Enhancement of Dry Sliding Tribological Characteristics of Perforated Zirconia Toughened Alumina Ceramic Composite Filled With Nano MoS2 in High Vacuum

2020 ◽  
Vol 143 (6) ◽  
Author(s):  
Kunal Ghosh ◽  
Subhrojyoti Mazumder ◽  
Harish Hirani ◽  
Poulomi Roy ◽  
Nilrudra Mandal
Keyword(s):  
Ceramic Composite ◽  
High Vacuum ◽  
Ceramic Composites ◽  
Alumina Ceramic ◽  
Tribological Characteristics ◽  
Dry Sliding ◽  
Temperature Environment ◽  
Zirconia Toughened Alumina ◽  
Wear Tests ◽  
High Temperature Environment

Abstract An innovative approach was adopted for fabricating zirconia toughened alumina (ZTA)-MoS2 self-lubricating ceramic composites with the inclusion of hydrothermally synthesized nano MoS2 through the micropores of perforated ZTA ceramics. This method avoided the exposure of MoS2 in high-temperature environment due to its in-sensitiveness during traditional sintering techniques. Different weight percentages (wt%: 0, 5, 10, and 15) of graphite were incorporated to produce porous ZTA ceramics with the help of cold press sintering followed by insertion of nano MoS2 into the matrices. Best tribological characteristics were obtained with 10 wt% graphite-ZTA-MoS2 specimen which offered an improvement of ∼66% in coefficient of friction (COF) and ∼96% in specific wear rate when dry sliding tests were carried out against silicon nitride (Si3N4) in high vacuum (5.0 × 10−4 mbar). Nano MoS2 was sheared off at the contacting interface during sliding under load which showed a good tribological characteristics of the composite. Delamination was found as the dominating wear mechanism in ZTA-MoS2 composites during wear tests.

Effects of TiO2 addition on the phase, mechanical properties, and microstructure of zirconia-toughened alumina ceramic composite

2015 ◽  
Vol 41 (3) ◽  
pp. 3961-3967 ◽  
Author(s):  
Hanisah Manshor ◽  
Suriyana Md Aris ◽  
Ahmad Zahirani Ahmad Azhar ◽  
Ezzat Chan Abdullah ◽  
Zainal Arifin Ahmad
Keyword(s):  
Mechanical Properties ◽  
Ceramic Composite ◽  
Alumina Ceramic ◽  
Tio2 Addition ◽  
Zirconia Toughened Alumina

scholarly journals Microstructure Characteristics of Ce-ZTA Ceramic Composites Obtained by Liquid Phase Sintering

2006 ◽  
Vol 530-531 ◽  
pp. 421-424
Author(s):  
Haine Beck ◽  
Maria do Carmo de Andrade Nono ◽  
Francisco Piorino Neto
Keyword(s):  
Ceramic Composite ◽  
Glassy Phase ◽  
Volume Fraction ◽  
Tetragonal Zirconia ◽  
Ceramic Composites ◽  
Liquid Phase Sintering ◽  
Scanning Electronic Microscopy ◽  
Powder Samples ◽  
Zirconia Toughened Alumina ◽  
Crystalline Matrix

Zirconia-toughened alumina (ZTA) ceramics with Ce-TZP (tetragonal zirconia polycrystalline doped with ceria) volume fraction on 33% were prepared with the addition.. The influence of glass infiltrated method was investigated. Coprecipitated Zr and Ce hydroxide mixture was obtained from ZrOCl2.8H2O and CeCl3. 7H2O aqueous solution. CeO2-ZrO2 calcinated powder was compacted and the compacted samples were sintered at 1180°C. Powder samples were characterized by scanning electronic microscopy (SEM), The volume fraction of each phase, the grains size and shapes, and the porosity were investigated with SEM. The relative density and shrinkage was investigate too. The results showed that the crystalline matrix was composed by SiO2 -B2O3-La2O3-Al2O3-Ce-TZP and revealed the important role played the glassy phase in the densification of this ceramic composite.

