-
Effect of Heating Atmosphere and Alkali Metal Doping on the Acidic and Basic Sites of Magnesium Oxide
Muhammad Bilal,
Samuel David Jackson,
Alexander Leishman Munnoch,
Javed Ali
Issue:
Volume 5, Issue 2, March 2016
Pages:
36-42
Received:
5 January 2016
Accepted:
25 January 2016
Published:
6 March 2016
Abstract: Reaction can either be acid or base catalysed. Among the different base catalysed reactions MgO has attracted keen interest from researchers in the last two decades. For different types of reactions different base strength catalyst is required. The basic strength of MgO can be modified in different ways including alkali metal doping of MgO which is main aim of this work. Also the acidic and basic properties of which are measured under different atmospheres to demonstrate the impact of this variable. The Alkali doped MgO catalyst was prepared by impregnation method and the acidic and basic sites were determined using CO2 and NH3. It was found that doping of MgO with alkali metals significantly decreased the BET surface area and decreased the phase transition temperature for brucite to periclase by about 50°C. Alkali metal doping also significantly increased the number of basic sites whilst decreasing the number of acidic sites as compared to pure MgO. Under a hydrogen atmosphere the number of basic sites on alkali metal doped MgO significantly increased.
Abstract: Reaction can either be acid or base catalysed. Among the different base catalysed reactions MgO has attracted keen interest from researchers in the last two decades. For different types of reactions different base strength catalyst is required. The basic strength of MgO can be modified in different ways including alkali metal doping of MgO which is...
Show More
-
The Effect of Repair Welding Number on Microstructure of Hastelloy X Fabricated via TIG Process
Mohammad Reza Abedi,
Hamed Sabet,
Hossein Razavi
Issue:
Volume 5, Issue 2, March 2016
Pages:
43-48
Received:
22 November 2015
Accepted:
5 December 2015
Published:
21 March 2016
Abstract: The effect of repair welding number on microstructure of the hastelloy X fabricated via TIG process was investigated. The SEM, EDS and OM were used to determine mechanical properties and the microstructure of HAZ zone, respectively. Results showed that the grain size of base metal determined by OM and SEM was 64.11 μm with M6C and M23C6 carbides (6.16, 18.71 μm respectively). Also, using welding for three times caused increase of grain size (15%, 22%, 26% respectively) and the heat input made some carbides dissolve. The grain growth through HAZ zone venially affected the strength of alloy. The results of tensile test demonstrated that UTS increased by repair welding, 1%, 2% and 3% respectively. As the UTS of base metal was 727 MPa, the fracture phenomenon occurred. Furthermore, repair welding of mentioned alloy did not exceed more than three times.
Abstract: The effect of repair welding number on microstructure of the hastelloy X fabricated via TIG process was investigated. The SEM, EDS and OM were used to determine mechanical properties and the microstructure of HAZ zone, respectively. Results showed that the grain size of base metal determined by OM and SEM was 64.11 μm with M6C and M23C6 carbides (6...
Show More
-
Elastic Deformation Induced Non-equilibrium Segregation of P in IN718 Alloy
Jinhui Du,
Xudong Lu,
Zhongnan Bi,
Tingdong Xu
Issue:
Volume 5, Issue 2, March 2016
Pages:
49-53
Received:
24 March 2016
Published:
25 March 2016
Abstract: IN718 alloy is a precipitation hardened, nickel-based superalloy that is used extensively in the aircraft engine industry. The excellent cyclic fatigue resistance, high tensile strength, fracture toughness and oxidation resistance allow the alloy to be safely used at maximum useful service temperature of about 650ºC. Many researchers improve the alloy's high-temperature strength through adding of P. However, segregation of P at grain boundary can be induced the grain boundary embrittlement, decreased the tension reduction in area. In this paper, intermediate-temperature embrittlement (ITE) for a IN718 alloy has been experimentally studied by elevated-temperature tension tests. International standard ISO 6892-2 (Metallic Materials Tensile Testing) indicates that the variations in temperature of this measurement system have been found to have a larger potential effect on test results, which is a kind of uncertainty contribution not related to test equipment. International standard ISO 6892-2 maintains that strain rate variations can induce the measurement uncertainty of mechanical properties in tensile testing, which will imperil the reliability of tension tests. The measurement uncertainty of reduction in area relative to strain rate, called as strain rate embrittlement (SRE), is first described experimentally for IN718 alloy in this paper. Then the measurement uncertainty is clarified based on microscopic theory of elastic deformation in metals. It is shown that the elastic deformation of tension test induced the segregation of impurities to grain boundaries and the relevant embrittlement which produces the measurement uncertainty of reduction in area.
