crystal emits green light radiation as evident from the PL measurement. The UV -Visible study revealed that the grown crystal has high transmission window with cut off wavelength of 207 nm and 208 nm respectively. And also the direct optical band gap was estimated to be 3.23 eV and 3.20 eV using Tauc’s plot. The SHG output of grown crystals was recorded by Kurtz Perry technique and it is found to be nearly five times greater than the reference KDP. The Vickers hardness test confirms the mechanical stability of the material.

Characterization of Cobalt Based Microwave Clad Developed on SS-355

In the present work a detailed microstructural investigation of Cobalt based microwave cladding on S-355 stainless steel was carried out. The experimentations were carried out in a home based domestic microwave oven. This article clears the circumstances of clad formation during microwave hybrid heating. The solidification texture and grain structure of the developed clad scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy, and measurement of Vicker’s microhardness. Cobalt based clads developed with an approximate thickness of 1 mm without interfacial cracking. The microstructure of clad clearly illustrated excellent metallurgical bond with S-355 substrate and found dominantly fine cellular grains. Iron and cobalt were recognized inside the cells while chromium was ascertained segregated around the cell boundaries. The average microhardness of the cobalt based clad was observed in the range of 402±60 HV.

Evaluation of the effect of two commercially available non-alcoholic mouth rinses on the microhardness of composite material - An invitro study

Composites have been widely used for anterior as well as posterior restorations due to increased aesthetic demands. Composite restorations placed in patients oral cavity is subjected to masticatory load, pH changes and chemical effect due to mouthwashes, beverages, food etc and the detrimental effects associated with these challenges on the microhardness of composite has to be determined. The study was conducted to evaluate the effect of two commercially available non-alcoholic mouth rinses on the microhardness of micro-hybrid and nanohybrid composite resins. Forty disc-shaped composite specimens were made from each type of composite materials and were divided into 5 groups with 8 samples each, Group 1= Microhybrid+Chlorhex, Group2=Microhybrid + Hexidine, Group3= Nanohybrid + Chlorhex, Group4= Nanohybrid+ Hexidine, Group 5= Nanohybrid and Micro hybrid + artificial saliva(Control).The samples were immersed in mouthrinses for 24 hrs and microhardness was subsequently measured using a Vicker’s microhardness tester. There was no significant difference in microhardness values of tested composite resins in either mouth rinses when compared to composites immersed in artificial saliva. Non-alcoholic mouth rinses do not affect the microhardness of micro-hybrid and nanohybrid composites.

Evaluation of the effect of two commercially available non-alcoholic mouth rinses on the microhardness of composite material - An invitro study

Background; Composites have been widely used for anterior as well as posterior restorations due to increased aesthetic demands. Composite restorations placed in patients oral cavity is subjected to masticatory load, pH changes and chemical effect due to mouthwashes, beverages, food etc and the detrimental effects associated with these challenges on the microhardness of composite has to be determined. The study was conducted to evaluate the effect of two commercially available non-alcoholic mouth rinses on the microhardness of micro-hybrid and nanohybrid composite resins. Materials and methods: Forty disc-shaped composite specimens were made from each type of composite materials and were divided into 5 groups with 8 samples each, Group 1= Microhybrid+Chlorhex, Group2=Microhybrid + Hexidine, Group3= Nanohybrid + Chlorhex, Group4= Nanohybrid+ Hexidine, Group 5= Nanohybrid and Micro hybrid + artificial saliva(Control).The samples were immersed in mouthrinses for 24 hrs and microhardness was subsequently measured using a Vicker’s microhardness tester. Results: There was no significant difference in microhardness values of tested composite resins in either mouth rinses when compared to composites immersed in artificial saliva. Conclusion: Non-alcoholic mouth rinses do not affect the microhardness of micro-hybrid and nanohybrid composites.