Effect of hot pressing variables on the microstructure, relative density and hardness of sterling silver (Ag-Cu alloy) powder compacts

Henriques, Bruno; Soares, Delfim; Teixeira, José Carlos; Silva, Filipe

doi:10.1590/s1516-14392014005000022

Cited by 9 publications

(6 citation statements)

References 4 publications

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“…Microwave sintered sample also reported that hardly reveal any development and cobalt does not exhibit any dissolution of tungsten while there are nearly 20% dissolved in cobalt binder phase in the conventional sintering. The researcher also found that sample that sintered in microwave always showed improvement in mechanical properties compared to the conventional sintered one [34].…”

Section: Microwave Sinteringmentioning

confidence: 94%

“…When using the hot pressing method, some of the ceramic materials are found to be densified even at lower temperature when compared to conventional method. The benefits in using hot pressing sintering technique are firstly improving the densification kinetic and limited of grain development, where disadvantages are the end product have limited geometry and equipment needed highly in cost [34].…”

Section: Conventional Sinteringmentioning

confidence: 99%

“…Spark Plasma Sintering or in a more complex Pulsed Electric Current Sintering (PECS) is a new technology in the field of metals, ceramics and composite fabrication starting from powders. With the nanostructured features, it has the potential of densifying powders while avoid it become rough which follow the densification routes [34]. This spark plasma sintering mechanism has been investigated in the 1960s and began to be used in metal powder compressed.…”

Section: Spark Plasma Sinteringmentioning

confidence: 99%

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Conventional Sintering Effects on the Microstructure and Electrical Characteristics of Low-Voltage Ceramic Varistor

Ghazali¹,

Shaifudin²,

Abdullah³

et al. 2018

Sintering Technology - Method and Application

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Conventional, free or pressure less sintering is the simplest technique which involves heating of a powder compact, previously prepared at ambient temperatures, without applying any external pressure. It can be conducted with various box furnaces or tube furnaces under different atmospheres (oxidizing, reducing, inert, and vacuum). Through the use of this method, a highly applicable varistor can be mass produced. Varistors are of a particular interest for modern surge protection of over-voltage. Nowadays, ZnO ceramic varistors are most favorable in electronic industry due to their excellent electrical characteristics and high energy handling capabilities. By optimizing the method during sintering process, the number of potential barriers formed can be controlled thus improving the capability of the low-voltage varistor.

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Section: Microwave Sinteringmentioning

confidence: 94%

Section: Conventional Sinteringmentioning

confidence: 99%

Section: Spark Plasma Sinteringmentioning

confidence: 99%

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Conventional Sintering Effects on the Microstructure and Electrical Characteristics of Low-Voltage Ceramic Varistor

Ghazali¹,

Shaifudin²,

Abdullah³

et al. 2018

Sintering Technology - Method and Application

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“…One way to increase the density of powder blanks is to use re-deformation operations, which include the static final squeezing, stamping, isostatic and dynamic hot pressing, as shown in works [1,2]. The method of static hot pressing is a variant of cold static pressing; it actually combines pressing and baking of the workpiece by heating at a temperature above the recrystallization temperature of the powder material [3]. The disadvantages of this method are low performance, as well as low resistance of graphite press equipment, which limits its use in manufacturing.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Determining the influence exerted by the static conditions of final squeezing on the compaction process of iron-based powder materials

Minitsky

Minitska

Okhrimenko

et al. 2021

EEJET

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This paper reports a study into the process of re-compaction of powder briquettes in the conditions of static pressing at a pressure of 800 MPa. The technological parameters of the pressing process have been analyzed, which make it possible to improve the compaction of powder briquettes based on iron. Such parameters are the outer greasing, which reduces friction between a green compact and the walls of the press tool matrix, and the firing, which removes the deformation strengthening of the green compacts and increases their plasticity. The green compacts’ sealing mechanism involved in the final squeezing process has been established, which is associated with the grinding of pre-compressed particles due to the strain in the contact areas. The increase in the stressed state of green compacts following the final squeezing was confirmed by the results of studying the residual micro-strains. The change in the stressed state of iron green compacts has been confirmed by the study into the structurally sensitive characteristics, which include the materials’ magnetic and electrical properties. Determining the magnetic characteristics has shown that final squeezing leads to an increase in coercive force, which can be explained by both the increase in the stressed state and the grinding of grains. Investigating the impact exerted by the annealing environment on the value of magnetic characteristics has demonstrated that annealing in hydrogen is more effective in terms of improving magnetic properties than annealing in a vacuum. This is due to the refining of grain boundaries through the processes of reduction of oxide films. The study of the mechanical characteristics of green compact materials based on iron powder has established that final squeezing leads to an increase in the hardness and strength of materials depending on the conditions of deformation. A significant improvement in the green compacts’ strength (820‒824 MPa) is due to both a decrease in porosity by 8‒10 % and an increase in the contact area as a result of plastic deformation after the annealing

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“…Generally, second phase is added to improve the arc extinguishing performance of the contact or improve the viscosity of the molten pool to reduce the melt splashing. In recent years, many researchers have modified the microstructure and electrical contact properties of Cu alloys by adding different elements (W, Ni, Ag, Ce, Y, Cr) 1,5,12,15,16 or oxides (CdO, SnO 2 , CeO 2 ) 9,11,17 . Among these, the action of some oxides is more significant and effective to electrical contact properties than that of elements.…”

Section: Introductionmentioning

confidence: 99%

Contrastive Research on Electrical Contact Performance for Contact Materials of Cu-SnO2 and Cu-ZnO2 Alloys

et al. 2019

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Herein, SnO 2 -and ZnO 2 -doped (1.5 wt.%) composite Cu powder was prepared by mechanical alloying (MA) respectively, and both the contact materials of oxide-doped Cu alloys were subsequently obtained by canned hot-pressing powder sintering with hot extrusion combined. Scanning electron microscopy (SEM), laser scanning confocal microscopy (LSCM) and self-designed electrical breakdown device were used for investigating the microstructure and properties including electric conductivity and hardness, especially for electrical contact performance of the Cu-SnO 2 alloy and in compared with the Cu-ZnO 2 alloy. The experimental results show that the hardness of Cu-SnO 2 and Cu-ZnO 2 contact materials are 103.5±1 HV and 192.7±1 HV, respectively, which meet the hardness standard of national standard electrical contact materials. Meanwhile, the relative conductivity %IACS are 7.24% and 6.20%, respectively, which are higher than the traditional Cu-based contact materials. This electrical life simulation test system was designed independently, and the results indicate that the switching times of Cu-SnO 2 contact materials are much more than that of Cu-ZnO 2 . The addition of SnO 2 can effectively improve the arc extinguishing characteristics and the anti-welding performance of the contact materials is enhanced. In summary, SnO 2 -doped Cu-based contact materials possess excellent comprehensive properties, which can provide reference for potential applications in contact materials.

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Effect of hot pressing variables on the microstructure, relative density and hardness of sterling silver (Ag-Cu alloy) powder compacts

Cited by 9 publications

References 4 publications

Conventional Sintering Effects on the Microstructure and Electrical Characteristics of Low-Voltage Ceramic Varistor

Conventional Sintering Effects on the Microstructure and Electrical Characteristics of Low-Voltage Ceramic Varistor

Determining the influence exerted by the static conditions of final squeezing on the compaction process of iron-based powder materials

Contrastive Research on Electrical Contact Performance for Contact Materials of Cu-SnO2 and Cu-ZnO2 Alloys

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