Wear and corrosion properties of mechanically coated 316 stainless Steel-TiC nanocomposites

Abstract

The mechanical coating (MC) method was used to deposit 316 stainless steel (SS316), TiC, and SS 316-TiC nanocomposite coatings on SS 316 substrates using a ball mill machine at milling durations of 1, 2, 5, 10, and 15 h using relatively cheap and abundant raw material. The chemical composition of the SS 316, TiC, and SS 316-xTiC (x = 20, 50, 80 wt%) nanocomposite coatings deposited by the mechanical coating method has been investigated and the hardness values and the wear and corrosion mechanisms were presented. Dense and uniform coatings were obtained using a ball-to-powder weight ratio (BPR) of 20:1 and an MC duration of 5 h. Among the samples, the SS316-20 wt%TiC coating exhibited the best wear and corrosion resistance. The least mean coefficient of friction was 0.3 for the SS316-20 wt%TiC deposited sample while the largest mean coefficient was for the SS316-80 % TiC sample to be 0.76. The SS 316-20 wt% TiC sample had the lowest wear rate where the highest value was for the %100SS 316 sample being 0.36 × 10 −6 and 19 × 10 −6 (mm 3 /Nm), respectively. Corrosion tests revealed that the SS316-20%TiC sample had the best corrosion resistance among the composite samples having a corrosion resistance of 4.9358 μm/Y. The corrosion resistance decreased with the increase of TiC whereas the 80 % TiC coating had severe pitting. Cracks and pores present in the non-uniform 100 % TiC coating resulted in lower corrosion resistance compared to the 100 % SS 316 and composite coatings. • Nanostructured TiC, SS 316, and SS 316-TiC composite coatings were prepared by mechanical coating technique using a planetary high energy ball mill on an SS 316 substrate. The mechanical coating duration of 5 h was shown to be the optimum time which decreased the crystallite size to nanosize while with higher milling times some cracks were formed at the coating substrate interface. • It has been shown that the powder mixture composition severely affects the coating properties, wear resistance, and corrosion resistance. • Moreover, the lowest wear rate was obtained for the 20 % TiC coated sample to be around 0.36 × 10 −6 which is more than 50 times resistant than the 100 % SS 316 sample. • The Tafel test showed that the introduction of TiC as reinforcement improved the corrosion resistance. • The increase of TiC content from 20 to 50 and 80 wt% caused an increase in the current density and corrosion rate. • The 20 % TiC sample had the highest corrosion resistance and its corrosion rate was 3.5 times less than the 80 % TiC sample.

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