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Applications
Published in Pramod K. Naik, Vacuum, 2018
Vacuum furnaces are employed for various applications such as brazing, sintering, heat treatment/annealing, degassing and carburizing. In a vacuum furnace the components assemblies to be thermally processed are surrounded by vacuum. The presence of
Surface morphology transformation and densification behaviour of conventionally sintered AlFeCoNiSi high entropy alloys
Published in Powder Metallurgy, 2023
Sheetal Kumar Dewangan, Cheenepalli Nagarjuna, Hansung Lee, Ashutosh Sharma, Byungmin Ahn
The X-ray Diffraction (XRD) was carried out on a mechanically alloyed metal powder to investigate the phase characteristics with a Rigaku instrument (with a Cu radiation target). The XRD experiment was conducted under the operating conditions of 40 kV and 40 mA. The samples were scanned in a range of diffraction angles between 30° and 80° at a scan speed of 3°/min in 0.02° steps. Further, the microstructure of the alloyed powder was revealed by the scanning electron microscope (SEM, JSM-7100F Jeol, Japan). The compaction process was performed in a hydraulic press under a pressure of 20 MPa and the holding time was 1 min. The compacted sample was sintered in a vacuum furnace in an argon environment for 1 h at a temperature of 700°C. Further, sintering was also performed at 800°C, 900°C and 1000°C for 1 h. The processed sample was re-tested by the XRD and SEM. Energy dispersive spectrometry (EDS) was also performed for the composition analysis. In addition, experimental density has been calculated by the Archimedes principle.
A critical review of copper electroless deposition on glass substrates for microsystems packaging applications
Published in Surface Engineering, 2022
Bajpai et al. [152] investigated the impact of thermal annealing on the adhesion strength of the electrodeposited copper film on the electroless deposited seed layer of nickel. Glass was first cleaned using a soap solution. Electroless deposition of nickel was conducted using a conventional two-step sensitization (SnCl2) and activation (PdCl2). A nickel seed layer of 20 nm was deposited in 2 min with an electroless bath at a temperature of 70°C. After electroless deposition, a copper layer of 1 µm thickness was electrodeposited on the seed layer using 15 mA cm–2 current density. The samples were then transferred to the vacuum furnace for thermal annealing for 30 min at a temperature of 240°C. A ramp-up heating and ramp-down cooling rates of 5 and 4°C min–1, respectively, were used. A peel-off test was conducted on the glass samples, and the results are shown in Figure 21.
Laser power effects on properties of laser brazing diamond coating
Published in Surface Engineering, 2020
Weimin Long, Dashuang Liu, Xian Dong, Aiping Wu
In recent years, the methods for manufacturing single-layer diamond tools have received much attention. The main methods are brazing in a vacuum furnace and induction heating brazing [4–7]. However, both methods have their own shortcomings. Brazing in a vacuum furnace has a lower production efficiency, and the diamond grits will be exposed to high temperature for a long time, which will cause severe thermal damage to the diamond grits and affect their quality. The limitations of high-frequency induction brazing are mainly the complicated design and manufacture of the coil and the heating range is affected by the shape of the coil [8,9]. Since the laser beam energy with its inherently higher efficiency makes the extent of thermal damage of the diamond grits, and the thermal deformation of the substrate during the laser brazing process better controlled, this method of selecting laser beam for brazing can not only solve the deficiencies in the above two processes, but also obtain a machining tool with good grinding performance [10,11].