Effect of MgO Nano Particle on Mechanical Property and Microstructure of ZTA Ceramic Composite

2011 ◽  
Vol 364 ◽  
pp. 450-454 ◽  
Author(s):  
Ahmad Zahirani Ahmad Azhar ◽  
Mohamad Hasmaliza ◽  
Manimaran Ratnam ◽  
Zainal Arifin Ahmad
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Vickers Hardness ◽  
Ceramic Composite ◽  
Weight Percent ◽  
Alumina Ceramic ◽  
Nano Particle ◽  
Microstructural Observation ◽  
Hardness Property ◽  
Zirconia Toughened Alumina

The mechanical properties and microstructure of zirconia-toughened-alumina ceramic composite doped with nanoparticle of MgO is investigated. The nanoMgO weight percent was varied from 0.3 wt % to 1.3 wt %. Each batch of composition was mixed using ultrasonic cleaner and mechanical stirrer, uniaxially pressed and sintered at 1600 °C for 4 h in pressureless conditions. Analysis of bulk density, Vickers hardness and microstructural observation has been carried out. Results of Vickers hardness increased linearly with addition of more nanoMgO until a certain composition. Maximum Vickers hardness obtained was 1740HV with 1.1 wt % MgO. Furthermore, microstructural observations show that the Al2O3 grain size depends on the particle size of MgO, and is directly related to its hardness property.

Peridynamical Modelling of Nanoindentation in Ceramic Composites

2016 ◽  
Vol 254 ◽  
pp. 55-59 ◽  
Author(s):  
Tomasz Sadowski ◽  
Błażej Pankowski
Keyword(s):  
Ceramic Composite ◽  
Ceramic Composites ◽  
Intrinsic Stress ◽  
Stress Singularities ◽  
Continuum Approach ◽  
Two Phase ◽  
Brittle Solids ◽  
Complex Phenomena ◽  
Zirconia Toughened Alumina

Indentation in brittle solids involves many complex phenomena related to cleavage and contact, as well as intrinsic stress singularities, which are almost impossible to capture with traditional continuum approach and FEA at mesoscale. In case of a two-phase ceramic composite [1–3] the number of unknown material and interfacial constants, that have to be calibrated experimentally, increases rapidly [4, 5]. In this paper, nanoindentation in zirconia-toughened alumina (ZTA) is modelled using discrete (peridynamical) approach

Structural and Microstructure Relationship with Fracture Toughness of CeO2 Addition into Zirconia Toughened Alumina (ZTA) Ceramic Composites

2012 ◽  
Vol 620 ◽  
pp. 252-256 ◽  
Author(s):  
Nik Akmar Rejab ◽  
Ahmad Zahirani Ahmad Azhar ◽  
Manimaran Ratnam ◽  
Zainal Arifin Ahmad
Keyword(s):  
Fracture Toughness ◽  
Weight Percent ◽  
Ceramic Composites ◽  
Alumina Ceramic ◽  
X Ray Diffraction ◽  
Phase Determination ◽  
X Ray ◽  
Diffraction Patterns ◽  
Zirconia Toughened Alumina

The effect of CeO2addition in zirconia toughened alumina (ZTA) was examined. The CeO2addition in weight percent (wt %) was varied from 0 wt% to 15 wt%. The fabricated samples were sintered at a temperature of 1600°C. The sintered samples were characterized their properties such as fracture toughness and phase determination. X-ray diffraction patterns confirm the constituent phases present in the samples were alumina and zirconia. Fracture toughness for each sample in the range of 5.878.38 MPam1/2respectively. It was observed that the addition of ceria increased the fracture toughness of the zirconia toughened alumina ceramic composites.

Effect of Titania and Magnesia on the Physical Properties of Zirconia Toughened Alumina

2016 ◽  
Vol 840 ◽  
pp. 82-86
Author(s):  
Hanisah Manshor ◽  
Wan Muhammad Ihsan Wan Sabri ◽  
Abdul Wahid Ramli ◽  
Ahmad Zahirani Ahmad Azhar ◽  
Ezzat Chan Abdullah ◽  
...  
Keyword(s):  
Physical Properties ◽  
Ceramic Composite ◽  
High Hardness ◽  
Secondary Phase ◽  
Solubility Limit ◽  
Ceramic Composites ◽  
High Temperature Strength ◽  
Constant Weight ◽  
Weight Percentage ◽  
Zirconia Toughened Alumina

