[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Welding Metallurgy of

Composites science and technology

Properties and Application of Geopolymers Vol. 841 (/MSF.841 /book) Development and Investigation of Materials Using Modern Techniques Vol. 840 (/MSF.840/book) Superplasticity in Advanced Materials ICSAM 2015 Vols. 838-839 (/MSF.838-839/book) 12th International Conference on High Speed Machining Vols. 836-837 (/MSF.836-837/book) Sintering Fundamentals II Vol. 835 (/MSF.835/book) Advanced Machining Technologies: Traditions and Innovations Vol. 834 (/MSF.834/book) Applied Materials and Technologies Vol. 833 (/MSF.833/book) Emerging Functional Materials: Book (/MSF.841/book) Papers (/MSF.841)

Materials Science Forum

This tutorial review considers defect chemistry of TiO2 and its solid solutions as well as defect-related properties associated with solar-to-chemical energy conversion, such as Fermi level, bandgap, charge transport and surface active sites. Defect disorder is discussed in terms of defect reactions and the related charge compensation. Defect equilibria are used in derivation of defect diagrams showing the effect of oxygen activity and temperature on the concentration of both ionic and electronic defects. These defect diagrams may be used for imposition of desired semiconducting properties that are needed to maximize the performance of TiO2-based photoelectrodes for the generation of solar hydrogen fuel using photo electrochemical cells (PECs) and photocatalysts for water purification. The performance of the TiO2-based semiconductors is considered in terms of the key performance-related properties (KPPs) that are defect related. It is shown that defect engineering may be applied for optimization of the KPPs in order to achieve optimum performance.

Defect chemistry and defect engineering of TiO2-based semiconductors for solar energy conversion

This research paper reports the effect of natural fiber content on the physical and mechanical properties as well as fracture behavior of composite cement reinforced with coconut fiber. The mix design was based on 1:1 for cement:sand ratio and 0.55 was fixed for amount of water per cement ratio. Coconut fiber was added as reinforcement and replacing the composition of sand. Composites were developed based on 3 wt. %, 6 wt. %, 9 wt. %, 12 wt. % and 15 wt. % of coconut fiber by mixing and curing process. Composites were cured in water for 7, 14, and 28 days. It was observed that the composite reinforced with 9 wt. % of coconut fiber demonstrated the highest strength of modulus of rupture and compressive strength. Results of density, water absorption and moisture content are also presented.

Composite cement reinforced coconut fiber: physical and mechanical properties and fracture behavior

Assessment of Physical and Mechanical Properties of Cement Panel Influenced by Treated and Untreated Coconut Fiber Addition

The attractive performance-to-cost ratio associated with the incorporation of waste material in composite formulations used to produce brake pads has stimulated the idea of exploring the possible incorporation of additional waste materials in such formulations. Thus, the viability of adding palm slag to the composite formulation used in brake pads was investigated, and the results are reported in this paper. In addition, other fillers, such as calcium carbonate and dolomite, were used for comparative purposes. The properties examined included thermal properties, compressive strength, and wear behavior. The results showed that palm slag has significant potential for use as an alternative to the existing fillers in the composite formulations used to produce brake pads.

Comparative study on thermal, compressive, and wear properties of palm slag brake pad composite with other fillers

This study focused on fabricating and characterizing composites of iron-chromium alloy reinforced with 5–25 wt. % of alumina particles fabricated using powder metallurgy method. The diffraction patterns of X-Ray diffraction (XRD) reveal the influence of varying weight percentage of alumina. Comparisons on the mechanical properties are also being made on the unreinforced iron matrix (0 wt. %). The compatibility between matrix and reinforcement was indicated from the microstructure examination showing homogeneous distribution of alumina particles in the alloy matrix. Bulk density and porosity of the composites were calculated using standard Archimedean testing. Micro-hardness was measured using micro-Vickers hardness instrument. The data obtained showed that the 20 wt. % alumina produced the highest hardness reading. Keywords: iron, chromium, alumina, composites, powder metallurgy Abstrak: Kajian ini tertumpu kepada fabrikasi dan pencirian komposit aloi besi-kromium ditetulangi dengan 5–25 peratus berat serbuk alumina. Komposit difabrikasi menggunakan kaedah metalurgi serbuk. Corak pembelauan XRD menunjukkan pengaruh peratus berat alumina yang berbeza. Perbandingan terhadap ciri-ciri mekanikal juga dilakukan bagi matriks besi tanpa tetulang (0 peratus berat). Kesesuaian antara matriks dan tetulang telah diperhatikan dari kajian mikrostruktur yang menunjukkan taburan serbuk alumina adalah homogen di dalam matriks aloi. Ketumpatan pukal dan keliangan komposit dihitung menggunakan ujian Archimedes. Mikro-kekerasan ditentukan menggunakan peralatan kekerasan mikro-Vickers. Data yang diperolehi menunjukkan 20 peratus berat serbuk alumina menghasilkan bacaan kekerasan tertinggi.

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Characterization of Fe-Cr-Al2O3 Composites Fabricated by Powder Metallurgy Method with Varying Weight Percentage of Alumina

Iron based matrix composites reinforced with 5 to 25 wt pct of Al2O3 particles were fabricated using the powder metallurgy method. The samples were prepared by mixing at 250 rpm for 30 minutes, uniaxially pressing at 750 MPa and sintering in a vacuum furnace at a temperature of 1373 K (1100 °C) for 2 hours with 10 °C/min heating rate. The optimum amount of reinforcement was determined by evaluating the microstructure, relative density, total porosity, micro Vickers hardness, and wear resistance of the composites. The results and analysis revealed that the micro Vickers hardness and wear resistance of the composites were better after increasing the reinforcement up to 20 wt pct. Increasing the Al2O3 particles to 25 wt pct resulted in a decrease in mechanical properties due to agglomeration of the particles in the matrix, which lowers the interaction between the matrix and reinforcement.

Shamsul Baharin Jamaludin

Papers

Composite cement reinforced coconut fiber: physical and mechanical properties and fracture behavior

Assessment of Physical and Mechanical Properties of Cement Panel Influenced by Treated and Untreated Coconut Fiber Addition

Comparative study on thermal, compressive, and wear properties of palm slag brake pad composite with other fillers

Characterization of Fe-Cr-Al2O3 Composites Fabricated by Powder Metallurgy Method with Varying Weight Percentage of Alumina

The Effects of Al2O3 Amount on the Microstructure and Properties of Fe-Cr Matrix Composites