Abstract: IN718 alloy is a precipitation hardened, nickel-based superalloy that is used extensively in the aircraft engine industry. The excellent cyclic fatigue resistance, high tensile strength, fracture toughness and oxidation resistance allow the alloy to be safely used at maximum useful service temperature of about 650ºC. Many researchers improve the al...
Show More
-
Hydrothermal Synthesis and Luminescence Properties of Monodisperse Spherical CaF2 and CaF2:Ln3+ (Ln = Eu, Tb, Ce/Tb) Microcrystals
Xiaohong Yang,
Jingjing Cao,
Shanshan Hu
Issue:
Volume 5, Issue 2, March 2016
Pages:
54-60
Received:
8 April 2016
Published:
9 April 2016
Abstract: Spherical CaF2 and CaF2:Ln3+ (Ln = Eu, Tb, Ce/Tb) with tunable particle size (about 2.5 µm) have been synthesized by one-step facile and effective hydrothermal method. The spherical structure was highly uniform and well-dispersed. It was found that reaction time, pH value, and reaction temperature have important effects on the controlled synthesis of spherical CaF2. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM), photo-luminescence (PL) and luminescence decay curve. Under UV excitation, the CaF2:Eu3+ showed the red emission (5D0→7FJ = 0, 1, 2, 3) and the CaF2:Tb3+ presented the green emission (5D4→7FJ = 6, 5, 4, 3), respectively. Furthermore, Ce3+/Tb3+ co-doped CaF2 showed efficient energy transfer from Ce3+ to Tb3+, which presented strong green photo-luminescence of Tb3+. Due to excellent luminescent properties, the obtained samples can be used in many fields, such as light display systems, optoelectronic devices and biological imaging.
Abstract: Spherical CaF2 and CaF2:Ln3+ (Ln = Eu, Tb, Ce/Tb) with tunable particle size (about 2.5 µm) have been synthesized by one-step facile and effective hydrothermal method. The spherical structure was highly uniform and well-dispersed. It was found that reaction time, pH value, and reaction temperature have important effects on the controlled synt...
Show More
-
Resistivity Quantitative Measurement Model and Accuracy Analysis of Hydrogen Content in Pure Aluminum
Ling-qi Meng,
Shi-wei Chen,
Si-wei Luo,
Heng-hua Zhang
Issue:
Volume 5, Issue 2, March 2016
Pages:
61-65
Received:
8 April 2016
Published:
9 April 2016
Abstract: Hydrogen content in pure aluminum melting was increased through inserting fresh branches and measured by decompression solidification method and density method. Resistivity of pure aluminum casting was measured by means of the electrical resistance method, and physical model of resistivity measuring method was established. Combined with experimental data, the mathematical relationship between resistivity of pure aluminum casting and hydrogen content was derived. To further verify the feasibility of resistivity measurement model on the hydrogen content in aluminum melting, this paper also has carried on the hydrogen evolution experiment.
Abstract: Hydrogen content in pure aluminum melting was increased through inserting fresh branches and measured by decompression solidification method and density method. Resistivity of pure aluminum casting was measured by means of the electrical resistance method, and physical model of resistivity measuring method was established. Combined with experimenta...
Show More
-
Development and Assessment of Composite Brake Pad Using Pulverized Cocoa Beans Shells Filler
Adeyemi Ibukun Olabisi.,
Ademoh Nuhu. Adam,
Okwu Modestus Okechukwu
Issue:
Volume 5, Issue 2, March 2016
Pages:
66-78
Received:
9 October 2015
Accepted:
21 October 2015
Published:
13 April 2016
Abstract: Application of asbestos in friction material after a very long period is now discouraged due to its carcinogenic nature. There is need for alternative (human friendly) friction material. Hence the development of asbestos-free friction material from an agro-waste (cocoa beans shells - CBS) as filler element cum other additives was undertaken using powder metallurgy technique. The particulate size of the filler material considered was 300µm and epoxy resin was used as binder. The produced brake pad samples were analyzed by evaluating their mechanical, physical, and tribological properties. Based on the investigated properties of the developed brake pad, reducing the filler content increased the wear rate, tensile strength, compressive strength, while hardness, density, water absorption, oil absorption and thermal conductivity varied differently. Coefficient of friction increased with increase in the filler wt%. The results showed that CBS particles could be effectively used as replacement for asbestos in automotive brake pad manufacture.
Abstract: Application of asbestos in friction material after a very long period is now discouraged due to its carcinogenic nature. There is need for alternative (human friendly) friction material. Hence the development of asbestos-free friction material from an agro-waste (cocoa beans shells - CBS) as filler element cum other additives was undertaken using p...
