Pub Date : 2023-01-01DOI: 10.3934/matersci.2023012
Tomáš Meluš, R. Koleňák, J. Drápala, P. Babincová, Matej Pašák
The aim of this research was to study the interaction and solderability of Al2O3 ceramics and Ni-SiC composite by use of an active solder type Bi11Ag1.5Ti1Mg. The chemical composition of the solder is 86.5 wt% Bi, 11 wt% Ag, 1.5 wt% Ti, 1 wt% Mg. Soldering was performed by ultrasonic activation. This solder has a wide melting interval with the initial melting temperature of 263 ℃, what corresponds to the eutectic reaction. The liquidus temperature of this solder was determined at 437 ℃. The bond between the ceramic and the solder is formed by the interaction of the active metals Bi, Ag and Mg with the surface of the substrate Al2O3. The thickness of the Mg reaction layer at the interface was approximately 0.8 μm. The bond at the interface between Ni-SiC and solder was formed due to the interaction of the active metals Bi, Ag, Mg and Ti. Feasibility of Bi11Ag1.5Ti1Mg solder was assessed on the basis of analyses of joint boundaries and joint shear strength measurements. The average shear strength of Al2O3/Bi11Ag1.5Ti1Mg/Ni-SiC joint was 54 MPa.
{"title":"Ultrasonic soldering of Al2O3 ceramics and Ni-SiC composite by use of Bi-based active solder","authors":"Tomáš Meluš, R. Koleňák, J. Drápala, P. Babincová, Matej Pašák","doi":"10.3934/matersci.2023012","DOIUrl":"https://doi.org/10.3934/matersci.2023012","url":null,"abstract":"The aim of this research was to study the interaction and solderability of Al2O3 ceramics and Ni-SiC composite by use of an active solder type Bi11Ag1.5Ti1Mg. The chemical composition of the solder is 86.5 wt% Bi, 11 wt% Ag, 1.5 wt% Ti, 1 wt% Mg. Soldering was performed by ultrasonic activation. This solder has a wide melting interval with the initial melting temperature of 263 ℃, what corresponds to the eutectic reaction. The liquidus temperature of this solder was determined at 437 ℃. The bond between the ceramic and the solder is formed by the interaction of the active metals Bi, Ag and Mg with the surface of the substrate Al2O3. The thickness of the Mg reaction layer at the interface was approximately 0.8 μm. The bond at the interface between Ni-SiC and solder was formed due to the interaction of the active metals Bi, Ag, Mg and Ti. Feasibility of Bi11Ag1.5Ti1Mg solder was assessed on the basis of analyses of joint boundaries and joint shear strength measurements. The average shear strength of Al2O3/Bi11Ag1.5Ti1Mg/Ni-SiC joint was 54 MPa.","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70089760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3934/matersci.2023041
Mohamed Lokman Jalaluddin, U. Azlan, Mohd Warikh Abd Rashid
This paper is a study of porous ceramics from a mixture of clay (kaolinite), silica (silicon dioxide), and feldspar by adding the carbon black (CB) with different contents. The results were presented in terms of apparent porosity, relative density, microstructure and porous characteristic, flexural strength and phase formation. As observed, the sintering at 1200 ℃ is the optimum temperature in this work. In comparison to the samples without CB content, the apparent porosity and relative density of ceramics are highly dependent on the CB contents. This might be attributed to the presence of porous structure as seen in SEM images on the fracture surface of ceramics. It also revealed that the addition of CB resulted in smaller pore sizes and a more uniform pore distribution. The creation of pores in porous ceramics was mainly attributed to the loss of shape of CB microspheres at high temperatures, as observed from SEM. The flexural strength of the sintered samples exhibited an average decrease from 60 to 55 MPa due to the presence of CB, which is typically known to reduce the mechanical properties with high porosity. In XRD results, the muscovite phase is represented by a few of peaks with significant intensities, while the rest peaks are of undetermined phase. The strongest peak at a 26° of 2θ angle, suggesting the presence of potassium and aluminium in the form of silicate minerals.
