scholarly journals Al2O3/ZrO2 Materials as an Environmentally Friendly Solution for Linear Infrastructure Applications

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2375
Author(s):  
Justyna Zygmuntowicz ◽  
Radosław Żurowski ◽  
Justyna Tomaszewska ◽  
Marcin Wachowski ◽  
Janusz Torzewski ◽  
...  

The present work deals with the evaluation of the effect of ZrO2 on the structure and selected properties of shapes obtained using the centrifugal slip casting method. The samples were made of alumina and zirconia. The applied technology made it possible to produce tubes with a high density reaching 99–100% after sintering. Very good bonding was obtained at the Al2O3/ZrO2 interphase boundaries with no discernible delamination or cracks, which was confirmed by STEM observations. In the case of Al2O3/ZrO2 composites containing 5 vol.% and 10 vol.% ZrO2, the presence of equiaxial ZrO2 grains with an average size of 0.25 µm was observed, which are distributed along the grain boundaries of Al2O3. At the same time, the composites exhibited a very high hardness of 22–23 GPa. Moreover, the environmental influences accompanying the sintering process were quantified. The impacts were determined using the life cycle analysis method, in the phase related to the extraction and processing of raw materials and the process of producing Al2O3/ZrO2 composites. The results obtained show that the production of 1 kg of sintered composite results in greenhouse gas emissions of 2.24–2.9 kg CO2 eq. which is comparable to the amount of emissions accompanying the production of 1 kg of Polyvinyl Chloride (PVC), Polypropylene (PP), or hot-rolled steel products.

Author(s):  
H. Aydin ◽  
R. Ceylantekin ◽  
G. Tokataş

Purpose: This study deals with the effects of colemanite (Ca2B6O115H2O) on properties ofslip-cast mullite–zirconia composites prepared via reaction–sintering of kaolinite, aluminaand zircon powders.Design/methodology/approach: Colloidal processing (slip casting) is the routetowards preparing these materials using 45 vol.% aqueous suspensions of a mixture offine powders stabilized with polyacrylate solution as a dispersant.Findings: The influence of powder composition on physical, mineralogical properties, andmicrostructure of these composites after firing at 1450, 1500 and 1550°C are observed.The results show that the density of composites tends to increase with the addition of7 wt.% colemanite. XRD analyses reveal that using colemanite during the synthesis ofmullite-zirconia composites lowers the reaction temperature. All of the composites consistof irregularly shaped mullite and round-shaped zirconia grains, which are distributedhomogenously.Practical implications: Mullite–zirconia composites, owing to their chemical inertnessand good resistance against chemical attack-corrosion by siliceous and metallic melts, theyare employed in the glass industry.Originality/value: Reaction sintering process is considered as a promising technology forpreparing mullite-zirconia composites, because it has some advantages such as low costof traditional raw materials, straightforward production technology and low manufacturingcost.


2005 ◽  
Vol 10 (2) ◽  
pp. 151-160 ◽  
Author(s):  
J. Kala ◽  
Z. Kala

Authors of article analysed influence of variability of yield strength over cross-section of hot rolled steel member to its load-carrying capacity. In calculation models, the yield strength is usually taken as constant. But yield strength of a steel hot-rolled beam is generally a random quantity. Not only the whole beam but also its parts have slightly different material characteristics. According to the results of more accurate measurements, the statistical characteristics of the material taken from various cross-section points (e.g. from a web and a flange) are, however, more or less different. This variation is described by one dimensional random field. The load-carrying capacity of the beam IPE300 under bending moment at its ends with the lateral buckling influence included is analysed, nondimensional slenderness according to EC3 is λ¯ = 0.6. For this relatively low slender beam the influence of the yield strength on the load-carrying capacity is large. Also the influence of all the other imperfections as accurately as possible, the load-carrying capacity was determined by geometrically and materially nonlinear solution of very accurate FEM model by the ANSYS programme.


2018 ◽  
Vol 7 (2) ◽  
Author(s):  
Firman L. Sahwan

Organic materials that are generally used as raw material for organic fertilizer granules (POG) is a natural organic material that has been degrade, smooth and dry. One of the main raw materials are always used with a very high percentage of usage, is manure. Manure potential in Indonesia is very high, amounting to 113.6 million tons per year, or 64.7 million tons per year to the island of Java. From this amount, it will be generated numbers POG production potential of 17.5 million tons per year (total Indonesia) or 9.9 million tons per year for the island of Java. While the realistic POG production predictions figures made from raw manure is 2.5 million tons annually, a figure that has been unable to meet the number requirement of POG greater than 4 million tons per year. Therefore, in producing POG, it should be to maximize the using of the potential of other organic materials so that the use of manure can be saved. With the use of a small amount of manure (maximum 30% for cow manure), it would be useful also to avoid the production of POG with high Fe content.keywods: organic material, manure, granule organic fertilizer


Alloy Digest ◽  
2015 ◽  
Vol 64 (3) ◽  

Abstract Dogal H 700 LAD is a galvanized hot rolled steel that is microalloyed and can be cold formed. The 700 signifies the minimum yield strength. This datasheet provides information on composition, physical properties, tensile properties. and bend strength. It also includes information on forming. Filing Code: CS-184. Producer or source: SSAB Swedish Steel Inc..


Alloy Digest ◽  
1979 ◽  
Vol 28 (5) ◽  

Abstract ARMCO FORMABLE 70 HR is a hot-rolled steel with excellent ductility, weldability and edge-tear resistance at a minimum yield strength of 70,000 psi (483 MPa). For this relatively high strength level, it has unusually good fabricating properties that are the result of closely controlled processing of a fully killed, low-carbon, vacuum-degassed, columbium-alloyed steel. This special composition and processing practice minimize harmful nonmetallic inclusions that hamper formability. Typical applications include automotive reinforcements, truck parts and construction components. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-359. Producer or source: Armco Inc., Eastern Steel Division.


Alloy Digest ◽  
2006 ◽  
Vol 55 (3) ◽  

Abstract DuraTech 30 is a superhigh-speed steel evolved from the ASTM M3-2 composition, but with added cobalt. The exotic composition offers improved toughness and very high hardness. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on high temperature performance and wear resistance as well as heat treating, machining, and powder metal forms. Filing Code: TS-629. Producer or source: Timken Latrobe Steel.


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