Pub Date : 2023-10-01DOI: 10.2320/matertrans.mt-c2023007
Yukino Mori, Yoshikatsu Nishida, Hiromasa Shoji
The corrosion behavior and resistance of hot-dip galvanized steel were studied in a saturated Ca(OH)2 aqueous solution containing chloride ions (Cl−) in concrete. In the saturated Ca(OH)2 aqueous solution, which simulated water in the concrete pores, Ca(Zn(OH)3)2·2H2O was formed on the surface of the hot-dip galvanized steel, acting as a protective film. However, the corrosion rate of zinc increased as the Cl− concentration increased. This is presumed to be owing to the formation of Zn5(OH)8Cl2·H2O and CaCO3 on the surface and the decrease in the coverage of the protective film Ca(Zn(OH)3)2·2H2O. However, in concrete, the corrosion of hot-dip galvanized steel was not promoted by the cyclic corrosion test. This may be because the Cl− that penetrated into the concrete did not reach the depth of the galvanized steel and the Ca(Zn(OH)3)2·2H2O that was formed during the curing of the concrete remained after the cyclic corrosion test.
{"title":"The Research of Corrosion Mechanism of Galvanized Steel in Concrete","authors":"Yukino Mori, Yoshikatsu Nishida, Hiromasa Shoji","doi":"10.2320/matertrans.mt-c2023007","DOIUrl":"https://doi.org/10.2320/matertrans.mt-c2023007","url":null,"abstract":"The corrosion behavior and resistance of hot-dip galvanized steel were studied in a saturated Ca(OH)2 aqueous solution containing chloride ions (Cl−) in concrete. In the saturated Ca(OH)2 aqueous solution, which simulated water in the concrete pores, Ca(Zn(OH)3)2·2H2O was formed on the surface of the hot-dip galvanized steel, acting as a protective film. However, the corrosion rate of zinc increased as the Cl− concentration increased. This is presumed to be owing to the formation of Zn5(OH)8Cl2·H2O and CaCO3 on the surface and the decrease in the coverage of the protective film Ca(Zn(OH)3)2·2H2O. However, in concrete, the corrosion of hot-dip galvanized steel was not promoted by the cyclic corrosion test. This may be because the Cl− that penetrated into the concrete did not reach the depth of the galvanized steel and the Ca(Zn(OH)3)2·2H2O that was formed during the curing of the concrete remained after the cyclic corrosion test.","PeriodicalId":18402,"journal":{"name":"Materials Transactions","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135323629","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}
Suppressed hydrogen peroxide (H2O2) generation and practical H2 oxidation reaction (HOR) activity of the anode catalyst surface is crucial to improve proton exchange membrane fuel cells (PEMFCs) performance. Here, the influence of surface modification on H2O2 generation and HOR activity by introducing tungsten suboxides (WOx) was investigated for platinum catalyst surfaces. A Pt(111) single-crystal substrate surface was used as the model of Pt-nanoparticle anode catalyst surface and modified with WOx through the reactive arc plasma deposition (APD) of W under an O2 partial pressure (p(O2) = 1 × 10−1 or 10−3 Pa). The oxidation states of WOx were estimated by X-ray photoelectron spectroscopy, and the resulting electrocatalytic properties of H2O2 generation and HOR activity were investigated using a scanning electrochemical microscope. The as-prepared oxidation states of WOx were modified depending on p(O2) during the APD. Contrarily, potential cycle (PC) loadings resulted in a similar oxidation state of WOx: substoichiometric oxides containing W4+ or W5+, irrespective of the as-prepared oxidation states of the deposited tungsten. Regardless of the WOx oxidation state, the WOx/Pt(111) surfaces exhibited suppressed H2O2 generation, even accompanied by enhanced HOR activity compared with the clean Pt(111). Therefore, the WOx surface modification can improve the properties of Pt-based anode catalysts and contribute to high-performance catalyst developments.