{"title":"A preliminary study of porous ceramics with carbon black contents","authors":"Mohamed Lokman Jalaluddin, U. Azlan, Mohd Warikh Abd Rashid","doi":"10.3934/matersci.2023041","DOIUrl":"https://doi.org/10.3934/matersci.2023041","url":null,"abstract":"This paper is a study of porous ceramics from a mixture of clay (kaolinite), silica (silicon dioxide), and feldspar by adding the carbon black (CB) with different contents. The results were presented in terms of apparent porosity, relative density, microstructure and porous characteristic, flexural strength and phase formation. As observed, the sintering at 1200 ℃ is the optimum temperature in this work. In comparison to the samples without CB content, the apparent porosity and relative density of ceramics are highly dependent on the CB contents. This might be attributed to the presence of porous structure as seen in SEM images on the fracture surface of ceramics. It also revealed that the addition of CB resulted in smaller pore sizes and a more uniform pore distribution. The creation of pores in porous ceramics was mainly attributed to the loss of shape of CB microspheres at high temperatures, as observed from SEM. The flexural strength of the sintered samples exhibited an average decrease from 60 to 55 MPa due to the presence of CB, which is typically known to reduce the mechanical properties with high porosity. In XRD results, the muscovite phase is represented by a few of peaks with significant intensities, while the rest peaks are of undetermined phase. The strongest peak at a 26° of 2θ angle, suggesting the presence of potassium and aluminium in the form of silicate minerals.","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70090893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3934/matersci.2023004
Vinda Puspasari, Satrio Herbirowo, A. M. Habieb, Dedi Pria Utama, R. Roberto, B. Adjiantoro
Low alloy nickel steel was chosen for this experiment because it is suitable for grinding balls application due to its high hardness and corrosion resistance. This study aimed to see the effect of different sub-zero treatments on the hardness, fractography and corrosion properties of low alloy nickel steel. The prepared specimens were heated to the austenitizing temperature of 980 ℃ in a furnace for one hour and water-quenched until they reached room temperature. Furthermore, the quenched specimens were chilled in liquid nitrogen for a variated time of 10, 60 or 360 min, followed by tempering treatment at 200 ℃ for one hour. According to the hardness test, the sub-zero treatment is effective in hardening materials, where the hardness value increases as the sub-zero treatment time increases, ranging from 204.93 to 417.98 HV. The fractography test indicated ductile fracture characterized by dimples at the fractured surface. Moreover, the corrosion test showed an enhancement of corrosion resistance with increased sub-zero treatment time.
{"title":"Effect of sub-zero treatments on hardness and corrosion properties of low-alloy nickel steel","authors":"Vinda Puspasari, Satrio Herbirowo, A. M. Habieb, Dedi Pria Utama, R. Roberto, B. Adjiantoro","doi":"10.3934/matersci.2023004","DOIUrl":"https://doi.org/10.3934/matersci.2023004","url":null,"abstract":"Low alloy nickel steel was chosen for this experiment because it is suitable for grinding balls application due to its high hardness and corrosion resistance. This study aimed to see the effect of different sub-zero treatments on the hardness, fractography and corrosion properties of low alloy nickel steel. The prepared specimens were heated to the austenitizing temperature of 980 ℃ in a furnace for one hour and water-quenched until they reached room temperature. Furthermore, the quenched specimens were chilled in liquid nitrogen for a variated time of 10, 60 or 360 min, followed by tempering treatment at 200 ℃ for one hour. According to the hardness test, the sub-zero treatment is effective in hardening materials, where the hardness value increases as the sub-zero treatment time increases, ranging from 204.93 to 417.98 HV. The fractography test indicated ductile fracture characterized by dimples at the fractured surface. Moreover, the corrosion test showed an enhancement of corrosion resistance with increased sub-zero treatment time.","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70089077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3934/matersci.2023007
O. Ouabouch, Imad Ait Laasri, ounir Kriraa, M. Lamsaadi
In this study, we numerically investigated the hydrothermal performance of a parabolic trough solar collector system in which nanofluids are used to transfer thermal energy. The single-phase model has been used to evaluate the respective influences of the spherical shape of nanoparticles with a volume fraction of (φ = 3%), Reynolds number varying between 50,000 ≤ Re ≤ 250,000 and the insertion of a turbulator with and without a twisted configuration on the hydrothermal characteristics created by the turbulent forced convection of a CuO/water nanofluid. The shaped turbulator (+) inserted in the absorber tube had a length turb_L = 2.4 m, a height turb_H = 40 mm and a width turb_t = 2 mm. In the second configuration, the considered turbulator was twisted (N_twist = 5, 10 and 15 twists). The turbulator was positioned at 0.6 m from the inlet of the tube and 1 m from the outlet of the collector. The studied performances included the heat transfer characteristics, pressure drop, friction factor, thermal efficiency, temperature and velocity distribution of the outlet field. The most significant contribution of this study is the proposal of the best parameters to increase the thermal and hydraulic efficiency of parabolic troughs by adding a new turbulator with the considered twists.
