Maja Kokunesoski, D. Janackovic, D. Kicevic, S. Ilić, A. Šaponjić
Effect of methyl methacrylate (MMA) as a binder and heating treatment were investigated to improve green alumina compacts machinability. Properties of green compacts and their corresponding sintered samples prepared with and without MMA were compared. Investigation of green and sintered properties was performed on samples compacted at applied pressures up to 150 MPa. After pressing, samples with MMA were thermally treated at 115oC. The intention was to enhance the polymerization of MMA at a temperature a little higher than the glass transition temperature (Tg = 103oC) of poly (methyl methacrylate). Green compacts with MMA had higher green density values than those without MMA. Sintered samples with MMA had lower values of sintered density and higher values of total porosity; after sintering, relative linear shrinkage was around 15 % for the whole range of applied pressures. The possibility of easily machining the green compacts with MMA produces great possibilities for application in many fields
{"title":"The effect of acrylate on the properties and machinability of alumina ceramics","authors":"Maja Kokunesoski, D. Janackovic, D. Kicevic, S. Ilić, A. Šaponjić","doi":"10.2298/sos2301103k","DOIUrl":"https://doi.org/10.2298/sos2301103k","url":null,"abstract":"Effect of methyl methacrylate (MMA) as a binder and heating treatment were investigated to improve green alumina compacts machinability. Properties of green compacts and their corresponding sintered samples prepared with and without MMA were compared. Investigation of green and sintered properties was performed on samples compacted at applied pressures up to 150 MPa. After pressing, samples with MMA were thermally treated at 115oC. The intention was to enhance the polymerization of MMA at a temperature a little higher than the glass transition temperature (Tg = 103oC) of poly (methyl methacrylate). Green compacts with MMA had higher green density values than those without MMA. Sintered samples with MMA had lower values of sintered density and higher values of total porosity; after sintering, relative linear shrinkage was around 15 % for the whole range of applied pressures. The possibility of easily machining the green compacts with MMA produces great possibilities for application in many fields","PeriodicalId":21592,"journal":{"name":"Science of Sintering","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68811802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Extrusion at 450?C of hot compacted premixed aluminium alloy powder 7075 resulted in full density and banded microstructure with the average transverse grain size of 13.6 ?m after T6 heat treatment. It increased mechanical properties to yield and tensile stresses of 457 and 492 MPa, respectively and elongation 6.4 %. These meet the requirements of the ASTM standard ASM for 7075T6 conventionally manufactured alloy of similar chemical composition. The respective microstructures were compared and also to that of previously reported extruded fully dense 7075 Al which was not heat treated, and so possessed lower mechanical properties, yield and tensile stresses 254 and 402 MPa, respectively and elongation 10.4 %.
{"title":"Extruded hot compacted alumix 431 powder - mechanical properties and microstructure","authors":"S. Szczepanik, P. Nikiel","doi":"10.2298/sos2301115s","DOIUrl":"https://doi.org/10.2298/sos2301115s","url":null,"abstract":"Extrusion at 450?C of hot compacted premixed aluminium alloy powder 7075 resulted in full density and banded microstructure with the average transverse grain size of 13.6 ?m after T6 heat treatment. It increased mechanical properties to yield and tensile stresses of 457 and 492 MPa, respectively and elongation 6.4 %. These meet the requirements of the ASTM standard ASM for 7075T6 conventionally manufactured alloy of similar chemical composition. The respective microstructures were compared and also to that of previously reported extruded fully dense 7075 Al which was not heat treated, and so possessed lower mechanical properties, yield and tensile stresses 254 and 402 MPa, respectively and elongation 10.4 %.","PeriodicalId":21592,"journal":{"name":"Science of Sintering","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68811824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nickel is covered with very thin oxide film and is stable against corrosion under normal conditions. Nickel, as Ni-NiO-oxidant system, can make much thicker (even a thousand times) and more corrosion unstable oxides. With certain new oxidation process parameters, nickel can undergo so-called accelerated oxidation. The subject and goal of this work is to find the most favorable conditions for performing of accelerated - catastrophic Ni oxidation process, when substitution of V2O5 is carried out into NiO (2V (Ni)), with significant electron concentration increase and oxygen surplus. Unlimited main and secondary charge carriers transfer is significantly facilitated if oxide film with non-stoichiometric composition and defects is formed. The aim is to avoid compact oxide film formation by chemical-thermal treatments and to obtain porous and defective NiO. By using oxidized system Ni - NiO - oxidant in glass, ceramics and evaporated metal technology, extraordinary usable value of this work is ensured.
