Present State of Liquid Phase Sintering

Kaysser, W. A.; Petzow, G.

doi:10.1179/pom.1985.28.3.145

“…This phenomenon have been widely studied in different works [16,17,18]. The use of copper at industrial level in sintered steels and all the problems linked with the transient liquid phase, boosted several fundamental studies associated with this kind of sintering option [19,20,21,22,23,24,25].…”

Section: First Alloying Elementsmentioning

confidence: 99%

“…This phenomenon have been widely studied in different works [16,17,18]. The use of copper at industrial level in sintered steels and all the problems linked with the transient liquid phase, boosted several fundamental studies associated with this kind of sintering option [19,20,21,22,23,24,25].The second important alloying element widely used in PM steels was nickel [26,27]. Nickel has, like Cu and compared with Fe, a low oxygen affinity, but it poor diffusivity in iron requieres the use of high sintering temperatures or long sintering times to get a proper diffusion into iron.…”

mentioning

confidence: 99%

From Sintered Iron to High Performance PM Steels

Torralba

¹

,

Oro

²

,

Campos

³

2011

MSF

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Keywords: powder metallurgy steels, low alloyed steels, high performance, master alloys.Abstract. Since low alloyed sintered steels were introduced in the market of the structural parts, we have followed the evolution of a material with poor mechanical properties and any uniformity (in the sense of reproducibility) to materials that today are produced with high reliability and performance. The working efficiency could be equivalent in many cases with the best wrought steel, and maintaining a good margin in terms of cost and competitively. In this paper a complete review of the topic is accomplished, from the early times when the first parts were made by plain iron or iron-carbon, going through the different alloying systems: Fe-Cu, Fe-P, Fe-Cu-Ni-Mo, and more recently Fe-Cr-Mo and Fe-Mn. The development in processing routes has been considered too. The main milestones in the field of new alloying systems have been: 1) the introduction of Cu in 60-70"s, 2) the new complex systems with Cu-Ni-Mo in the 80"s and 3) the introduction of alloying elements with high oxygen affinity (in the late 90"s). Regarding the milestones in processing could be considered: 1) the development of new mixing procedures, 2) the warm compaction and high velocity compaction, 3) the improvements in sintering control and high temperature sintering. Several decades of research and innovation, acting on the processing system (mixing, pressing, sintering, post-sintering operations,…) and on the alloying system (from the earliest times with plain iron to complex systems used today), has allowed us to have a highly competitive materials, in terms of performance, and processes in terms of cost. The future is still open to new developments. First sintered steels.Iron based powder metallurgy (PM), were developed in the previous years to the II World War, being the absence of raw materials the pushing effect, and it was the origin of a new materials family (PM Steels) that today can be considered a high performance materials. The first sintered part was introduced in the car industry by General Motors in 1937 and was an oil gear for oil pump [1]. One of the first components introduced was one iron part for an electrical engine in 1945 [2].Till late 60"s were manufactured by PM simple parts, that were based on Fe-C and Fe-Cu-C systems. The knowledge of these systems was developed from works that analyze the possible formation of liquid phase during sintering with the aim of improving the densification and to promote sintering activation [3] as well the diffusion mechanisms in plain systems and selfdiffusion of Fe [4,5]. To analyze and to understand the sintering steps were use iron wires that can reproduce the sintering model based on spheres [6].Looking for the improvement in the mechanical properties, at that time considering the available technology two basic requirements for new alloying systems were stated: poor or null affinity for the oxygen -sintering atmospheres were not enough dried [7]-and the possibility of controlling dimensionally the s...

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“…The contribution to the production of metallic parts by powder metallurgy is increased of consistent outline, supported for inestimable advantages. The list of benefits in the industrial processes of sintering is great and, not rare, surprises the coordinators of production of different industries that not yet had tried the technology and attend the explanation of specialists in the area [15][16][17][18]. The first one of the advantages is the cost reduction.…”

Section: Introductionmentioning

confidence: 99%

“…The first one of the advantages is the cost reduction. This project looked for to get systematically, in scale of laboratory, copper-nickel ternary alloys production by powder metallurgy, concerning the maintenance of the electric and mechanical properties with the purpose of getting electric connectors of high performance or high mechanical damping [14][15][16][17][18]. This work attempt to obtain systematic stages of the sintering and homogenization of the ternary copper nickel alloys utilizing powder metallurgy.…”