{"title":"Investigation of novel turbulator with and without twisted configuration under turbulent forced convection of a CuO/water nanofluid flow inside a parabolic trough solar collector","authors":"O. Ouabouch, Imad Ait Laasri, ounir Kriraa, M. Lamsaadi","doi":"10.3934/matersci.2023007","DOIUrl":"https://doi.org/10.3934/matersci.2023007","url":null,"abstract":"In this study, we numerically investigated the hydrothermal performance of a parabolic trough solar collector system in which nanofluids are used to transfer thermal energy. The single-phase model has been used to evaluate the respective influences of the spherical shape of nanoparticles with a volume fraction of (φ = 3%), Reynolds number varying between 50,000 ≤ Re ≤ 250,000 and the insertion of a turbulator with and without a twisted configuration on the hydrothermal characteristics created by the turbulent forced convection of a CuO/water nanofluid. The shaped turbulator (+) inserted in the absorber tube had a length turb_L = 2.4 m, a height turb_H = 40 mm and a width turb_t = 2 mm. In the second configuration, the considered turbulator was twisted (N_twist = 5, 10 and 15 twists). The turbulator was positioned at 0.6 m from the inlet of the tube and 1 m from the outlet of the collector. The studied performances included the heat transfer characteristics, pressure drop, friction factor, thermal efficiency, temperature and velocity distribution of the outlet field. The most significant contribution of this study is the proposal of the best parameters to increase the thermal and hydraulic efficiency of parabolic troughs by adding a new turbulator with the considered twists.","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70089839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3934/matersci.2023028
Y. M. Pusparizkita, Vivi A. Fardilah, Christian Aslan, J. Jamari, A. Bayuseno
The current laboratory experiments investigated the corrosion resistance of carbon steel in artificial seawater (ASW) using the steel coupons hanging on a closed glass reactor of ASW with volume-to-specimen area ratios ranging from 0.20 to 0.40 mL/mm2. These coupons were immersed in ASW for varying time durations (7 and 14 d) at room temperature without agitation. Further, the corrosion rates based on the weight loss and electrochemical analytical method were determined. Following exposure to carbon steel for 7 and 14 d, corrosion rates were 0.2780 mmpy and 0.3092 mmpy, respectively. The surfaces appeared to be not protected by oxides based on this result. The electrochemical impedance spectrometer in potentiostatic/galvanostatic mode, in conjunction with EDX analysis, predicted the evolution of oxygen reduction. The 7th-day immersion sample had a higher oxygen content, and the 14th-day immersion sample had a slightly lower oxygen content. Methods of X-ray diffraction (XRD) and scanning electron microscopy (SEM) characterized the surface morphology and composition of their corrosion product. Corrosion products derived from rust minerals hematite, lepidocrocite and magnetite appeared to cover the carbon steel surface after exposure. This result can get insight into the corrosion behavior of low-carbon steel used in marine environments.