{"title":"Modification of the Ni-NiO-oxidant system by thermo-chemical oxidation with accelerated growth of the p-type dielectric oxide layer, by the action of substituted V2O5 on the system","authors":"J. Purenovic, M. Purenovic","doi":"10.2298/sos230726049p","DOIUrl":"https://doi.org/10.2298/sos230726049p","url":null,"abstract":"Nickel is covered with very thin oxide film and is stable against corrosion under normal conditions. Nickel, as Ni-NiO-oxidant system, can make much thicker (even a thousand times) and more corrosion unstable oxides. With certain new oxidation process parameters, nickel can undergo so-called accelerated oxidation. The subject and goal of this work is to find the most favorable conditions for performing of accelerated - catastrophic Ni oxidation process, when substitution of V2O5 is carried out into NiO (2V (Ni)), with significant electron concentration increase and oxygen surplus. Unlimited main and secondary charge carriers transfer is significantly facilitated if oxide film with non-stoichiometric composition and defects is formed. The aim is to avoid compact oxide film formation by chemical-thermal treatments and to obtain porous and defective NiO. By using oxidized system Ni - NiO - oxidant in glass, ceramics and evaporated metal technology, extraordinary usable value of this work is ensured.","PeriodicalId":21592,"journal":{"name":"Science of Sintering","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68813215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Pavkov, G. Bakić, Vesna Maksimovic, I. Cvijović-Alagić, D. Bučevac, B. Matović
This paper presents the technological process for obtaining basalt-stainless steel composite materials and testing their physical and mechanical properties. The phases of the technological process consist of: milling, homogenization, pressing, and sintering to obtain composite materials with improved fracture toughness. Andesite basalt from the deposit site "Donje Jarinje", Serbia, was used as a matrix in the composites, while commercial austenitic stainless steel 316L in the amount of 0-30 wt.% was used as a reinforcement. Although the increase of 316L amount caused a continuous decrease in the relative density of sintered samples, the relative density of sample containing 30 wt.% of 316L was above 94%. The 316L grains, which possess a larger coefficient of thermal expansion than the basalt matrix, shrinking faster during cooling from sintering temperature resulting in the formation of compressive residual stress in the basalt matrix surrounding the spherical steel grains. The presence of this stress activated toughening mechanisms such as crack deflection and toughening due to compressive residual stress. The addition of 20 wt.% of reinforcing 316L particles increased the fracture toughness of basalt by more than 30%. The relative density of these samples was measured to be 97%, whereas macrohardness was found to be 6.2 GPa.
