The effect of silicon nitride on the laser surface alloying with Fe-Cr-Si{sub 3}N{sub 4} powders

Journal Article · Mon May 01 04:00:00 EDT 1995 · Scripta Metallurgica et Materialia

DOI:https://doi.org/10.1016/0956-716X(95)00189-3· OSTI ID:64374

Huang, C C; Tsai, W T; Lee, J T ^[1]

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1. National Cheng Kung Univ., Tainan (Taiwan, Province of China). Dept. of Materials Science and Engineering

Laser surface alloying (LSA) is a process which can be utilized to modify the surface of a less expensive workpiece by producing a high performance alloy. N and Si alloying into stainless steel/carbon steel by LSA with Si{sub 3}N{sub 4}/Fe-Cr-Si{sub 3}N{sub 4} have been found to be feasible. Both hardness and corrosion resistance of steel could be improved by LSA. Concerning the corrosion resistance, however, the oxide in the LSAs might be detrimental to corrosion resistance. Fortunately, in the preparation of N and Si containing alloys, the presence of silicon nitride in the Fe-Cr-Si{sub 3}N{sub 4} mixed powders provide the additional advantage of reducing oxidation during LSA. This reduction of oxidation phenomenon had been suggested to occur by the decrease of partial pressure of O{sub 2} in consequence of the formation of N{sub 2} resulting from decomposition of silicon nitride during LSA. On the other hand, a lower dilution of the alloying elements in the alloys prepared with Fe-Cr-Si{sub 3}N{sub 4} powders, compared to the alloys prepared with Fe-Cr powders, has also been found. This might be attributed to a portion of the laser energy being consumed for the decomposition of silicon nitride resulting in less energy for melting and less dilution of surface alloy elements. With Si{sub 3}N{sub 4} in the mixed powders, however, the absorption of the incident laser beam (10.6 {mu}m wavelength) increases. More dilution of alloying elements in the LSAs would be expected to occur with greater laser energy absorbed. Both phenomena of less oxidation and less dilution of the alloying elements in the alloys prepared with Fe-Cr-Si{sub 3}N{sub 4} powders have already been reported. However, the mechanism involving these two phenomena still remains unclear. In this study, the interesting effect of silicon nitride on these two phenomena of the LSA with Fe-Cr0Si{sub 3}N{sub 4} is examined.

• OSTI ID: 64374
• Journal Information: Scripta Metallurgica et Materialia, Journal Name: Scripta Metallurgica et Materialia Journal Issue: 9 Vol. 32; ISSN 0956-716X; ISSN SCRMEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
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CARBON DIOXIDE LASERS
CARBON STEELS
CHEMICAL ANALYSIS
CHROMIUM ALLOYS
COMPOSITE MATERIALS
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POWDERS
SILICON ALLOYS
SILICON NITRIDES
SPECTROSCOPY
SURFACE COATING