{"title":"Understanding of low-carbon steel marine corrosion through simulation in artificial seawater","authors":"Y. M. Pusparizkita, Vivi A. Fardilah, Christian Aslan, J. Jamari, A. Bayuseno","doi":"10.3934/matersci.2023028","DOIUrl":"https://doi.org/10.3934/matersci.2023028","url":null,"abstract":"The current laboratory experiments investigated the corrosion resistance of carbon steel in artificial seawater (ASW) using the steel coupons hanging on a closed glass reactor of ASW with volume-to-specimen area ratios ranging from 0.20 to 0.40 mL/mm2. These coupons were immersed in ASW for varying time durations (7 and 14 d) at room temperature without agitation. Further, the corrosion rates based on the weight loss and electrochemical analytical method were determined. Following exposure to carbon steel for 7 and 14 d, corrosion rates were 0.2780 mmpy and 0.3092 mmpy, respectively. The surfaces appeared to be not protected by oxides based on this result. The electrochemical impedance spectrometer in potentiostatic/galvanostatic mode, in conjunction with EDX analysis, predicted the evolution of oxygen reduction. The 7th-day immersion sample had a higher oxygen content, and the 14th-day immersion sample had a slightly lower oxygen content. Methods of X-ray diffraction (XRD) and scanning electron microscopy (SEM) characterized the surface morphology and composition of their corrosion product. Corrosion products derived from rust minerals hematite, lepidocrocite and magnetite appeared to cover the carbon steel surface after exposure. This result can get insight into the corrosion behavior of low-carbon steel used in marine environments.","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70090218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3934/matersci.2023029
Aleksander Panichkin, A. Uskenbayeva, A. Kenzhegulov, A. Mamaeva, A. Imbarova, B. Kshibekova, Zhassulan Alibekov, D. Nurhadiyanto, Isti Yunita
Article considers the influence of additions of rare earth elements such as Sm, La, Ce, Nd, and Y on the structure and properties of hypereutectic high-chromium white cast iron of grade G-X300CrMo27-2. To obtain an increased content of carbides in the studied cast iron samples, the carbon content was 3.75–3.9 and 4.1–4.2 wt%. The amount of rare earth elements additives added to the melt is 0.2% by weight. Data were obtained on the effect of overheating and cooling rate in the crystallization interval on the effect of rare earth additives, the structure and properties of white cast iron castings are given. According to the results of the microprobe analysis, it was shown that, under the chosen crystallization conditions, Sm, La, and Ce can form solid solutions with primary and eutectic carbides (FeCr)7C3. La and Ce form solid solutions with austenite. Nd and Y do not dissolve in iron chromium phases. All listed rare earth elements form phosphides and oxyphosphides. Experimental data are presented on the effect of rare earth elements on the size of primary (FeCr)7C3 carbides and a hypothesis is proposed on the effect of rare earth elements on the crystallization process of hypereutectic chromium white cast irons. Experimental data are presented on the effect of REE additives on the microhardness of phases, hardness, strength, and resistance to abrasive wear of cast iron castings. It was found that the introduction of these additives into hypereutectic chromium white cast iron does not contribute to the modification of the structure and leads to an increase in the size of primary crystals, as well as a decrease in their mechanical properties. However, the addition of Y increases the abrasive wear resistance, but reduces the strength of castings made from such white cast iron.
{"title":"Assessment of the effect of small additions of some rare earth elements on the structure and mechanical properties of castings from hypereutectic chromium white irons","authors":"Aleksander Panichkin, A. Uskenbayeva, A. Kenzhegulov, A. Mamaeva, A. Imbarova, B. Kshibekova, Zhassulan Alibekov, D. Nurhadiyanto, Isti Yunita","doi":"10.3934/matersci.2023029","DOIUrl":"https://doi.org/10.3934/matersci.2023029","url":null,"abstract":"Article considers the influence of additions of rare earth elements such as Sm, La, Ce, Nd, and Y on the structure and properties of hypereutectic high-chromium white cast iron of grade G-X300CrMo27-2. To obtain an increased content of carbides in the studied cast iron samples, the carbon content was 3.75–3.9 and 4.1–4.2 wt%. The amount of rare earth elements additives added to the melt is 0.2% by weight. Data were obtained on the effect of overheating and cooling rate in the crystallization interval on the effect of rare earth additives, the structure and properties of white cast iron castings are given. According to the results of the microprobe analysis, it was shown that, under the chosen crystallization conditions, Sm, La, and Ce can form solid solutions with primary and eutectic carbides (FeCr)7C3. La and Ce form solid solutions with austenite. Nd and Y do not dissolve in iron chromium phases. All listed rare earth elements form phosphides and oxyphosphides. Experimental data are presented on the effect of rare earth elements on the size of primary (FeCr)7C3 carbides and a hypothesis is proposed on the effect of rare earth elements on the crystallization process of hypereutectic chromium white cast irons. Experimental data are presented on the effect of REE additives on the microhardness of phases, hardness, strength, and resistance to abrasive wear of cast iron castings. It was found that the introduction of these additives into hypereutectic chromium white cast iron does not contribute to the modification of the structure and leads to an increase in the size of primary crystals, as well as a decrease in their mechanical properties. However, the addition of Y increases the abrasive wear resistance, but reduces the strength of castings made from such white cast iron.","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70090320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3934/matersci.2023053
Nikolaos D. Papadopoulos, Polyxeni Vourna, Pinelopi P. Falara, Panagiota Koutsaftiki, Sotirios Xafakis
Fouling of surfaces caused by pollution, contamination, humidity and microorganisms is one of the major sources of the degradation of mineral and composite materials. The inhibition of foulant growth is essential for the prevention of different kinds of damage, ranging from aesthetic, mechanical and chemical, to risks concerning human and environmental health. This study proposes a new approach for the development of a transparent preservative material with water-repellent and biocide attributes through the use of a sol-gel method. It was found that Si–O–Si dense networks can effectively grow into the micro-pores of mineral and cellulose-based materials, promoting self-cleaning properties as well as sufficient protection against bio-fouling.