{"title":"Novel basalt-stainless steel composite materials with improved fracture toughness","authors":"V. Pavkov, G. Bakić, Vesna Maksimovic, I. Cvijović-Alagić, D. Bučevac, B. Matović","doi":"10.2298/sos220429002p","DOIUrl":"https://doi.org/10.2298/sos220429002p","url":null,"abstract":"This paper presents the technological process for obtaining basalt-stainless steel composite materials and testing their physical and mechanical properties. The phases of the technological process consist of: milling, homogenization, pressing, and sintering to obtain composite materials with improved fracture toughness. Andesite basalt from the deposit site \"Donje Jarinje\", Serbia, was used as a matrix in the composites, while commercial austenitic stainless steel 316L in the amount of 0-30 wt.% was used as a reinforcement. Although the increase of 316L amount caused a continuous decrease in the relative density of sintered samples, the relative density of sample containing 30 wt.% of 316L was above 94%. The 316L grains, which possess a larger coefficient of thermal expansion than the basalt matrix, shrinking faster during cooling from sintering temperature resulting in the formation of compressive residual stress in the basalt matrix surrounding the spherical steel grains. The presence of this stress activated toughening mechanisms such as crack deflection and toughening due to compressive residual stress. The addition of 20 wt.% of reinforcing 316L particles increased the fracture toughness of basalt by more than 30%. The relative density of these samples was measured to be 97%, whereas macrohardness was found to be 6.2 GPa.","PeriodicalId":21592,"journal":{"name":"Science of Sintering","volume":"25 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68809545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Nenadovic, M. Ivanović, Danilo Kisić, N. Bundaleski, V. Pavlović, Sanja Knežević, Ljiljana M. Kljajević
In the present paper, polymerization of alkali activated metakaolin (MK) and its structural changing, using 2M NaOH, 8M NaOH, and 16M NaOH solutions were followed by means of X-ray photoelectron spectroscopy (XPS), Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), Raman spectroscopy and Scanning electron microscopy (SEM). XPS analysis revealed that changing of NaOH concentration did not affect the types of formed bonds in the material. At the same time, the amount of sodium and aluminum increased with the NaOH molarity. The latter steps could be especially interesting because it may indicate the possibility of 'dosing' the amount of Al incorporated by changing the NaOH concentration in the solution. DRIFT analysis revealed that the absorption band for AlIV located at 800 cm-1 is shifted towards the smaller values. Changing the concentration of NaOH, the chemical content did not change, but the structural changes are observed. Raman spectroscopy detected that the most dominant peaks at ?400 cm-1 and 519 cm-1 originate from Si-O-Al and Si-O-Si bending modes. With increasing the NaOH concentration, peaks at 1019-1060 cm-1 become more prominent as a result of polymerization. Both analyzes (DRIFT and Raman) confirmed the presence of quartz. SEM analysis showed that different structures are created by changing the concentration of NaOH.
{"title":"Changes in the physicochemical properties of geopolymer gels as a function of NaOH concentration","authors":"M. Nenadovic, M. Ivanović, Danilo Kisić, N. Bundaleski, V. Pavlović, Sanja Knežević, Ljiljana M. Kljajević","doi":"10.2298/sos220624020n","DOIUrl":"https://doi.org/10.2298/sos220624020n","url":null,"abstract":"In the present paper, polymerization of alkali activated metakaolin (MK) and its structural changing, using 2M NaOH, 8M NaOH, and 16M NaOH solutions were followed by means of X-ray photoelectron spectroscopy (XPS), Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), Raman spectroscopy and Scanning electron microscopy (SEM). XPS analysis revealed that changing of NaOH concentration did not affect the types of formed bonds in the material. At the same time, the amount of sodium and aluminum increased with the NaOH molarity. The latter steps could be especially interesting because it may indicate the possibility of 'dosing' the amount of Al incorporated by changing the NaOH concentration in the solution. DRIFT analysis revealed that the absorption band for AlIV located at 800 cm-1 is shifted towards the smaller values. Changing the concentration of NaOH, the chemical content did not change, but the structural changes are observed. Raman spectroscopy detected that the most dominant peaks at ?400 cm-1 and 519 cm-1 originate from Si-O-Al and Si-O-Si bending modes. With increasing the NaOH concentration, peaks at 1019-1060 cm-1 become more prominent as a result of polymerization. Both analyzes (DRIFT and Raman) confirmed the presence of quartz. SEM analysis showed that different structures are created by changing the concentration of NaOH.","PeriodicalId":21592,"journal":{"name":"Science of Sintering","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68810428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A cross section set for scattering Ne+ ions in CF4 gas is assessed by using available experimental data for charge transfer cross sections. Calculated cross sections can be used to obtain transport parameters, specially characteristic energy and reduced mobilty for low and moderate reduced electric fields E/N (E-electric field strength; N-gas density) and accounting for the non-conservative collisions. These data are needed for modelling in numerous applications of technologically importance.
