Sara Lee Kit Yee

Tunku Abdul Rahman University of Management and Technology (TAR UMT)

The effect of small amounts of copper oxide, manganese oxide, and stainless steel as sintering additives on the sintering behavior and mechanical properties of Alumina Toughened Zirconia (ATZ, 3Y-TZP with 20 wt% Al 2 O 3 ) ceramic composites were evaluated and contrasted with that of undoped ATZ by using microwave sintering (MW) method. Green bodie...

This study investigated the effect of copper oxide addition on the alumina toughened zirconia composite ceramic using microwave sintering. CuO amounts (0.05–1 wt%) were examined at sintering temperatures (1250–1500 °C). Investigations covered hardness, toughness, phase stability, microstructure, and densification. Optimum doping was 0.2 wt%, result...

The effect of dimensions on the safety factor, allowable stress, and deformation of the lumbar disc prosthesis model at L4-L5 was investigated. The process involved geometry design, meshing, enhancement in element quality, and setting of boundary conditions using SolidWorks and ANSYS software. The range of motion (ROM) of flexion and extension were...

The effect of zirconia concentrations on the properties of alumina–zirconia composites prepared by slip-casting method was studied. Varying amounts of yttria-tetragonal zirconia (Y-TZP) ranging up to 90 vol.% were added in alumina and sintered at 1450 °C. The sintered composites were then characterised in terms of bulk density, microstructure, Vick...

Hydroxyapatite (HA) was synthesized from chicken bone waste by calcination. Pectin was extracted from orange peels by microwave irradiation, and 1 and 3 wt % of pectin was incorporated into the HA. The resulting powders were then pressed into disk samples before being sintered at temperatures of 1050, 1150, and 1250 °C for 2 h. Various analytical t...

Hydroxyapatite (HA) derived from chicken bones was successfully synthesized by calcination and compared with biomimetic HA prepared via chemical precipitation, using pectin-mediated synthesis process. Pectin was extracted from orange peels via microwave irradiation and integrated into chicken bone-HA with the assistance of ultrasonication and ball...

Scandia stabilised zirconia (ScSZ) ceramics are promising materials for use as electrolyte in solid oxide fuel cells (SOFCs) for cleaner energy conversion and storage owing to their high ionic conductivity at high temperatures (∼850°C). However, its ionic conductivity drops when it operates at intermediate temperatures (500 -700°C) where its crysta...

The present work investigated the sintering behaviour and mechanical properties of 0.2 % copper oxide (CuO) doped 3 mol% yttria-tetragonal zirconia polycrystal (Y-TZP) via microwave sintering. The microwave (MWV) sintered samples were heated at temperatures varying from 1100 to 1400 °C, with a heating rate of 30 °C/min for 5 minutes. These samples...

The effect of pressureless sintering on the mechanical and microstructure properties of 3 mol% yttria-tetragonal zirconia polycrystal ceramic (Y-TZP) was evaluated. The conventional sintering was conducted at temperatures between 1250 to 1600 °C for a period of 2 hours, with a heating and cooling rate of 10°C per min. Characterization of sintered Y...

Hydroxyapatite (HA) is a type of calcium phosphate-based bioactive ceramic that resembles the mineral phase of bone and teeth with great potential for bone substitution and biomedical implants. Biogenic-derived HA emerges as a cheap and eco-sustainable alternative to improve waste utilization. However, hydroxyapatite has limited applications due to...

The low-temperature degradation (LTD) behaviour of undoped and 0.2 % copper oxide-doped 3 mol% yttria-tetragonal zirconia polycrystal (Y-TZP) via microwave (MWV) sintering were studied in this work. The MWV-sintered samples were heated at temperatures varying from 1100 to 1400 °C, with a heating rate of 30 °C per min and holding time of 5 min. Thes...

The effect of copper oxide doping (0.05–1 wt%) on the densification, microstructure evolution and mechanical characteristics of alumina toughened zirconia (ATZ: 80 wt% Y-TZP + 20 wt% Al2O3) ceramic composites was investigated. Green samples were pressureless sintered using a short hold time of 12 min at temperatures varying from 1250 °C to 1500 °C....

The densification and mechanical properties of alumina ceramics were investigated via two-step sintering (TSS) with different holding time. The alumina ceramics were sintered at 1450 °C for 1 min during the first stage, followed by sintering at 1350 °C with different holding times (2-24h). Conventional sintering (CS) was also performed on the alu...

