Effect of Process Temperature and Time on the Properties of Microwave Plasma Nitrided Ti6Al4V alloy

Titanium alloy (e.g. Ti-6Al-4V) has an excellent combination of properties. However in many cases, the application is limited because of the poor wear property. In this work, a surface modification (plasma nitriding) is carried out to improve the surface properties of Ti-6Al-4V, as a treatment prior to a hardcoating deposition, leading to a duplex coating system. This is an effort to improve the surface and near surface property of Ti-6Al-4V. Plasma nitriding is performed utilizing microwave plasma method in 25% Ar- 75% N2 atmosphere at temperatures of 600°C and 700°C for different processing times (1, 3 and 5 hours). The phase and microstructure of plasma nitrided substrate were characterized by using X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The plasma nitrided Ti-6Al-4V properties (surface roughness, surface hardness and case depth) were determined using profilometer and microhardness, respectively. Results obtained showed a significant increase on the surface hardness of Ti-6Al-4V. This is due to the formation of TiN and Ti2N phases in the form of compound layer. Besides, it shows that the diffusion of nitrogen into the Ti-6Al-4V substrate produces case depth up to 130 μm and this contributes to the improvement of the near surface hardness due to the changes in the microstructures. It was also found that the surface hardness and surface roughness increased with the increases in the process temperature and times

Length and order of fuzzy autocatalytic set of a pressurized water reactor

The pressurized water reactor (PWR) is one type of nuclear power plant that generates electricity using heat from nuclear reactions which use steam produced from heated water to spin large turbines that generate electricity. The PWR contains two systems namely primary and secondary systems. The secondary system of a PWR in a previous study cannot give information regarding the catalytic interaction and relation amongst each and every parameter in the system and unable to present all the possible catalytic reactions between the variables in the system. In this research, several structures of Fuzzy Graph Type-3 of Fuzzy Autocatalytic Set (FACS) of a secondary system of a PWR, namely possible paths, fuzzy edge connectivity, length, detour distance, order, and size are explored. Omega algebra is used to determine all the possible paths for a FACS with respect to its fuzzy edge connectivity, length, and detour distance. An algorithm is developed and coded to find all the possible paths of the PWR. Furthermore, the algorithm is extended to obtain more characteristics of the FACS system. A sample data from a secondary system of a PWR is then applied to the algorithm to obtain a total of 317 possible cycle paths and 243 possible non-cycle paths at a maximum length of five. In addition, based on the patterns of non-cycle paths of FACS graphs, new characteristics of FACS are obtained and proven in the form of lemma, theorem and corollaries. In summary, the finding in this study can be used to characterize FACS of a PWR as well as other applications

Possible paths in autocatalytic and fuzzy autocatalytic sets

Graph theory has been used to model some systems. Graph and fuzzy set have led to the concept of fuzzy graph. An Autocatalytic Set (ACS) is a concept formally introduced in chemistry as a set of catalytically integrated molecules. Fuzzy Autocatalytic Set (FACS) is a merge between fuzzy, graph and autocatalytic set (ACS). In this paper, some new characteristics on autocatalytic and fuzzy autocatalytic sets are presented. These characteristics are on possible paths in autocatalytic and fuzzy autocatalytic sets

Effect of PEG Molecular Weight on the TiO2 Particle Structure and TiO2 Thin Films Properties

This research, deals with modification of sol gel process for the synthesis of porous TiO2- PEG thin films with good structural integrity for environmental self-cleaning applications. Relatively, by adding the PEG with various molecular weights (300, 400, and 600) could influence the formation of TiO2 films structure and adhesion. Moreover, the formation of porous TiO2 associated with larger pores will accelerate the mass transfer of the treated contaminants in the larger pore channels. The advantages of the unique structures of as-prepared TiO2₂ films in the application of environmental self-cleaning systems are extensively studied by characterizing the produced films using various advanced characterization tools. Adhesion of TiO2 thin films become smooth and better surface with increasing the coating layers. The X-ray Diffraction spectrum of prepared coating shows present of anatase phase as major phas

Nanocomposite TiAlBN Coatings As A Corrosion Protection Layer For AZ91 Mg Alloy Substrate In NaCl

Magnesium alloys create increasing interest in structural application where weight reduction is vast concern. However,one of magnesium drawback in various applications is low corrosion resistance.In general,a hard coating can be applied on metal to combat such a problem.AlN and TiN coatings are most widely utilized in manufacturing area i.e for structural application due to its high hardness, high chemical stability,and excellent adhesion to substrates.Most recent,TiAlBN coating catch many attentions due to its superior properties than other most studied hard coating.The incorporation of aluminium in the cubic face centered TiN structure on Ti sites leads to deformation and strengthening of the crystal structure of the coating together.Moreover,incorporation of BN in this coating should improve and enhanced the corrosion resistance of Mg alloy.Therefore,in this study,TiAlBN coating have been chosen to be deposited on Mg alloy using reactive magnetron sputtering together with AlN and TiN coatings for comparison study.During depositions, target power,working pressure and bias voltage are optimized for each coating.Analysis on the effect of AlN, TiN and TiAlBN coatings on Mg alloy substrate include thickness measurement and microstructure by scanning electron microscope (SEM).Coatings phase were analysed using glancing angle X-ray diffraction analysis (GAXRD) and corrosion properties were evaluated using potentiodynamic polarization in NaCl solution.TiAlBN shows better performance of corrosion protection with the least corrosion rate (penetration rate = 0.20 mm/yr;mass loss rate=0.97g/m2d) in sodium chloride (NaCl) solution although having the lowest coating thickness (412 nm)