{"title":"Characteristic energy and reduced mobility for Ne+ ions in CF4 gas","authors":"Z. Nikitovic, Z. Raspopovic","doi":"10.2298/sos220620021n","DOIUrl":"https://doi.org/10.2298/sos220620021n","url":null,"abstract":"A cross section set for scattering Ne+ ions in CF4 gas is assessed by using available experimental data for charge transfer cross sections. Calculated cross sections can be used to obtain transport parameters, specially characteristic energy and reduced mobilty for low and moderate reduced electric fields E/N (E-electric field strength; N-gas density) and accounting for the non-conservative collisions. These data are needed for modelling in numerous applications of technologically importance.","PeriodicalId":21592,"journal":{"name":"Science of Sintering","volume":"8 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68810878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Powder Injection Molding (PIM) method is widely used in the production of parts with complex geometries and small volumes. To solve the volume limitation in PIM, the Inserted Powder Injection Molding (IPIM) method was developed. In this study, the effect of insert surface roughness on shear strength was investigated using the IPIM method in the production of WC-9%Co parts. Firstly, inserts with five different surface roughness (Ra, ?m), 1.5 - 2.1 - 3.3 - 4 - 4.6, were prepared from 4340 steel for the research. WC feedstock was injected onto the prepared inserts. Following the injection process, the samples were subjected to debinding and sintering processes. Compression tests were performed on sintered specimens, and the effect of surface roughness on diffusion bonding strength was investigated. As a result of the experiments, it was determined that the shear strength increases with the increase of the insert surface roughness. The maximum shear strength (118.4 MPa) was obtained in samples with an insert surface roughness of 4.6 ?m.
{"title":"The effect of insert surface roughness in part production with inserted powder injection molding method","authors":"Kamran Samet, M. Subaşı, C. Karatas","doi":"10.2298/sos2301089s","DOIUrl":"https://doi.org/10.2298/sos2301089s","url":null,"abstract":"The Powder Injection Molding (PIM) method is widely used in the production of parts with complex geometries and small volumes. To solve the volume limitation in PIM, the Inserted Powder Injection Molding (IPIM) method was developed. In this study, the effect of insert surface roughness on shear strength was investigated using the IPIM method in the production of WC-9%Co parts. Firstly, inserts with five different surface roughness (Ra, ?m), 1.5 - 2.1 - 3.3 - 4 - 4.6, were prepared from 4340 steel for the research. WC feedstock was injected onto the prepared inserts. Following the injection process, the samples were subjected to debinding and sintering processes. Compression tests were performed on sintered specimens, and the effect of surface roughness on diffusion bonding strength was investigated. As a result of the experiments, it was determined that the shear strength increases with the increase of the insert surface roughness. The maximum shear strength (118.4 MPa) was obtained in samples with an insert surface roughness of 4.6 ?m.","PeriodicalId":21592,"journal":{"name":"Science of Sintering","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68811776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Adela Egelja, Andrija Savic, Marjetka Savic, Maja Kokunesoski, Krstimir Pantic, Milica Rancic, Marija Vuksanovic
In present study FeAl-LDH@SiO2 adsorbent was used for phosphate and arsenate removal from aqueous solutions. Silica, obtained from rice husks, was used as a substrate for the deposition of FeAl based layered double hydroxides (FeAl-LDH) particles. Synthesis of FeAl-LDH, obtained at Fe/Al molar ratio of 3:1, was performed via co-precipitation and concomitant deposition on SiO2 carrier at 1:1, 2:1, and 3:1 LDH/silica mass ratios. The prepared materials were characterized by scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), N2 adsorption/desorption isotherms (BET method) and Fourier transform infrared spectroscopy (FTIR). SEM analysis revealed uniform precipitate of LDH on SiO2 substrate, while XRD analysis confirmed crystallographic structure of LDH deposit. Optimization of adsorption properties of synthesized adsorbents confirmed best performances of FeAl-LDH@SiO2, obtained at 3:1 LDH/silica mass ratio. Thus, adsorption experiments were carried out with respect to adsorbent dosage, phosphate and arsenate concentration at initial pH 4. Phosphate concentrations were determined using spectrophotometer and arsenate concentrations were determined using atomic absorption spectrometer. The results showed that the maximum sorption capacities for phosphates was 62.2 mg g-1, and for arsenate was 59.0 mg g-1. Kinetic study confirmed intra-particle diffusion as rate-limiting step, while thermodynamic study indicates feasible and spontaneous process.