{"title":"Suppressed Hydrogen Peroxide Generation and Enhanced Electrochemical Hydrogen Oxidation Activity for Tungsten-Oxide-Modified Platinum Surface Model Catalyst System","authors":"Kenta Hayashi, Hikaru Kamikawa, Naoto Todoroki, Toshimasa Wadayama","doi":"10.2320/matertrans.mt-mh2022004","DOIUrl":"https://doi.org/10.2320/matertrans.mt-mh2022004","url":null,"abstract":"Suppressed hydrogen peroxide (H2O2) generation and practical H2 oxidation reaction (HOR) activity of the anode catalyst surface is crucial to improve proton exchange membrane fuel cells (PEMFCs) performance. Here, the influence of surface modification on H2O2 generation and HOR activity by introducing tungsten suboxides (WOx) was investigated for platinum catalyst surfaces. A Pt(111) single-crystal substrate surface was used as the model of Pt-nanoparticle anode catalyst surface and modified with WOx through the reactive arc plasma deposition (APD) of W under an O2 partial pressure (p(O2) = 1 × 10−1 or 10−3 Pa). The oxidation states of WOx were estimated by X-ray photoelectron spectroscopy, and the resulting electrocatalytic properties of H2O2 generation and HOR activity were investigated using a scanning electrochemical microscope. The as-prepared oxidation states of WOx were modified depending on p(O2) during the APD. Contrarily, potential cycle (PC) loadings resulted in a similar oxidation state of WOx: substoichiometric oxides containing W4+ or W5+, irrespective of the as-prepared oxidation states of the deposited tungsten. Regardless of the WOx oxidation state, the WOx/Pt(111) surfaces exhibited suppressed H2O2 generation, even accompanied by enhanced HOR activity compared with the clean Pt(111). Therefore, the WOx surface modification can improve the properties of Pt-based anode catalysts and contribute to high-performance catalyst developments.","PeriodicalId":18402,"journal":{"name":"Materials Transactions","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135323649","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}
Pub Date : 2023-10-01DOI: 10.2320/matertrans.mt-m2023049
Wataru Tasaki, Yuya Arai, Shuichi Miyazaki, Hee Young Kim
Novel Ni–Ti–Zr–Hf–Nb and Ni–Ti–Zr–Hf–Ta high temperature shape memory alloys with multi-principal elements were developed, and differences in the effects of Nb and Ta on cold workability and shape memory properties were investigated. Constituent phases, microstructure, cold workability, transformation temperatures, shape memory properties were investigated in (Ni50Ti30Zr10Hf10)100−xNbx (x = 5, 10, 15) alloys and (Ni50Ti30Zr10Hf10)100−yTay (y = 5, 10, 15) alloys. Although both of Nb and Ta were effective to improve cold workability of Ni50Ti30Zr10Hf10 alloy by forming a ductile β phase with a disordered body-centered cubic structure, it was found that Ta was more effective than Nb in improving cold workability. The addition of Ta was also effective to suppress the formation of Ti2Ni-type intermetallic compound. Transformation temperatures were not significantly affected by the addition of Nb, while the transformation temperatures increased by the addition of Ta. According to thermal cycling tests, the (Ni50Ti30Zr10Hf10)85Nb15, (Ni50Ti30Zr10Hf10)90Ta10 and (Ni50Ti30Zr10Hf10)85Ta15 alloys exhibited almost full shape recovery under 200 MPa. These alloys are suggested as promising candidates for practical high temperature shape memory alloys that can be worked at room temperature.
