Pub Date : 2019-04-03DOI: 10.5772/INTECHOPEN.82382
Shih-Ying Chang, Yan-Hua Huang, L. Tsao
Due to the relatively high stability of ceramic surfaces, ceramics, graphite, and alloys that easily form an oxide passivation layer by natural oxidation, such as aluminum alloys, titanium alloys, and magnesium alloys, are not wetted by common solders and brazing fillers. Moreover, in most applications, the brazing temperature is so high that it causes hot cracking or functional degradation of the difficult-to-wet materials. Active filler metals containing active elements have been developed, which can successfully join the nonwetting materials at low temperatures (<250°C) in air. The active elements, such as titanium, magnesium, and rare earth elements, in active solders play an important role in wettability and reactivity between filler metals and difficult-to-wet materials. Solders with active element content have been shown to provide excellent wettability. Hence, direct active soldering has been developed to simplify the manufacturing of difficult-to-wet material joints. A prac-tical understanding of the design and characterization of low melting point active solders and active soldering processes is elaborated in this chapter. The effects of active elements, active solder characteristics, mechanism of active soldering, active soldering techniques, and specific applications are introduced. The influence of the thermal and mechanical activation on the interfacial reactions between filler metals and difficult-to-wet materials during the active soldering process is also discussed.
{"title":"Active Solders and Active Soldering","authors":"Shih-Ying Chang, Yan-Hua Huang, L. Tsao","doi":"10.5772/INTECHOPEN.82382","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.82382","url":null,"abstract":"Due to the relatively high stability of ceramic surfaces, ceramics, graphite, and alloys that easily form an oxide passivation layer by natural oxidation, such as aluminum alloys, titanium alloys, and magnesium alloys, are not wetted by common solders and brazing fillers. Moreover, in most applications, the brazing temperature is so high that it causes hot cracking or functional degradation of the difficult-to-wet materials. Active filler metals containing active elements have been developed, which can successfully join the nonwetting materials at low temperatures (<250°C) in air. The active elements, such as titanium, magnesium, and rare earth elements, in active solders play an important role in wettability and reactivity between filler metals and difficult-to-wet materials. Solders with active element content have been shown to provide excellent wettability. Hence, direct active soldering has been developed to simplify the manufacturing of difficult-to-wet material joints. A prac-tical understanding of the design and characterization of low melting point active solders and active soldering processes is elaborated in this chapter. The effects of active elements, active solder characteristics, mechanism of active soldering, active soldering techniques, and specific applications are introduced. The influence of the thermal and mechanical activation on the interfacial reactions between filler metals and difficult-to-wet materials during the active soldering process is also discussed.","PeriodicalId":310487,"journal":{"name":"Fillers - Synthesis, Characterization and Industrial Application","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115016544","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 : 2019-04-03DOI: 10.5772/INTECHOPEN.82889
D. Obada, Laminu Shettima Kuburi, D. Dodoo‐Arhin, Yongdan Hou, M. B. Balogun, M. Muhammad
This chapter describes an experimental investigation into the dynamic mechanical properties of coir and coconut husk particulate reinforced polymer composites which were prepared by the hot press method. The composite was immersed in a strongly acidic environment of pH 2.2 for a period of 14 and 28 days (14P and 28P). Values of storage modulus at different vibrational frequencies recorded for the polymers at low temperatures where the molecules are still tightly compressed and the region of first solid state transitions are: Control sample (CS ) —913.18, 984.18 and 979.94 MPa; 14P—505.54, 492.47 and 473.60 MPa and 28P—282.25, 298.70 and 285.36 MPa at 2, 5 and 10 Hz, respectively. While values of loss modulus at different vibrational frequencies are: CS—113.32, 109.43 and 107.62 MPa, 14P—92.92, 92.92 and 101.93 MPa and 28P—46.08, 45.61 and 45.18 MPa at 2, 5 and 10 Hz, respectively. Degradation of the mechanical properties was ascribed to the penetration and absorption that occurred between the acid solution and the composite constituents (matrix, filler, and fiber). It was found that frequency variation influenced the dynamic mechanical properties of the polymer composite at the points of measurement.