{"title":"Application of Fe-Al layered double hydroxides on silica for phosphate and arsenate removal from water","authors":"Adela Egelja, Andrija Savic, Marjetka Savic, Maja Kokunesoski, Krstimir Pantic, Milica Rancic, Marija Vuksanovic","doi":"10.2298/sos230926051e","DOIUrl":"https://doi.org/10.2298/sos230926051e","url":null,"abstract":"In present study FeAl-LDH@SiO2 adsorbent was used for phosphate and arsenate removal from aqueous solutions. Silica, obtained from rice husks, was used as a substrate for the deposition of FeAl based layered double hydroxides (FeAl-LDH) particles. Synthesis of FeAl-LDH, obtained at Fe/Al molar ratio of 3:1, was performed via co-precipitation and concomitant deposition on SiO2 carrier at 1:1, 2:1, and 3:1 LDH/silica mass ratios. The prepared materials were characterized by scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), N2 adsorption/desorption isotherms (BET method) and Fourier transform infrared spectroscopy (FTIR). SEM analysis revealed uniform precipitate of LDH on SiO2 substrate, while XRD analysis confirmed crystallographic structure of LDH deposit. Optimization of adsorption properties of synthesized adsorbents confirmed best performances of FeAl-LDH@SiO2, obtained at 3:1 LDH/silica mass ratio. Thus, adsorption experiments were carried out with respect to adsorbent dosage, phosphate and arsenate concentration at initial pH 4. Phosphate concentrations were determined using spectrophotometer and arsenate concentrations were determined using atomic absorption spectrometer. The results showed that the maximum sorption capacities for phosphates was 62.2 mg g-1, and for arsenate was 59.0 mg g-1. Kinetic study confirmed intra-particle diffusion as rate-limiting step, while thermodynamic study indicates feasible and spontaneous process.","PeriodicalId":21592,"journal":{"name":"Science of Sintering","volume":"115 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135841218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Simić, J. Ružić, D. Božić, N. Stoymenov, S. Goshev, D. Karastoyanov, J. Stašić
Copper-zirconium alloys with high conductivity were produced using powder metallurgy. Two-steps manufacturing process, containing mechanical alloying followed by hot pressing, was applied in achieving improved mechanical and physical properties of Cu-Zr alloy. In this paper, the influence of boron on Cu-Zr alloys properties was studied on Cu-1Zr (wt.%) and Cu-1.1Zr-0.3B (wt.%) systems. Scanning electron microscopy, laser nanoparticle sizer, computed tomography and X-ray diffraction were employed for observation of changes in the microstructure during production steps. More specifically - variations in size of the Cu particles, powder mixtures? structural parameters, and development of CuZr phase in binary alloy, CuZr phase and ZrB2 particles in ternary alloy were observed. It was shown that presence of boron increases dislocation density in ternary alloy over the mechanical alloying time compared to binary alloy. The results presented in this study show higher hardening effect in Cu-Zr- B alloy compared to Cu-Zr alloy, resulting in stable hardness values during thermomechanical treatment. Further, it can be seen that finely dispersed reinforcing ZrB2 particles in copper matrix does not have significant influence on its conductivity. Moreover, both systems Cu-Zr and Cu-Zr-B exhibit better electrical conductivity after thermomechanical treatment as a result of zirconium reduction in solid solution due to its precipitation.