Corrosion Performance Of Nitrided Based Coating On AZ91 Mg Alloy In Hank’s Solution

The use of Magnesium alloys as bioresorsable metallic implant is interesting to study due to the properties of magnesium ions which can be found naturally in bone tissue as well as are essential to human metabolism. However,its fast degradation rate and excess of these ions in the body may cause undesirable health effects. Therefore,surface treatment such as coating can offer an alternative solution to slow down the fast degradation rate of magnesium alloy.Thus,in this study,attempt has been made to coat the AZ91 magnesium alloy substrate with TiN,AlN and TiAlBN coatings using single hot press target with r.f. magnetron sputtering technique.During deposition,target power,working pressure and bias voltage were optimized for each coating deposition.Coating microstructure and its crystal phases are analysed using SEM and glancing angle X-ray diffraction analysis (GAXRD).Corrosion properties were evaluated using potentiodynamic polarization using Hank’s Solution as a medium to simulate body fluid.Result showed that TiAlBN coating is acting most successfully as a protection layer by slowing down the penetration of corrosion towards AZ91 Mg alloy substrate.SEM micrographs show a minimum damage to the substrate’s surface seen after subjected to corrosion test.In conclusion,TiAlBN coating is able to protect AZ91 Mg alloy substrate surface from corrosion and able to slow down their degradation rate.The better performance of TiAlBN coating create interest to further works on exploring the potential of this hard coated on AZ91 Mg alloy for biomaterial application

Effects of Process Temperature and Time on the Properties of Microwave Plasma Nitrided Ti-6Al-4V Alloy

Titanium alloy (e.g. Ti-6Al-4V) has an excellent combination of properties. However in many cases, the application is limited because of the poor wear property. In this work, a surface modification (plasma nitriding) is carried out to improve the surface properties of Ti-6Al-4V, as a treatment prior to a hardcoating deposition, leading to a duplex coating system. This is an effort to improve the surface and near surface property of Ti-6Al-4V. Plasma nitriding is performed utilizing microwave plasma method in 25% Ar- 75% N2 atmosphere at temperatures of 600°C and 700°C for different processing times (1, 3 and 5 hours). The phase and microstructure of plasma nitrided substrate were characterized by using X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The plasma nitrided Ti-6Al-4V properties (surface roughness, surface hardness and case depth) were determined using profilometer and microhardness, respectively. Results obtained showed a significant increase on the surface hardness of Ti-6Al-4V. This is due to the formation of TiN and Ti2N phases in the form of compound layer. Besides, it shows that the diffusion of nitrogen into the Ti-6Al-4V substrate produces case depth up to 130 μm and this contributes to the improvement of the near surface hardness due to the changes in the microstructures. It was also found that the surface hardness and surface roughness increased with the increases in the process temperature and times

The influence of substrate treatment on load carrying capacity of Ti6Al4V Duplex Coating

In this work, duplex coating is carried out by conducting microwave plasma nitriding on Ti6Al4V, followed by the deposition of hardcoating (CrN) using arc coating system. Plasma nitriding of Ti6Al4V alloy using microwave plasma technique, created a thick (~130µm) modified layer (case depth) at processing temperature of 700°C and 5 hour. The load carrying capacity of the duplex coating assessed using Rockwell-C test shows that case depth increase with an increased in process temperature and time for nitriding. Consequently, affect the formation of compound layer on the plasma nitrided specimen. Moreover, the formation of compound layer may lead to uneven distributions of the hardcoating (CrN) applied resulted in poor adhesion of hard coating - nitrided substrate

Chemical Composition Analysis of TiAlBN Nanocomposite Coating Deposited via RF Magnetron Sputtering

TiAlBN nanocomposite coating have been successfully deposited on AISI 316 substrate via RF magnetron sputtering by varying nitrogen-to-total flow ratio (RN) of 5, 15, 20, 25%, as well as varying substrate temperature of 100, 200, 300, and 400 ºC; using single Ti-Al-BN hot-pressed target. Chemical compositions of the coatings were analysed using X-ray photoelectron spectroscopy (XPS). XPS results showed that the TiAlBN nanocomposite coating reaches a nitride saturated state at higher RN (e.g 15, 20, and 25%) and boron concentration was found to be approximately 9 at.%. However, as the concentration of nitrogen decreases at lower RN (5%), boron concentration was found to increase to 16.17 at. %. This is due to the increase of TiB2 phase in the coating. Variations of substrate temperatures were found to give no significant effect on the chemical composition of the deposited TiAlBN nanocomposite coating

Ti6Al4V Surface Hardness Improvement by Duplex Coating

Ti6Al4V alloy are among the most widely used materials in engineering applications. This is because their relatively beneficial properties. However, inadequate wear properties of Ti6Al4V alloy have largely constrained the application for this material. In this study, Plasma nitriding of the Ti6Al4V was performed using microwave plasma technique at 600oC for 1hour, 3 hours and 5 hours then followed with deposition of CrN on plasma nitrided samples for duplex coating purposes. Microstructural analysis and hardness measurement revealed that formation of Ti2N and TiN phases indicating the formation of compound layer is observed for substrate nitrided at temperature as low as 600oC 1 hour and a substantial increase on the surface hardness of plasma nitrided Ti6Al4V is observed with an increase of process time. The duplex coating obtained in this study has significant surface hardness property and superior as compared with CrN coatings deposited on as received Ti6Al4V