The effects of pressureless two-step sintering (TSS) on the densification and mechanical properties of tetragonal zirconia polycrystals were investigated and compared with that obtained by conventional single-step sintering (SSS). The TSS profile involved firing at a high temperature, T1 of 1450oC followed by cooling to a lower temperature, T2 of 1...

In this work, the sintering behaviour of fluorapatite (FAp)–silicate composites prepared by mixing variable amounts of natural quartz (2.5 wt% to 20 wt%) and FAp was studied. The composites were pressureless sintered in air at temperatures from 1000 °C to 1350 °C. The effects of temperatures on the densification, phase formation, chemical bonding a...

The design of the canopy utilizes the conventional rigid body mechanisms which is vulnerable to the presence of backlash, friction of joints or wearing of mechanical parts which lead to short product life. Compliant mechanisms are employed to reduce these mechanical problems, owing to their zero-joint and monolithic structure. A reference design fo...

The effects of manganese oxide, stainless steel and copper oxide doping on the sintering behaviour and mechanical properties of alumina-toughened zirconia (ATZ) were investigated. The prepared ceramic composites were conventionally sintered at 1250 °C, 1350 °C and 1500 °C, using different holding times (1, 12 and 120 min, respectively). The tetrago...

The effect of small amounts (0.2 wt% and 0.5 wt%) of transition metal oxide (CuO) doping on the sintering behavior of 3 mol% yttria-stabilized zirconia (Y-TZP) was investigated over the temperature range of 1250 o C to 1500 o C. Sintered samples were characterized to determine the phase present, relative density, microstructural evolution and Vicke...

The effect of weight force on knee model was studied by simulation analysis using the SolidWorks. Six different human weight varied from 40 kg to 90 kg were subjected to stress and strain analysis on the knee joint model. A mesh size of 3.5 mm was selected according to the corresponding maximum stress intensity and number of nodes. The results show...

The state of understanding on the devastating effects of hydrothermal ageing on the properties of yttria-tetragonal zirconia polycrystal (Y-TZP) when exposed to humid environment are reviewed. The prime factors governing the ageing-induced tetragonal to monoclinic phase transformation include the tetragonal grain size, sintering techniques particul...

The effect of various amounts of copper oxide (CuO) up to 1 wt% on the densification behaviour and mechanical properties of 3 mol% yttria-tetragonal zirconia polycrystal (Y-TZP) were studied by using microwave (MW) sintering method. The MW sintering was performed at temperatures between 1100 °C and 1400 °C, with a heating rate of 30 °C/min. and hol...

Forsterite (Mg2SiO4) because of its exceptionally high fracture toughness which is close to that of cortical bones has been nominated as a possible successor to calcium phosphate bioceramics. Recent in vitro studies also suggest that forsterite possesses good bioactivity and promotes osteoblast proliferation as well as adhesion. However studies on...

Talc and magnesium oxide are used to prepare forsterite (Mg2SiO4) powder by solid-state reaction with ball milling method. The samples were sintered at temperature 1200°C, 1300°C, 1400°C and 1500°C with four different holding time duration 2 hours, 1 hour and 1 minute with ramp rate of 10°C/min respectively via conventional pressureless sintering m...

In the present study, phase pure forsterite was obtained in sintered bodies from powder mixtures that did not undergo a heat treatment process prior to sintering. This is contrary to the practice reported in the literature where the powder mixture is normally subjected to a heat treatment at about 1200 °C prior to sintering process. The present res...

The present work is on the synthesis of forsterite (Mg2SiO4) powder using talc and magnesium oxide powders as the starting materials followed by a heat treatment process. Sintering behavior and mechanical properties of the forsterite bodies were evaluated from 1200oC to 1500°C. Forsterite phase were detected in samples without any secondary phases...

The current study is to examine the effect of ultrasonication on the synthesis of forsterite (Mg2SiO4) powder. Ultrasonication and ball milling were performed using talc and magnesium oxide as starting precursors, followed by heat treatment to obtain forsterite. The X-ray diffraction results of the powders heat treated at 1200 °C showed that the 2...

With the assistance of heat treatment, forsterite (Mg 2SiO 4) powder was successfully synthesized using talc and magnesium oxide as the basic starting materials. Sintering behavior and mechanical properties were evaluated upon sintering the synthesized forsterite compacts from 1200 °C to 1500 °C. Forsterite phase without any secondary phase were ob...