Section: Introductionmentioning

confidence: 99%

“…The aim of this work is to obtain metallic alloys with high mechanical strength and high electric conductivity after adequate optimization of sintering and thermal treatments (powder metallurgy) followed by structural, microstructural, electrical and mechanical characterization of Cu-y%Ni-x%Sn alloys (x and y has variable values in weight). Diverse types of products based on copper alloys can be manufactured through the process of powder metallurgy: porous, material filters, electric friction equipments, contacts and structural parts [14][15][16][17][18]. The alloy elements are added to copper with the intention to improve its resistance, ductility and thermal stability, without causing considerable damages on its form, electric and thermal conductivity and resistance to the corrosion, typical characteristic aspects of pure copper.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Microstructure and Microanalysis Studies of Copper-Nickel-Tin Alloys Obtained by Conventional Powder Metallurgy Processing

Monteiro

¹

,

Carrió

²

,

Masson

³

et al. 2010

MSF

3

0

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Abstract. The aim of this article was to analyze the microstructural development in samples of CuNi-Sn alloys (weight %) obtained by powder metallurgy (P/M). The powders were mixed for 1/2 hour. After this, they were pressed, in a cold uniaxial pressing (1000 kPa). In the next step the specimens were sintered at temperatures varying from 650 up to 780ºC under vacuum. Secondly, the samples were homogenized at 500 o C for several special times. The alloys were characterized by optical microscopy, electrical conductivity and Vickers hardness. X rays powder diffraction data were collected for the sintered samples in order to a structural and microstructural analysis. The comparative analysis is based on the sintered density, densification parameter, hardness, macrostructures and microstructures of the samples.

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Powder Metallurgy and Sintered Materials

Kaysser¹,

Weise

²

2000

Ullmann's Encyclopedia of Industrial Chemistry

3

1

0

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The article contains sections titled: 1. Introduction 1.1. Production Routes 1.2. Product Groups 1.3. History and Developments 1.4. Economic Aspects 2. Powder Production 2.1. Mechanical Methods 2.1.1. Mechanical Disintegration of Melts 2.1.2. Mechanical Disintegration of Solids 2.2. Physicochemical Methods 2.3. Chemical Methods 3. Powder Properties and Characterization 4. Powder Conditioning 5. Pressing and Forming at Ambient Temperatures 5.1. Uniaxial Pressing 5.2. Isostatic Pressing, Cold Rolling, and Extrusion 5.3. Pouring, Preforming, and Injection Molding 6. Sintering 6.1. The Sintering Process 6.1.1. Solid‐State Sintering 6.1.2. Liquid‐Phase Sintering 6.2. Sintering Furnaces and Atmospheres 7. Pressing and Shaping at Elevated Temperature 7.1. Hot Pressing and Hot Isostatic Pressing 7.2. Sinter Forging and other Methods 8. Structural Parts 8.1. Structural Ferrous Parts 8.1.1. Low‐Alloyed Steels 8.1.2. High‐Alloyed Steels 8.1.3. Secondary Operations 8.2. Copper and Copper Alloys 8.3. Aluminum and Aluminum Alloys 9. High‐Performance Materials 9.1. High‐Melting Metals and Alloys 9.2. Light Alloys 9.2.1. High‐Performance Aluminum Alloys 9.2.2. Titanium and Titanium Alloys 9.2.3. Magnesium and Beryllium 9.3. High‐Temperature Nickel and Cobalt Superalloys 9.4. Magnetic Materials 9.5. Hardmetals and Cermets 9.6. Metal ‐ Ceramic Composites 9.7. Electric Contact Materials 9.7.1. Contact Materials for Low‐Voltage Switchgear 9.7.2. Contact Materials for High‐Voltage Switchgear 10. Parts with Inherent, Functional Porosity

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Present State of Liquid Phase Sintering

Cited by 58 publications

References 5 publications

From Sintered Iron to High Performance PM Steels

From Sintered Iron to High Performance PM Steels

Microstructure and Microanalysis Studies of Copper-Nickel-Tin Alloys Obtained by Conventional Powder Metallurgy Processing

Powder Metallurgy and Sintered Materials

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