{"title":"Development of Ni–Ti–Zr–Hf–(Nb, Ta) Multi-Principal Element High-Temperature Shape Memory Alloys with High Cold Workability","authors":"Wataru Tasaki, Yuya Arai, Shuichi Miyazaki, Hee Young Kim","doi":"10.2320/matertrans.mt-m2023049","DOIUrl":"https://doi.org/10.2320/matertrans.mt-m2023049","url":null,"abstract":"Novel Ni–Ti–Zr–Hf–Nb and Ni–Ti–Zr–Hf–Ta high temperature shape memory alloys with multi-principal elements were developed, and differences in the effects of Nb and Ta on cold workability and shape memory properties were investigated. Constituent phases, microstructure, cold workability, transformation temperatures, shape memory properties were investigated in (Ni50Ti30Zr10Hf10)100−xNbx (x = 5, 10, 15) alloys and (Ni50Ti30Zr10Hf10)100−yTay (y = 5, 10, 15) alloys. Although both of Nb and Ta were effective to improve cold workability of Ni50Ti30Zr10Hf10 alloy by forming a ductile β phase with a disordered body-centered cubic structure, it was found that Ta was more effective than Nb in improving cold workability. The addition of Ta was also effective to suppress the formation of Ti2Ni-type intermetallic compound. Transformation temperatures were not significantly affected by the addition of Nb, while the transformation temperatures increased by the addition of Ta. According to thermal cycling tests, the (Ni50Ti30Zr10Hf10)85Nb15, (Ni50Ti30Zr10Hf10)90Ta10 and (Ni50Ti30Zr10Hf10)85Ta15 alloys exhibited almost full shape recovery under 200 MPa. These alloys are suggested as promising candidates for practical high temperature shape memory alloys that can be worked at room temperature.","PeriodicalId":18402,"journal":{"name":"Materials Transactions","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135323363","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}
Pub Date : 2023-10-01DOI: 10.2320/matertrans.mt-mh2022007
Hiroyuki Saitoh
This paper describes high-pressure synthetic studies on novel hydrides. High-pressure hydrogenation experiments are carried out using a cubic-type multi-anvil apparatus. In-situ synchrotron radiation X-ray diffraction measurements are effectively used to explore synthetic conditions, to investigate the reaction mechanisms, and to characterize the thermodynamic stabilities of the obtained hydrides. Theoretical calculations based on first-principles calculations enable us to predict the thermal stability and crystal structure of the target hydrides before the high-pressure experiments, which leads to the rapid discovery of the novel hydrides. Lithium-containing hydrides, YLiFeH6, LiNiH3, Li4FeH6, and Li3AlFeH8 are synthesized. Syntheses of aluminum-based alloys hydrides, Al2CuH and Al3FeH4 under high-pressure are also described. These results demonstrate that the high-pressure technique is useful for discovering novel hydrides.
{"title":"Syntheses of Novel Hydrides Containing Light Elements under High Pressure and High Temperature","authors":"Hiroyuki Saitoh","doi":"10.2320/matertrans.mt-mh2022007","DOIUrl":"https://doi.org/10.2320/matertrans.mt-mh2022007","url":null,"abstract":"This paper describes high-pressure synthetic studies on novel hydrides. High-pressure hydrogenation experiments are carried out using a cubic-type multi-anvil apparatus. In-situ synchrotron radiation X-ray diffraction measurements are effectively used to explore synthetic conditions, to investigate the reaction mechanisms, and to characterize the thermodynamic stabilities of the obtained hydrides. Theoretical calculations based on first-principles calculations enable us to predict the thermal stability and crystal structure of the target hydrides before the high-pressure experiments, which leads to the rapid discovery of the novel hydrides. Lithium-containing hydrides, YLiFeH6, LiNiH3, Li4FeH6, and Li3AlFeH8 are synthesized. Syntheses of aluminum-based alloys hydrides, Al2CuH and Al3FeH4 under high-pressure are also described. These results demonstrate that the high-pressure technique is useful for discovering novel hydrides.","PeriodicalId":18402,"journal":{"name":"Materials Transactions","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135323364","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}
Pd-loaded perovskite composite manganese oxide (Pd/AMnO3, A = Ca, Sr, La) catalysts were prepared by coprecipitation method, in order to reveal metal-support interaction (MSI). Particulate PdO with sizes of a few ten nanometers were randomly formed on CaMnO3. On the other hand, fibrous PdO with diameter approximately 20 nm was formed on LaMnO3. Both shape of PdO were formed on SrMnO3. HAXPES measurement showed a down shift of valence band of deposited PdO depending on the composite manganese oxide. Our characterization indicates that the MSI at Pd–AMnO3 interface affects not only the shape but the electronic structure of deposited PdO on AMnO3. The CO oxidation activity was in order of Pd/LaMnO3 > Pd/SrMnO3 > Pd/CaMnO3, which corresponds to the order of the PdO valence band shift trend. We proposed that the observed correlation between the valence band shift and the CO oxidation activity for Pd/AMnO3 can be understood in terms of the CO adsorption strength.