{"title":"The influence of boron addition on properties of copper-zirconium alloys","authors":"M. Simić, J. Ružić, D. Božić, N. Stoymenov, S. Goshev, D. Karastoyanov, J. Stašić","doi":"10.2298/sos220421003s","DOIUrl":"https://doi.org/10.2298/sos220421003s","url":null,"abstract":"Copper-zirconium alloys with high conductivity were produced using powder metallurgy. Two-steps manufacturing process, containing mechanical alloying followed by hot pressing, was applied in achieving improved mechanical and physical properties of Cu-Zr alloy. In this paper, the influence of boron on Cu-Zr alloys properties was studied on Cu-1Zr (wt.%) and Cu-1.1Zr-0.3B (wt.%) systems. Scanning electron microscopy, laser nanoparticle sizer, computed tomography and X-ray diffraction were employed for observation of changes in the microstructure during production steps. More specifically - variations in size of the Cu particles, powder mixtures? structural parameters, and development of CuZr phase in binary alloy, CuZr phase and ZrB2 particles in ternary alloy were observed. It was shown that presence of boron increases dislocation density in ternary alloy over the mechanical alloying time compared to binary alloy. The results presented in this study show higher hardening effect in Cu-Zr- B alloy compared to Cu-Zr alloy, resulting in stable hardness values during thermomechanical treatment. Further, it can be seen that finely dispersed reinforcing ZrB2 particles in copper matrix does not have significant influence on its conductivity. Moreover, both systems Cu-Zr and Cu-Zr-B exhibit better electrical conductivity after thermomechanical treatment as a result of zirconium reduction in solid solution due to its precipitation.","PeriodicalId":21592,"journal":{"name":"Science of Sintering","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68809500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Terzic, M. Vasić, J. Stojanovic, V. Pavlovic, Z. Radojević
Phyllosilicate mineral pyrophyllite is predominantly used in the ceramic industry because it exhibits high refractoriness. Due to its thermal transformation into mullite, pyrophyllite is stable at elevated temperatures, making it a suitable mineral additive for refractory non-shaped materials and various ceramic shaped products. In this study, pyrophyllite is employed as 50 % clay replacement in the ceramics and up to 30 % cement replacement in mortars. Physico-mechanical properties were investigated. The firing shrinkage in the ceramics treated at 1200?C was reduced by pyrophyllite addition. Pyrophyllite acted as additional pozzolana during cement hydration. Within the microstructure, it formed micro-reinforcement in the shape of crystalline folia, which improves the mechanical properties of ordinary Portland cement, high aluminate cement, and blended cement mortars. The investigation proved the efficiency and suitability of pyrophyllite employed as a substitution for clay in ceramics and a cement replacement in mortars.
{"title":"Application of pyrophyllite in high-temperature treated building materials","authors":"A. Terzic, M. Vasić, J. Stojanovic, V. Pavlovic, Z. Radojević","doi":"10.2298/sos220610014t","DOIUrl":"https://doi.org/10.2298/sos220610014t","url":null,"abstract":"Phyllosilicate mineral pyrophyllite is predominantly used in the ceramic industry because it exhibits high refractoriness. Due to its thermal transformation into mullite, pyrophyllite is stable at elevated temperatures, making it a suitable mineral additive for refractory non-shaped materials and various ceramic shaped products. In this study, pyrophyllite is employed as 50 % clay replacement in the ceramics and up to 30 % cement replacement in mortars. Physico-mechanical properties were investigated. The firing shrinkage in the ceramics treated at 1200?C was reduced by pyrophyllite addition. Pyrophyllite acted as additional pozzolana during cement hydration. Within the microstructure, it formed micro-reinforcement in the shape of crystalline folia, which improves the mechanical properties of ordinary Portland cement, high aluminate cement, and blended cement mortars. The investigation proved the efficiency and suitability of pyrophyllite employed as a substitution for clay in ceramics and a cement replacement in mortars.","PeriodicalId":21592,"journal":{"name":"Science of Sintering","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68810234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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