Hot wire configuration for depositing device grade nano-crystalline silicon at high deposition rate

Laser cladding by cold-wire feeding is known as an efficient cladding method due to its advantages, such as near 100% material utilization, high deposition rate, and flexible adaptation to the cladding position. However, it has very stringent requirements on the operative conditions, such as a small range of wire feeding rate and precise wire feeding position. The aim of this work was to investigate the laser hot-wire cladding technique, which improved the productivity and stability of the process significantly with respect to laser cold-wire cladding. The external preheating of the filler wire resulted in reduction in required laser power, a low dilution, and a higher deposition rate. A comparison was made between laser cold-wire cladding and laser hot-wire cladding of Inconel 625 on mild steel, with respect to the clad characteristics, microstructure, and hardness. An optimization of the main processing parameters in laser hot-wire cladding, such as the laser power, laser spot size, laser scanning speed, wire feeding orientation and position, wire preheating voltage, and wire feeding rate, was performed. The optimal parameters were used to create a multi-track deposit.

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Open circuit voltage improvement of high-deposition-rate microcrystalline silicon solar cells by hot wire interface layers

Applied Physics Letters ◽

10.1063/1.2011771 ◽

2005 ◽

Vol 87 (7) ◽

pp. 073503 ◽

Cited By ~ 76

Author(s):

Y. Mai ◽

S. Klein ◽

R. Carius ◽

H. Stiebig ◽

X. Geng ◽

...

Keyword(s):

Solar Cells ◽

Deposition Rate ◽

Open Circuit Voltage ◽

Open Circuit ◽

Silicon Solar Cells ◽

High Deposition Rate ◽

Hot Wire ◽

Microcrystalline Silicon ◽

Interface Layers

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Comparison of Hardness and Microstructures Produced Using GMAW and Hot-Wire TIG Mechanized Welding of High Strength Steels

Volume 14: Emerging Technologies; Engineering Management, Safety, Ethics, Society, and Education; Materials: Genetics to Structures ◽

10.1115/imece2014-36482 ◽

2014 ◽

Author(s):

A. R. H. Midawi ◽

E. B. F. Santos ◽

A. P. Gerlich ◽

R. Pistor ◽

M. Haghshenas

Keyword(s):

Weld Metal ◽

Deposition Rate ◽

Heat Input ◽

Gas Metal Arc Welding ◽

High Strength Steels ◽

Travel Speed ◽

Pressure Vessels ◽

High Deposition Rate ◽

Hot Wire ◽

Wire Feed

For high productivity weld fabrication, gas metal arc welding (GMAW) is typically used since it offers a combination of high deposition rate and travel speed. Recent advances in power supply technologies have increased the deposition rates in hot-wire tungsten inert gas (HW-TIG) welding, such that it is possible to achieve parameters which may be comparable to those used in GMAW for pressure vessels and some pipeline applications. However, these two processes have drastically different deposition efficiencies and heat input characteristics. The purpose of the present study is to examine GMAW and HW-TIG bead-on-plate deposits in terms of mechanical properties, deposition rate, and heat affected zone (HAZ) thermal cycles when identical travel speed and wire feed speeds are applied with a ER90S-G filler metal. The results demonstrate that HW-TIG can be applied with comparable travel and wire feed speeds to GMAW, while providing a more uniform weld bead appearance. Based on weld metal microhardness values, it is suggested the effective heat input is lower in HW-TIG compared to GMAW, since the average hardness of the weld metal is slightly higher.

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Performances of Nano/Amorphous Silicon Films Produced by Hot Wire Plasma Assisted Technique

MRS Proceedings ◽

10.1557/proc-507-607 ◽

1998 ◽

Vol 507 ◽

Cited By ~ 6

Author(s):

I. Ferreira ◽

H. Águas ◽

L. Mendes ◽

F. Fernandes ◽

E. Fortunato ◽

...

Keyword(s):

Amorphous Silicon ◽

Transport Properties ◽

Oxygen Content ◽

Hydrogen Content ◽

Crystalline Silicon ◽

Silicon Films ◽

Hot Wire ◽

Hydrogen Dilution ◽

Nano Crystalline ◽

Doped Silicon

ABSTRACTThis work reports on the performances of undoped and n doped amorphous/nano-crystalline silicon films grown by hot wire plasma assisted technique. The film's structure (including the presence of several nanoparticles with sizes ranging from 5 nm to 50 nm), the composition (oxygen and hydrogen content) and the transport properties are highly dependent on the filament temperature and on the hydrogen dilution. The undoped films grown under low r.f. power (≍ 4 mWcm−2) and with filament temperatures around 1850 °K have dark conductivities below 10−1Scm−1, optical gaps of about 1.5 eV and photo-sensitivities above 105, (under AM3.5), with almost no traces of oxygen content. N- doped silicon films were also fabricated under the same conditions which attained conductivities of about 10−2Scm−1.

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