Show More
-
The Research on the Production of Bio-based Polyamides 56 Sheath-core Composite Modified Fiber
Shouyun Zhang,
Jinghong Ma
Issue:
Volume 5, Issue 2, March 2016
Pages:
79-83
Received:
3 May 2016
Published:
4 May 2016
Abstract: In order to improve the moisture absorption, the antistatic properties of chemical fiber and improve the wearing comfort of fabric, the author has studied the modification and the production process of the sheath-core composite fiber which made of bio-based polyamide 56 and PET. Experiments show: selecting the appropriate production technology, using the bio-based polyamide 56 as the cortical structures, using the pet as the core structure we can produce high quality Sheath-core composite modified fiber by Composite spinneret. The Fiber has good moisture absorption performance and easy to be dyed. The fabric feel satiny soft and has a good elasticity, antistatic effect. It wears comfortable and the conformal performance is good.
Abstract: In order to improve the moisture absorption, the antistatic properties of chemical fiber and improve the wearing comfort of fabric, the author has studied the modification and the production process of the sheath-core composite fiber which made of bio-based polyamide 56 and PET. Experiments show: selecting the appropriate production technology, usi...
Show More
-
Microstructure and Properties of Cu/W85Cu/Cu Composites for Electronic Packaging
Jia Jin-Hao,
Bai Shu-Xin,
Xiong De-Gan,
Chang Jin,
Gao Ming-Qi
Issue:
Volume 5, Issue 2, March 2016
Pages:
84-88
Received:
22 April 2016
Published:
4 May 2016
Abstract: The Cu/W85Cu/Cu composite was fabricated by pressureless infiltration and brazing method successfully. The microstructure and physical properties of Cu/W85Cu/Cu composites were investigated. The results show the interfacial region of Cu/W85Cu/Cu composites was consisted of Cu substrate, Cu–BAgCu28 interfacial layer, BAgCu28 layer, BAgCu28-Ni interfacial layer and W85Cu composite. Moreover, the interfacial microstructures investigated by SEM shows that that the electroplated Ni on the surface of W85Cu composites can improve the fillers wettability of the W85Cu composites. Further investigation reveals that the Cu/W85Cu/Cu composites possess relative low density (13.88g/cm3), excellent thermal management function as a result of high thermal conductivity up to 288.68 W/(m•K) and low coefficient of thermal expansion (7.55×10−6K−1) at room temperature. The above properties of composites successfully meet the requirement of electronic packaging. The shear strength test analysis shows that the Cu, filler (BAg72Cu), and electroplated Ni layer and W85Cu realized metallurgically joining.
Abstract: The Cu/W85Cu/Cu composite was fabricated by pressureless infiltration and brazing method successfully. The microstructure and physical properties of Cu/W85Cu/Cu composites were investigated. The results show the interfacial region of Cu/W85Cu/Cu composites was consisted of Cu substrate, Cu–BAgCu28 interfacial layer, BAgCu28 layer, BAgCu28-Ni interf...
Show More
-
Performance Simulation and Fabrication of PZT Piezoelectric Composite Ring
Issue:
Volume 5, Issue 2, March 2016
Pages:
89-94
Received:
3 May 2016
Published:
4 May 2016
Abstract: High-frequency wideband omnidirectional transducer is the development direction of the research of underwater acoustic transducer, PZT piezoelectric composite ring is not only capable of horizontal omnidirectional transmitting and receiving underwater acoustic signal. Meanwhile, it also makes the bandwidth of the transducer is expanded. Using the ANASYS finite element simulation software, the modal simulation of the ring structure of the 2-2 type piezoelectric composite is carried out, and the relationship curve of the bandwidth and the structure size is obtained. Based on the simulation, a design scheme is formed, cutting circular piezoelectric ceramics along the axial direction, there is epoxy resin in the groove. Thus the 2-2 type piezoelectric composite circular tube is formatted. The piezoelectric composite circular tubes suitable for horizontal omnidirectional broadband transducer.
Abstract: High-frequency wideband omnidirectional transducer is the development direction of the research of underwater acoustic transducer, PZT piezoelectric composite ring is not only capable of horizontal omnidirectional transmitting and receiving underwater acoustic signal. Meanwhile, it also makes the bandwidth of the transducer is expanded. Using the A...
Show More
-
Decreasing the Effect of Ultra Violet Ray on Polypropylene by Using Chromium Tri-oxide
Issue:
Volume 5, Issue 2, March 2016
Pages:
95-101
Received:
5 April 2016
Accepted:
19 April 2016
Published:
7 May 2016
Abstract: Chromium tri-oxide (CrO3) /polypropylene sheets have been prepared by twin screw extruder machine. Polypropylene (PP) is being used in producing tanks, pressure vessels, and other outer doors applications to reduce original cost. The effect of ultraviolet ray has been studied because of the tertiary carbon bonds in PP chain structure is the center of UV attack. Mechanical tests (tension, flexural, hardness, and creep) have been carried out on (CrO3/PP) with proportions (0.05%, 0.1%). The results show that, after different intervals of UV exposure (CrO3) works as stabilizer and plasticizer at the same time.