采用共沉淀法制备了负载Pd的钙钛矿复合氧化锰(Pd/AMnO3, A = Ca, Sr, La)催化剂，以揭示金属-载体相互作用(MSI)。在CaMnO3上随机形成了几十纳米大小的PdO颗粒。另一方面，在LaMnO3上形成直径约20 nm的纤维状PdO。两种形状的PdO均在SrMnO3上形成。HAXPES测量表明，沉积的PdO的价带随复合氧化锰的不同而下降。我们的表征表明，Pd-AMnO3界面的MSI不仅影响沉积在AMnO3上的PdO的形状，而且影响其电子结构。CO的氧化活性依次为Pd/LaMnO3 > Pd/SrMnO3 > Pd/CaMnO3，与PdO的价带移位趋势一致。我们提出，观察到的价带位移与Pd/AMnO3的CO氧化活性之间的相关性可以用CO吸附强度来理解。
{"title":"Metal-Support Interaction at Palladium-Composite Manganese Oxide Interface and CO Oxidation Activity","authors":"Toyokazu Tanabe, Kazuma Aso, Shugoro Tsutsumi, Seiya Shimono, Saburo Hosokawa","doi":"10.2320/matertrans.mt-mh2022012","DOIUrl":"https://doi.org/10.2320/matertrans.mt-mh2022012","url":null,"abstract":"Pd-loaded perovskite composite manganese oxide (Pd/AMnO3, A = Ca, Sr, La) catalysts were prepared by coprecipitation method, in order to reveal metal-support interaction (MSI). Particulate PdO with sizes of a few ten nanometers were randomly formed on CaMnO3. On the other hand, fibrous PdO with diameter approximately 20 nm was formed on LaMnO3. Both shape of PdO were formed on SrMnO3. HAXPES measurement showed a down shift of valence band of deposited PdO depending on the composite manganese oxide. Our characterization indicates that the MSI at Pd–AMnO3 interface affects not only the shape but the electronic structure of deposited PdO on AMnO3. The CO oxidation activity was in order of Pd/LaMnO3 > Pd/SrMnO3 > Pd/CaMnO3, which corresponds to the order of the PdO valence band shift trend. We proposed that the observed correlation between the valence band shift and the CO oxidation activity for Pd/AMnO3 can be understood in terms of the CO adsorption strength.","PeriodicalId":18402,"journal":{"name":"Materials Transactions","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135323626","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 effectiveness of a corrosion repair technique consisting of laser cleaning and cold spraying was investigated. The effect of laser pulse frequency on the removal of surface corrosion on steel specimens was analyzed. Subsequently, a zinc coating was cold-sprayed on specimens cleaned of surface corrosion using conventional disc grinder and laser methods. Furthermore, salt spray tests were conducted to compare the corrosion protection performance of the zinc coating on these specimens. The results showed that laser cleaning can effectively remove surface corrosion and that a laser pulse frequency of 15 kHz is more effective than that of 40 kHz for removing the surface oxide layer. A comparison of cold-sprayed zinc coatings on laser-cleaned and non-treated specimens indicated that surface oxidation during laser treatment may negatively affect zinc deposition efficiency. The zinc coating on the laser-cleaned specimen was more than twice as thick as that on the conventionally cleaned specimen, and the coating–specimen interface maintained good adhesion after a 168 h salt spray test. Although no corrosion was observed in both steel specimens after the salt spray test, cracking of the remaining corroded areas on the substrate and delamination of the coating occurred in the conventionally cleaned specimen.
