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Arcing Contact Materials
Published in Paul G. Slade, Electrical Contacts, 2017
The silver refractory metal contact materials can be made by a wide variety of powder metallurgical techniques. Since the vast majority of the materials are made by one of three basic processes, the manufacturing technology discussion will be limited to the basic differences and characteristics for these three methods. The three methods are shown in Figure 16.1, all under Process D; (1.0) press sinter repress (PRS), (2.0) liquid phase sintering (LPS), and (3.0) infiltration. More recently a fourth process, hot isostatic pressing (HIP), is being used in combination with the basic three processes to increase density. For more detailed information on general powder metallurgy techniques including, HIP, liquid phase sintering, and infiltration, “Powder Metallurgical Science” by R. German may be useful [76]. It should be understood that saying that only three general processing techniques are used does not imply that the individual processes are the same for different companies. Although two companies, for example, have processes that fit the general description for infiltration, the process steps and controls for the individual steps may vary significantly. In order to make the discussion of the three processes easier, a description of the general processing for silver tungsten will be discussed for the three techniques.
A Comprehensive Review of Design and Development of Advanced Tailored Material on Sustainability Aspects
Published in Sarbjeet Kaushal, Ishbir Singh, Satnam Singh, Ankit Gupta, Sustainable Advanced Manufacturing and Materials Processing, 2023
Saurabh Rai, Subodh Kumar, Ankit Gupta
In the stacking process, there should be spatial distribution of the materials with height. The compressing or compacting step mold made by powder with the required composition of the powder distribution provides strength to the mold for further processing of the part (Saxena et al. 2019). The compacted part is then taken for the sintering process. The sintering process is used to create bonds between materials; the packed powder is heated below the melting point, typically two-thirds to three-fourths of the melting point of powder material. Hot isostatic pressing (HIP), pressureless sintering, hot press, and spark plasma sintering are all options for sintering (SPS) (Heimann 2007).
Product Quality
Published in G.K. Awari, C.S. Thorat, Vishwjeet Ambade, D.P. Kothari, Additive Manufacturing and 3D Printing Technology, 2021
G.K. Awari, C.S. Thorat, Vishwjeet Ambade, D.P. Kothari
As mentioned earlier, hot isostatic pressing (HIP) is a process that uses high temperatures and high gas over pressures to heat a part to a temperature below melting and at pressures of 100s of MPa, and temperatures in the range of 900–1000°C for 2 to 4 hours to help close and fuse internal pores, voids, and defects. HIP can also provide heat treatment benefits by optimizing the temperature and pressure cycles to improve mechanical properties such as strength, elongation, ductility, and to improve the structural integrity of the component. The equipment is large and costly and may require a specialty service provider.
Effect of hot isostatic pressing treatment on porosity reduction and mechanical properties enhancement of 316L stainless steel fabricated by binder jetting
Published in Virtual and Physical Prototyping, 2023
Yiwei Mao, Jiaming Yuan, Yuhua Heng, Kunhao Feng, Daosheng Cai, Qingsong Wei
Hot isostatic pressing (HIP) is a technique that applies high isostatic pressure (hundreds of MPa) to a closed object through an inert gas at a high temperature (Atkinson and Davies 2000). High temperature and high pressure during the HIP process can accelerate the sintering of powders by overcoming the surface-energy driving force for pore closure. Therefore, HIP can homogenise the microstructure, reduce porosity, and in turn improve strength (Teng et al. 2022; Cai et al. 2021). HIP was initially used to consolidate loose powders and later widely used for post-processing castings(Atkinson and Davies 2000). Recently, the HIP technique has also been widely used in additively manufactured parts, such as electron beam melting (Tammas-Williams et al. 2016), laser powder bed fusion (Sun et al. 2021), and cold spray additive manufacturing (Chen et al. 2019).