Abstract: Chromium tri-oxide (CrO3) /polypropylene sheets have been prepared by twin screw extruder machine. Polypropylene (PP) is being used in producing tanks, pressure vessels, and other outer doors applications to reduce original cost. The effect of ultraviolet ray has been studied because of the tertiary carbon bonds in PP chain structure is the center ...
Show More
-
Research on Progress of Tribological Modification of Polyetheretherketone
Li Shu Long,
Wang Yan Jun,
Qin Ke,
Li Chao
Issue:
Volume 5, Issue 2, March 2016
Pages:
102-107
Received:
7 May 2016
Published:
9 May 2016
Abstract: The characteristics and application of poly ether ether ketone (PEEK) has been reviewed in the paper. The tribological modification of PEEK composites which were reinforced by inorganic fillers, the fiber, polymer blends, plasma and mixed modification were introduced. Finally research progress of tribological modification of PEEK composites was forecasted.
Abstract: The characteristics and application of poly ether ether ketone (PEEK) has been reviewed in the paper. The tribological modification of PEEK composites which were reinforced by inorganic fillers, the fiber, polymer blends, plasma and mixed modification were introduced. Finally research progress of tribological modification of PEEK composites was for...
Show More
-
The Research Status of the Wetting of Metal/Ceramic in the High Temperature Self-Lubricating Materials
Li Chao,
Wang Yan Jun,
Qin Ke,
Li Shu Long
Issue:
Volume 5, Issue 2, March 2016
Pages:
108-112
Received:
7 May 2016
Published:
9 May 2016
Abstract: The wettability of solid lubricant and matrix sintered body is very important for the production of the high temperature self-lubricating composite material. The wettability of the metal/ceramic is ubiquitous phenomenon in materials science and people have long the research in this field. Research on the wettability of the ceramic/metal has important practical significance for developing new type of metal/ceramic systems, exporing and developing the preparation technology of material, and preparing high performance of metal/ceramic composite materials. In this paper, from the wetting phenomenon of the metal/ceramic, the commonly used theory of the wettability research is stated, various experimental methods of wettability are introduced, and the significant importance of improving the wettability for developing metal ceramic friction material is indicated. What’s more, some methods of improving the wettability are proposed.
Abstract: The wettability of solid lubricant and matrix sintered body is very important for the production of the high temperature self-lubricating composite material. The wettability of the metal/ceramic is ubiquitous phenomenon in materials science and people have long the research in this field. Research on the wettability of the ceramic/metal has importa...
Show More
-
Effect of Wood Shaving to Improve the Properties of Particleboard Made from Sorghum Bagasse
Apri Heri Iswanto,
Irawati Azhar,
Arida Susilowati,
Supriyanto,
Andrianta Ginting
Issue:
Volume 5, Issue 2, March 2016
Pages:
113-118
Received:
27 April 2016
Accepted:
7 May 2016
Published:
14 May 2016
Abstract: The objective of this research was to evaluate the effect of wood shaving added to improve the mechanical properties of particleboard. Wood types were using in this research included of Meranti, Cempedak, Mahagony, and Durian wood. Ratio of Sorghum bagasse and wood shaving was 50/50 (%w/w). Amount of 10% urea formaldehyde (UF) resin used for binding in the manufacturing process. Furthermore, hot pressing of mat at 130°C temperature for 10 minute and 30 kg cm-2 pressure. The final step was conditioning process for 7 days at room temperature before testing of sample. The results showed that the thickness swelling (TS) parameter did not met of JIS A 5908 (2003). Overall the present of wood shaving resulted in decreasing of TS value. Combination of Cempedak and Mahagony wood resulted of the lower TS value compared with control and other treatment. For bending properties, combination of sorghum bagasse and Cempedak wood shaving resulted the best of bending properties. However for the MOE parameter had not met JIS A 5908 (2003). The internal bond (IB) parameter showed that the utilization of wood shaving to produce of particleboard caused of increasing the IB value. The IB value was resulting from this research had met of JIS A 5908 (2003).
Abstract: The objective of this research was to evaluate the effect of wood shaving added to improve the mechanical properties of particleboard. Wood types were using in this research included of Meranti, Cempedak, Mahagony, and Durian wood. Ratio of Sorghum bagasse and wood shaving was 50/50 (%w/w). Amount of 10% urea formaldehyde (UF) resin used for bindin...
Show More