{"title":"Suggestion of a New Repair Technique for Steel Structures by Low-Pressure Cold Spray and Laser Cleaning","authors":"Tomonori Hatori, Hiroki Saito, Yuji Ichikawa, Kazuhiro Ogawa, Yuichi Kato, Kosaku Motomura, Michito Nakano, Norimichi Yamashita","doi":"10.2320/matertrans.mt-t2023001","DOIUrl":"https://doi.org/10.2320/matertrans.mt-t2023001","url":null,"abstract":"The effectiveness of a corrosion repair technique consisting of laser cleaning and cold spraying was investigated. The effect of laser pulse frequency on the removal of surface corrosion on steel specimens was analyzed. Subsequently, a zinc coating was cold-sprayed on specimens cleaned of surface corrosion using conventional disc grinder and laser methods. Furthermore, salt spray tests were conducted to compare the corrosion protection performance of the zinc coating on these specimens. The results showed that laser cleaning can effectively remove surface corrosion and that a laser pulse frequency of 15 kHz is more effective than that of 40 kHz for removing the surface oxide layer. A comparison of cold-sprayed zinc coatings on laser-cleaned and non-treated specimens indicated that surface oxidation during laser treatment may negatively affect zinc deposition efficiency. The zinc coating on the laser-cleaned specimen was more than twice as thick as that on the conventionally cleaned specimen, and the coating–specimen interface maintained good adhesion after a 168 h salt spray test. Although no corrosion was observed in both steel specimens after the salt spray test, cracking of the remaining corroded areas on the substrate and delamination of the coating occurred in the conventionally cleaned specimen.","PeriodicalId":18402,"journal":{"name":"Materials Transactions","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135323631","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}
Pub Date : 2023-10-01DOI: 10.2320/matertrans.mt-mg2022026
Nguyen Dang Co, Bui Dai Phat, Phan Van Khai, Tran Quang Dat, Ho Thi Anh, Nguyen Tran Ha, Le Viet Cuong, Nguyen Huy Tiep, Nguyen Thi Minh Hong, Dang Duc Dung, Ngo Duc Quan, Tran Mau Danh, Phan The Long, Pham Duc Thang, Bui Dinh Tu
The combination of two dielectric-magnetic components in the same composite has been shown to significantly improve the effectiveness of electromagnetic (EM) shielding and microwave absorption (MWA) because they have both a combination of high dielectric and magnetic losses and good impedance matching. The novel Bi1/2(Na0.8K0.2)1/2TiO3/Fe3O4 (BNKT/Fe3O4) composite has been successfully synthesized by a two-step method with wide effective absorption bandwidth (EAB = 16 GHz) in the high-frequency (2–18 GHz). It was evident that the MWA efficiency of the BNKT/Fe3O4 composite has been significantly improved compared with pure Bi1/2(Na0.8K0.2)1/2TiO3 or Fe3O4 materials. In addition, the BNKT/Fe3O4 composite could achieve reflection loss (RL = −39.41 dB, ∼99.99% at 10.16 GHz) with a sample thickness optimal (d = 4.7 mm). This work shows that the novel BNKT/Fe3O4 composite has excellent MWA properties, all contributing to a potential candidate in the electromagnetic wave absorption and shielding fields.
{"title":"Synthesis and Microwave Absorption Properties of Novel Bi<sub>1/2</sub>(Na<sub>0.8</sub>K<sub>0.2</sub>)<sub>1/2</sub>TiO<sub>3</sub>/Fe<sub>3</sub>O<sub>4</sub> Composite","authors":"Nguyen Dang Co, Bui Dai Phat, Phan Van Khai, Tran Quang Dat, Ho Thi Anh, Nguyen Tran Ha, Le Viet Cuong, Nguyen Huy Tiep, Nguyen Thi Minh Hong, Dang Duc Dung, Ngo Duc Quan, Tran Mau Danh, Phan The Long, Pham Duc Thang, Bui Dinh Tu","doi":"10.2320/matertrans.mt-mg2022026","DOIUrl":"https://doi.org/10.2320/matertrans.mt-mg2022026","url":null,"abstract":"The combination of two dielectric-magnetic components in the same composite has been shown to significantly improve the effectiveness of electromagnetic (EM) shielding and microwave absorption (MWA) because they have both a combination of high dielectric and magnetic losses and good impedance matching. The novel Bi1/2(Na0.8K0.2)1/2TiO3/Fe3O4 (BNKT/Fe3O4) composite has been successfully synthesized by a two-step method with wide effective absorption bandwidth (EAB = 16 GHz) in the high-frequency (2–18 GHz). It was evident that the MWA efficiency of the BNKT/Fe3O4 composite has been significantly improved compared with pure Bi1/2(Na0.8K0.2)1/2TiO3 or Fe3O4 materials. In addition, the BNKT/Fe3O4 composite could achieve reflection loss (RL = −39.41 dB, ∼99.99% at 10.16 GHz) with a sample thickness optimal (d = 4.7 mm). This work shows that the novel BNKT/Fe3O4 composite has excellent MWA properties, all contributing to a potential candidate in the electromagnetic wave absorption and shielding fields.","PeriodicalId":18402,"journal":{"name":"Materials Transactions","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135323647","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}
Resistance spot welding is used in the assembly of automobile bodies. The use of high tensile strength steel plates in automobile bodies is expanding, and there is a need to develop a welding process that improves the joint strength per resistance spot weld point. To improve the joint strength per resistance spot weld, resistance spot welding can be combined with other joining methods, such as the WeldBond method. As an additional joining method around the nugget, other than using adhesives as in the WeldBond method, brazing can be used to obtain a strong joint without melting the base metal. In this paper, it was proposed that the joint strength can be enhanced by using resistance spot welding and brazing or soldering based on the rule of mixture. And, based on this concept, effect of additional joint around a nugget, such as brazing or soldering, on rotational deformation of joint part and tensile shear strength of resistance spot welded lap joint was examined.