{"title":"Dynamic Mechanical Behaviour of Coir and Coconut Husk Particulate Reinforced Polymer Composites: The Effect of Exposure to Acidic Environment","authors":"D. Obada, Laminu Shettima Kuburi, D. Dodoo‐Arhin, Yongdan Hou, M. B. Balogun, M. Muhammad","doi":"10.5772/INTECHOPEN.82889","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.82889","url":null,"abstract":"This chapter describes an experimental investigation into the dynamic mechanical properties of coir and coconut husk particulate reinforced polymer composites which were prepared by the hot press method. The composite was immersed in a strongly acidic environment of pH 2.2 for a period of 14 and 28 days (14P and 28P). Values of storage modulus at different vibrational frequencies recorded for the polymers at low temperatures where the molecules are still tightly compressed and the region of first solid state transitions are: Control sample (CS ) —913.18, 984.18 and 979.94 MPa; 14P—505.54, 492.47 and 473.60 MPa and 28P—282.25, 298.70 and 285.36 MPa at 2, 5 and 10 Hz, respectively. While values of loss modulus at different vibrational frequencies are: CS—113.32, 109.43 and 107.62 MPa, 14P—92.92, 92.92 and 101.93 MPa and 28P—46.08, 45.61 and 45.18 MPa at 2, 5 and 10 Hz, respectively. Degradation of the mechanical properties was ascribed to the penetration and absorption that occurred between the acid solution and the composite constituents (matrix, filler, and fiber). It was found that frequency variation influenced the dynamic mechanical properties of the polymer composite at the points of measurement.","PeriodicalId":310487,"journal":{"name":"Fillers - Synthesis, Characterization and Industrial Application","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131092221","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 : 2018-12-19DOI: 10.5772/INTECHOPEN.81727
E. Karaogul, Ertuğrul Altuntaş, T. Salan, M. Alma
The main aim of this chapter is to indicate the importance of additives and modifications used for PVA/starch biohybrid films. The additives and modifications used to improve the mechanical, thermal, and morphological properties of films are plasticizers, cross-linkers, fillers, physical and chemical treatment, and natural materials as well as thermoplastic starch. Plasticizers are preferred for higher molecular dynamism because of flexibility of functional groups in PVA and starch. Their flexibility is considerably affected by carboxyl and hydroxyl groups of plasticizers. The use of cofunctional groups increases the plasticity, flexibility, and physicochemical and mechanical properties of films. Moreover, cross-linking modifications are also effective to enhance the properties of biofilms. These modifications improve the tensile strength, modulus of elasticity, water resistance, thermal resistance, swelling behavior, and antibacterial activity of films. Fillers are also used to enhance the properties of PVA/starch films. In this way, the properties such as gas barrier, mechanical stiffness, transparency and thermal stability of the filler-added films are improved. The chemical and physical modifications provide stronger hydrogen bonds in films due to increasing carboxyl groups. Thus, the physical, biological, and chemical properties of films are improved because of the changing molecular structure via esterification, etherification, hydrogen bonding, and oxidation. etherification, hydrogen bonding, and oxidation in their molecular structure.
{"title":"The Effects of Novel Additives Used in PVA/Starch Biohybrid Films","authors":"E. Karaogul, Ertuğrul Altuntaş, T. Salan, M. Alma","doi":"10.5772/INTECHOPEN.81727","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.81727","url":null,"abstract":"The main aim of this chapter is to indicate the importance of additives and modifications used for PVA/starch biohybrid films. The additives and modifications used to improve the mechanical, thermal, and morphological properties of films are plasticizers, cross-linkers, fillers, physical and chemical treatment, and natural materials as well as thermoplastic starch. Plasticizers are preferred for higher molecular dynamism because of flexibility of functional groups in PVA and starch. Their flexibility is considerably affected by carboxyl and hydroxyl groups of plasticizers. The use of cofunctional groups increases the plasticity, flexibility, and physicochemical and mechanical properties of films. Moreover, cross-linking modifications are also effective to enhance the properties of biofilms. These modifications improve the tensile strength, modulus of elasticity, water resistance, thermal resistance, swelling behavior, and antibacterial activity of films. Fillers are also used to enhance the properties of PVA/starch films. In this way, the properties such as gas barrier, mechanical stiffness, transparency and thermal stability of the filler-added films are improved. The chemical and physical modifications provide stronger hydrogen bonds in films due to increasing carboxyl groups. Thus, the physical, biological, and chemical properties of films are improved because of the changing molecular structure via esterification, etherification, hydrogen bonding, and oxidation. etherification, hydrogen bonding, and oxidation in their molecular structure.","PeriodicalId":310487,"journal":{"name":"Fillers - Synthesis, Characterization and Industrial Application","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125883967","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 : 2018-11-05DOI: 10.5772/INTECHOPEN.81708
Qi Wang, Kexin Chen, Wenbin Cao
Micro-sized spherical AlN particles have presented great commercial potential as thermally conductive fillers for high-performance thermal interface materials, benefiting from their high thermal conductivity and good fluidity in the polymers. In this chapter, recent research progress in the carbothermal synthesis of spherical AlN fillers is highlighted. The influences of various synthetic parameters, includ-ing N 2 gas pressure, additive content, additive particle size, reaction temperature, reaction time, carbon content, and additive types, on the nitridation rate and the particle size and morphology of final AlN powders are summarized. More impor-tantly, the growth mechanism of micro-sized spherical AlN granules is deeply discussed as well.
{"title":"Carbothermal Synthesis of Spherical AlN Fillers","authors":"Qi Wang, Kexin Chen, Wenbin Cao","doi":"10.5772/INTECHOPEN.81708","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.81708","url":null,"abstract":"Micro-sized spherical AlN particles have presented great commercial potential as thermally conductive fillers for high-performance thermal interface materials, benefiting from their high thermal conductivity and good fluidity in the polymers. In this chapter, recent research progress in the carbothermal synthesis of spherical AlN fillers is highlighted. The influences of various synthetic parameters, includ-ing N 2 gas pressure, additive content, additive particle size, reaction temperature, reaction time, carbon content, and additive types, on the nitridation rate and the particle size and morphology of final AlN powders are summarized. More impor-tantly, the growth mechanism of micro-sized spherical AlN granules is deeply discussed as well.","PeriodicalId":310487,"journal":{"name":"Fillers - Synthesis, Characterization and Industrial Application","volume":"131 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121402181","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}
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