{"title":"Dual-function coatings to protect absorbent surfaces from fouling","authors":"Nikolaos D. Papadopoulos, Polyxeni Vourna, Pinelopi P. Falara, Panagiota Koutsaftiki, Sotirios Xafakis","doi":"10.3934/matersci.2023053","DOIUrl":"https://doi.org/10.3934/matersci.2023053","url":null,"abstract":"<abstract> <p>Fouling of surfaces caused by pollution, contamination, humidity and microorganisms is one of the major sources of the degradation of mineral and composite materials. The inhibition of foulant growth is essential for the prevention of different kinds of damage, ranging from aesthetic, mechanical and chemical, to risks concerning human and environmental health. This study proposes a new approach for the development of a transparent preservative material with water-repellent and biocide attributes through the use of a sol-gel method. It was found that Si–O–Si dense networks can effectively grow into the micro-pores of mineral and cellulose-based materials, promoting self-cleaning properties as well as sufficient protection against bio-fouling.</p> </abstract>","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135660996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article presents the results of a study on the effect of electrolyte-plasma cementation on the phase composition of the surface-modified layer and the mechanical properties of 20X steel using different solutions. It has been determined that electrolyte-plasma cementation followed by quenching in solutions containing (a) 10% calcined soda (Na2CO3), 10% urea (CH4N2O), 10% glycerin (C3H8O3) and 70% distilled water and (b) 10% calcined soda (Na2CO3), 20% urea (CH4N2O) and 70% distilled water, results in the formation of a modified structure on the surface of 20X steel. This structure mainly consists of the α-Fe phase, along with separate particles of reinforcing phases, Fe3C and Fe3C7 carbides and martensitic αx-Fe phase. The plasma of the electrolyte was used to heat the samples. Then these samples were partially immersed in the electrolyte and held at a temperature of 950 ℃ for 5 min, followed by quenching. As a result of this process, it was found that 20X steel exhibits higher hardness. After the electrolyte plasma cementation, it was observed that the friction coefficient of the modified surface of the steel samples significantly decreased. Additionally, the wear volume was reduced by more than 6.5 times compared to the initial state. The average microhardness after the electrolyte-plasma cementation is 660 HV, which is nearly four times higher than that of the initial material.
{"title":"Investigation on the effect of technological parameters of electrolyte-plasma cementation method on phase structure and mechanical properties of structural steel 20X","authors":"Bauyrzhan Rakhadilov, Lyaila Bayatanova, Sherzod Kurbanbekov, Ravil Sulyubayev, Nurdaulet Shektibayev, Nurbol Berdimuratov","doi":"10.3934/matersci.2023050","DOIUrl":"https://doi.org/10.3934/matersci.2023050","url":null,"abstract":"<abstract> <p>This article presents the results of a study on the effect of electrolyte-plasma cementation on the phase composition of the surface-modified layer and the mechanical properties of 20X steel using different solutions. It has been determined that electrolyte-plasma cementation followed by quenching in solutions containing (a) 10% calcined soda (Na<sub>2</sub>CO<sub>3</sub>), 10% urea (CH<sub>4</sub>N<sub>2</sub>O), 10% glycerin (C<sub>3</sub>H<sub>8</sub>O<sub>3</sub>) and 70% distilled water and (b) 10% calcined soda (Na<sub>2</sub>CO<sub>3</sub>), 20% urea (CH<sub>4</sub>N<sub>2</sub>O) and 70% distilled water, results in the formation of a modified structure on the surface of 20X steel. This structure mainly consists of the α-Fe phase, along with separate particles of reinforcing phases, Fe<sub>3</sub>C and Fe<sub>3</sub>C<sub>7</sub> carbides and martensitic αx-Fe phase. The plasma of the electrolyte was used to heat the samples. Then these samples were partially immersed in the electrolyte and held at a temperature of 950 ℃ for 5 min, followed by quenching. As a result of this process, it was found that 20X steel exhibits higher hardness. After the electrolyte plasma cementation, it was observed that the friction coefficient of the modified surface of the steel samples significantly decreased. Additionally, the wear volume was reduced by more than 6.5 times compared to the initial state. The average microhardness after the electrolyte-plasma cementation is 660 HV, which is nearly four times higher than that of the initial material.</p> </abstract>","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135156715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3934/matersci.2023014
Nilesh Shahapure, Dattaji K. Shinde, A. Kelkar