{"title":"Effect of Combined Use of Brazing or Soldering around the Nugget on Tensile Shear Strength of Resistance Spot Welded Lap Joint","authors":"Takanori Kitamura, Tetsuya Akiyama, Atsuro Uemura, Chinatsu Mihara","doi":"10.2320/matertrans.mt-m2023096","DOIUrl":"https://doi.org/10.2320/matertrans.mt-m2023096","url":null,"abstract":"Resistance spot welding is used in the assembly of automobile bodies. The use of high tensile strength steel plates in automobile bodies is expanding, and there is a need to develop a welding process that improves the joint strength per resistance spot weld point. To improve the joint strength per resistance spot weld, resistance spot welding can be combined with other joining methods, such as the WeldBond method. As an additional joining method around the nugget, other than using adhesives as in the WeldBond method, brazing can be used to obtain a strong joint without melting the base metal. In this paper, it was proposed that the joint strength can be enhanced by using resistance spot welding and brazing or soldering based on the rule of mixture. And, based on this concept, effect of additional joint around a nugget, such as brazing or soldering, on rotational deformation of joint part and tensile shear strength of resistance spot welded lap joint was examined.","PeriodicalId":18402,"journal":{"name":"Materials Transactions","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135063171","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}
Multinary Cu2ZnSnS4 (CZTS)-based materials have attracted considerable attention for thermoelectric (TE) power generation owing to their cost-effectiveness and abundance. The device structure of the CZTS/Au diffusion barrier layer was effective in impeding chemical diffusion during operation; however, its interfacial contact resistance was relatively higher than that of the Bi2Te3 device. We report the discovery of p-type CZTS single crystals with a record-high dimensionless figure of merit (ZT) of 1.6 at 800 K and TE conversion efficiency of ∼4% at a temperature difference of 473 K, which is based on the Te-free concept. This study demonstrated the potential of CZTS-based TE materials for environment-friendly TE power generation.
{"title":"Thermoelectric Conversion Efficiency of 4% in Environmental-Friendly Kesterite Single Crystal","authors":"Akira Nagaoka, Katsuma Nagatomo, Koki Nakashima, Yuichi Hirai, Yasuyuki Ota, Kenji Yoshino, Kensuke Nishioka","doi":"10.2320/matertrans.mt-e2023002","DOIUrl":"https://doi.org/10.2320/matertrans.mt-e2023002","url":null,"abstract":"Multinary Cu2ZnSnS4 (CZTS)-based materials have attracted considerable attention for thermoelectric (TE) power generation owing to their cost-effectiveness and abundance. The device structure of the CZTS/Au diffusion barrier layer was effective in impeding chemical diffusion during operation; however, its interfacial contact resistance was relatively higher than that of the Bi2Te3 device. We report the discovery of p-type CZTS single crystals with a record-high dimensionless figure of merit (ZT) of 1.6 at 800 K and TE conversion efficiency of ∼4% at a temperature difference of 473 K, which is based on the Te-free concept. This study demonstrated the potential of CZTS-based TE materials for environment-friendly TE power generation.","PeriodicalId":18402,"journal":{"name":"Materials Transactions","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135323628","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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