Sputter deposition of a corrosion-resistant amorphous metallic coating
- PDF / 5,158,998 Bytes
- 10 Pages / 593.28 x 841.68 pts Page_size
- 37 Downloads / 209 Views
INTRODUCTION Low-carbon steels, such as 1008 steel, are commonly used in automotive applications because of their many desirable mechanical properties. However, due to the lack of alloying elements like Cr and Ni, these steels can be subject to rapid deterioration in corrosive environments. One solution to prevent degradation is a corrosion-resistant coating. This article describes the characterization of sputter deposited coatings from a Metglas® alloy 2826A target onto 1008 steel. We have found we can successfully sputter a coating that improves the corrosion resistance of mild steel in both basic and acidic solutions. We will also show that the composition and morphology and, hence, the corrosion resistance of the sputtered film, depend critically on the choice of sputtering parameters. w Allied Chemical Metglas® alloy 2826A (Fe 32 Ni3 6 Cr 14 P 12 B 6 ) is a highly corrosion-resistant amorphous metal in basic and acidic environments.3"8 The alloy is prepared in the amorphous state by rapidly cooling the melt onto a rotating copper wheel. However, due to the thin ribbon geometry that results, its practical application is very limited. As other workers have shown, to utilize this alloy's high corrosion resistance more effectively, films of this alloy were deposited by
a>
Present address: Hydro-Quebec Research Institute, Varennes, Quebec, Canada.
862
J. Mater. Res. 3 (5), Sep/Oct 1988
http://journals.cambridge.org
various methods and onto a variety of substrates.9 12 In this work thin films of Metglas® were sputter deposited onto a highly corrosive substrate, a conventionally processed low-C steel. Sputter deposition, a technique for which the effective quench rate is generally considered to be many orders of magnitude greater than that obtained by melt quenching,13'14 was chosen as the technique to deposit the films to assure the possibility of an amorphous coating. Others15"24 have shown that magnetron sputtering can be used successfully to make corrosion-resistant amorphous coatings and, when available, this approach may sometimes be the preferred method of deposition. Using rf sputtering, we report success in preparing films that largely maintain our alloy's composition and also provide a protective coating for mild steel. II. EXPERIMENTAL PROCEDURE Substrates for sputter deposition were punched out as 16 mm disks from sheets of 1008 steel and polished with silicon carbide paper down to 600 grit, followed by a final polish with 1 /urn diamond paste. Some were subsequently polished to a 0.05 /im finish, although an actual surface roughness measurement was not made. The substrates were cleaned with acetone, trichloroethene, and # 3 0 alcohol prior to deposition. Carbon-coated copper grids and silicon wafers were also used as substrates for transmission electron microscopy (TEM), scanning electron microscopy (SEM), x-ray diffraction
0003-6951 /88/050862-10$01.75
Downloaded: 08 Apr 2015
© 1988 Materials Research Society
IP address: 203.64.11.45
Lee, Fisher, and Schulz: Sputter deposition of a metallic c
Data Loading...