Epoxy resins are formed when epoxy monomers react with crosslinkers that have active hydrogen sites on them such as amine and anhydrides. These cross-linked structures are highly unpredictable and depend on different parameters during curing. Epoxy material when reinforced with nanoparticles has got importance because of its extraordinary enhanced mechanical and thermal properties for structural application. Experimentally it is challenging to tailor these nanostructures and manufacture epoxy-based nanocomposites with desired properties. An experimental approach to preparing these is tedious and costly. The improvement of such materials requires huge experimentation and a better level of control of their properties can't be accomplished up till now. There is a need for numerical experimentation to guide these experimental procedures. With the headway of computational techniques, an alternative for these experiments had given an effective method to characterize these nanocomposites and study their reaction kinetics. Molecular dynamics (MD) simulation is one such technique that works on density function theory and Newton*s second law to characterize these materials with different permutations and combinations during their curing. This review is carried out for MD simulation studies done to date on different epoxies and epoxy-based nanocomposites for their thermal, mechanical, and thermo-mechanical characterization.
{"title":"Atomistic modeling and molecular dynamic simulation of polymer nanocomposites for thermal and mechanical property characterization: A review","authors":"Nilesh Shahapure, Dattaji K. Shinde, A. Kelkar","doi":"10.3934/matersci.2023014","DOIUrl":"https://doi.org/10.3934/matersci.2023014","url":null,"abstract":"Epoxy resins are formed when epoxy monomers react with crosslinkers that have active hydrogen sites on them such as amine and anhydrides. These cross-linked structures are highly unpredictable and depend on different parameters during curing. Epoxy material when reinforced with nanoparticles has got importance because of its extraordinary enhanced mechanical and thermal properties for structural application. Experimentally it is challenging to tailor these nanostructures and manufacture epoxy-based nanocomposites with desired properties. An experimental approach to preparing these is tedious and costly. The improvement of such materials requires huge experimentation and a better level of control of their properties can't be accomplished up till now. There is a need for numerical experimentation to guide these experimental procedures. With the headway of computational techniques, an alternative for these experiments had given an effective method to characterize these nanocomposites and study their reaction kinetics. Molecular dynamics (MD) simulation is one such technique that works on density function theory and Newton*s second law to characterize these materials with different permutations and combinations during their curing. This review is carried out for MD simulation studies done to date on different epoxies and epoxy-based nanocomposites for their thermal, mechanical, and thermo-mechanical characterization.","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70089858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3934/matersci.2023026
Worraphol Nansu, G. Ross, S. Ross, N. Suphrom, S. Mahasaranon
The major problem leading to substantial waste in the food industry is the spoilage of food products during transportation and storage periods. Consequently, the scope of this research focuses on the development and preparation a pH responsive monitoring films based on biodegradable materials of poly(vinyl alcohol) (PVA) and natural colorant extract from Caesalpinia sappan L. heartwood (SP). These monitoring films were prepared by a solution casting method and the film stability was improved by crosslinking with citric acid (CA). The red tone of monitoring film without CA was observed, while the crosslinked monitoring film showed a yellow color, which occurs from the structural change of brazilin (structure presenting in SP) to brazilein under acidic conditions. From the SEM and FTIR results, the monitoring film showed high compatibility between phases, improvements in light barrier properties and good WVTR performance. The tensile strength and elongation at break were slightly increased. For pH responsive properties, the monitoring films showed a high response with NH3 gas detection with the change in color from a yellow tone to a red tone. These results indicated that the monitoring films have potential to be applied as food packaging for meat, fish, pork, chicken, and other foods that generate ammonium gas during spoilage. Therefore, these high stable, and non-toxic biodegradable PVA films that incorporated with SP extract and crosslinked by CA have the potential to be used for food spoilage detection in packaging.
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