ZTA based ceramic composite system is widely accepted as cutting tools for many of these harder and wear resistant workpiece materials. This is due to their beneficial mechanical properties i.e. high temperature strength, high hardness and ability to maintain its cutting edge shape at higher temperatures. Although a lot of works have focused on the effect of various sintering additives on the ZTA ceramic system, the effect of Magnesia (MgO) and Titania (TiO2) on ZTA has not yet been studied. In this work, the physical properties of Zirconia Toughened Alumina (ZTA) ceramic composite with MgO and TiO2 as additives was investigated. The composition of TiO2 varied from 0 wt% to 3.5 wt% whereby other materials such as Al2O3, Yttria Stabilized Zirconia (YSZ) and MgO were kept at constant weight percentage. Sintered samples were then tested and analyzed by XRD, Vickers hardness and high precision densimeter to investigate phase content, hardness value and densification respectively. Results showed that the solubility limit of TiO2 in ZTA-MgO ceramic composites is at 2.0 wt%. Further addition of TiO2 resulted in the formation of secondary phase known as Zirconium titanium oxide (Zr0.35TiO0.65O2) which deteriorate the properties exhibited by ZTA-MgO-TiO2 ceramic composites.

scholarly journals Research on Performance Test System of Space Harmonic Reducer in High Vacuum and Low Temperature Environment

Machines ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Jing Wang ◽  
Zhihua Wan ◽  
Zhurong Dong ◽  
Zhengguo Li
Keyword(s):  
Low Temperature ◽  
High Speed ◽  
Performance Test ◽  
High Reliability ◽  
High Vacuum ◽  
Test System ◽  
Low Noise ◽  
Speed Ratio ◽  
Space Harmonic ◽  
Temperature Environment

The harmonic reducer, with its advantages of high precision, low noise, light weight, and high speed ratio, has been widely used in aerospace solar wing deployment mechanisms, antenna pointing mechanisms, robot joints, and other precision transmission fields. Accurately predicting the performance of the harmonic reducer under various application conditions is of great significance to the high reliability and long life of the harmonic reducer. In this paper, a set of automatic harmonic reducer performance test systems is designed. By using the CANOpen bus interface to control the servo motor as the drive motor, through accurately controlling the motor speed and rotation angle, collecting the angle, torque, and current in real time, the life cycle test of space harmonic reducer was carried out in high vacuum and low temperature environment on the ground. Then, the collected data were automatically analyzed and calculated. The test data of the transmission accuracy, backlash, and transmission efficiency of the space harmonic reducer were obtained. It is proven by experiments that the performance data of the harmonic reducer in space work can be more accurately obtained by using the test system mentioned in this paper, which is convenient for further research on related lubricating materials.

scholarly journals Oxide Bioceramic Composites in Orthopedics and Dentistry

2021 ◽  
Vol 5 (8) ◽  
pp. 206
Author(s):  
Piconi Corrado ◽  
Sprio Simone
Keyword(s):  
Mechanical Behavior ◽  
Hip Replacement ◽  
Ceramic Composites ◽  
Clinical Applications ◽  
Wide Field ◽  
Joint Replacements ◽  
Composite Systems ◽  
Third Phase ◽  
Main Component ◽  
Zirconia Toughened Alumina

Ceramic composites based on alumina and zirconia have found a wide field of application in the present century in orthopedic joint replacements, and their use in dentistry is spreading. The development of this class of bioceramic composites was started in the 1980s, but the first clinical applications of the total hip replacement joint were introduced in the market only in the early 2000s. Since then, several composite systems were introduced in joint replacements. These materials are classified as Zirconia-Toughened Alumina if alumina is the main component or as Alumina-Toughened Zirconia when zirconia is the main component. In addition, some of them may contain a third phase based on strontium exa-aluminate. The flexibility in device design due to the excellent mechanical behavior of this class of bioceramics results in a number of innovative devices for joint replacements in the hip, the knee, and the shoulder, as well in dental implants. This paper gives an overview of the different materials available and on orthopedic and dental devices made out of oxide bioceramic composites today on the market or under development.

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