Effect of Adding Silver Element and Zirconia Ceramic on Corrosion Behavior and Mechanical Properties of Pure Titanium

In this research, all the samples are prepared using the powder metallurgy technique by adding silver element and Zirconia ceramic material to the commercially pure titanium at a different weight percent of (10, 20 and 30) to investigate the effect of adding these materials to the CP-Ti on corrosion behavior and mechanical properties. There are two sets of each type of alloys Ti-Ag and Ti ZrO2. The Preparation process was by Weighing, Mixing and Homogenizing Powders by Ball Mill, compacting at 4 tons for 1 min. and Sintering at 700 and 900 °C for 2 hrs. under a controlled atmosphere. The corrosion results showed a good corrosion resistance increases with increasing the silver content as the corrosion rate would be the best in (30% Ag) content with(0.091 mpy) at sintering temperature of 700 °C. And with a sintering temperature of 900 °C, the best result was with (30% Ag) with (0.059) mpy. In the Ti-ZrO2 alloys, the best result was with the zirconia content of (30%ZrO2) when cooled in the air with (1.347) mpy at sintering temperature of 700 °C, this results obtained in Ringer’s solution. And microstructures analysis stated that at the silver and the Zirconia content of (10-20 wt%) single phase of (α- Ti alloy), as the silver and Zirconia content increased to (30% wt), in addition to (α-phase), (Ti2Ag) intermetallic compound developed in the silver alloy microstructure and (TiZr)3O intermetallic compound developed in the microstructure of Ti- Zirconia composites and the hardness test result best hardness of...

Ceria–Zirconia Mixed Metal Oxides Prepared via Mechanochemical Grinding of Carbonates for the Total Oxidation of Propane and Naphthalene

A series of ceria–zirconia mixed metal oxides with varying metal ratios were prepared by the calcination of precursors synthesized by mechanochemical grinding of the metal carbonates, and tested for catalytic naphthalene and propane total combustion. The mechanically-mixed metal oxides were more active for both propane and naphthalene total oxidation compared to the parent metal oxides. Ce0.95Zr0.05Ox was the most active catalyst for the total combustion of propane and naphthalene. Catalysts were characterized by x-ray diffraction, BET surface area, laser Raman spectroscopy, temperature programmed reduction, scanning electron microscopy with energy dispersive x-ray analysis and x-ray photoelectron spectroscopy techniques. Formation of ceria–zirconia solid solutions was observed for catalysts with a zirconia content of 10% or lower, whereas ceria and zirconia phase separation was observed when zirconia content was above 25%. Surface area increased when ceria and zirconia were mixed, and the reduction temperature of the bulk shifted to lower temperatures upon increasing zirconia content. Incorporation of zirconia was found to increase the relative concentration of surface oxygen defects compared to pure ceria, with low amounts of zirconia showing the greatest increase. The concentration of oxygen defects correlates with propane and naphthalene total oxidation activity. The enhanced total oxidation activity occurs as a result of the increased number of oxygen defects and the higher surface area. The results demonstrate that mechanochemical preparation from carbonate precursors was an effective route to make active catalysts.

Contamination Study of Zirconia on the Densification Process and Properties of Transparent MgAl2O4 Ceramics

In this paper, transparent magnesium aluminate (MgAl2O4) spinel ceramics are fabricated through pressureless sintering combined with hot isostatic pressing (HIPing). To investigate the effect of zirconia on sintering behavior, microstructure, and optical properties of transparent spinel ceramics, different contents of zirconia were added. The results show that zirconia can promote the densification process by the formation of anion vacancies. The resulting zirconia exists as tetragonal phase along the grain boundaries. The average grain size of resulting ceramics depends on the content of zirconia and HIPing condition. Small zirconia content did not deteriorate the optical properties of samples. A 5-mm-thick sample with 0.05 wt% ZrO2 pre-sintered at 1500 °C followed by HIPing treatment at 1550 °C achieved a high in-line transmittance of 75.5% at 400 nm and 85% at 1100 nm.

Studying the Effect of ZrO2 Addition on Hydroxyapatite via Ball Milling Technique

The bio-composited ceramic stabilized zirconia-hydroxyapatite had been formed by ball milling method. The hydroxyapatite was synthesized from chicken eggshell via chemical precipitation. And it was mixed with stabilized zirconia powder together. All of the samples had been investigated by XRD, FTIR and UTM tester. The XRD and FTIR result showed that the stabilized zirconia-hydroxyapatite sample powder after ball mill was found only hydroxyapatite and zirconia phase without addition of other phase. High crystallinity of hydroxyapatite can be found after heat treatment and calcium zirconium oxide was formed around 1300 °C. In addition, the compressive strength increased with increasing the zirconia content shown by UTM tester.