Structural and surface properties of chromatographic porous silica, alumina, titania and zirconia were studied using thermogravimetry and nitrogen adsorption. The samples studied are mesoporous and exhibit relatively narrow pore size distributions in the range from 10 to 30 nm, making them suitable for chromatographic applications. Low-pressure nitrogen adsorption and thermogravimetry were used...

INTRODUCION: Improved wear resistance of crosslinked UHMWPE has been well demonstrated in both hip and knee [1-4]. A reduction of 70% can be shown in knee simulators from conventional crosslinked tibial inserts (CXPE) gamma-irradiated at 3.5Mrad to 7Mrad highly crosslinked inserts (HXPE). Hip simulator models indicated that debris size decreased with increased crosslinking [5]. In the knee it h...

Between January 1988 and January 1991 we performed 100 consecutive cemented total hip replacements using a zirconia head, a titanium alloy stem and a polyethylene cup. We reviewed 78 of these hips in 61 patients in detail at a mean of 5.8 years (1 to 9). Aseptic loosening was seen in 11 hips (14%). Eight needed revision. In total, 37 cups (47.5%) showed radiolucent lines, all at the cement-bone...

Since hydroxyapatite has excellent biocompatibility and bone bonding ability, porous hydroxyapatite ceramics have been intensively studied. However, porous hydroxyapatite bodies are mechanically weak and brittle, which makes shaping and implantation difficult. One way to solve this problem is to introduce a strong porous network onto which hydroxyapatite coating is applied. In this study, porou...

PURPOSE: Many studies in the dental literature look at the effect of different surface treatment methods on the flexure strength of zirconia where polished zirconia has been used as control. However, zirconia is subjected to different types of surface damage as a result of the CAD/CAM milling procedure and also to damage produced by other laboratory procedures in use daily. AIM OF THE WORK: The...

an efficient and green protocol for the synthesis of pyrazoles derivatives by one-pot reaction of different 1,3-dicarbonyl compounds with hydrazines/hydrazides has been developed using nano-sulfated zirconia, nano-structured zno, nano-g-alumina and nano-zsm-5 zeolites, as the catalyst. the optical properties of the nano-structured catalysts and organic molecules were studied. the advantages of ...

• Influence of alumina content on fs-laser machining zirconia-alumina composites was studied. Significant influence material composition removal behavior demonstrated. Single phase materials have larger laser ablation thresholds and smaller rate than their composites. A lower scan speed is preferred for single while a higher beneficial the Laser texturing ceramics promising surface modification...

United Nations has estimated that 130 million people would suffer from osteoarthritis worldwide by 2050. This disease require patients to undergo a surgery known as Total Hip Replacement (THR) which failure rate of approximately 1 % with lifespan 20 years. The biomaterials used manufacture this total hip artroplasty are mainly made Zirconia-Toughened Alumina. In work, Zirconia Toughened Alumina...

Among novel structural materials, composites are attractive because they combine the properties of two o more individual components. As an important example, in alumina-zirconia ceramic composite system, the incorporation of α-Al2O3 into stabilized zirconia increases significantly the mechanical and thermal properties. In this work an alumina-zirconia ceramic composite have been prepared with d...

Four aluminas were used as supports for impregnation with a zirconium oxide with the aim to achieve a coating, without phase separation, between support and modifier. The supports were impregnated with different concentrations of zirconium aqueous resin, obtained through the polymeric precursor method. After impregnation the samples were calcined and then characterized by XRD, which led to iden...