ABSTRACT
Carburization is a promising surface-hardening approach to maximize the tribological and mechanical properties of metals and alloys by making thin-layer surface carbides. The current study investigates the effect of carburizing on the electrodeposited Fe-W alloy coating. This process involeves the thermal decomposition of ethanol in an argon (Ar) atmosphere at varying temperatures. The amorphous electrodeposits of Fe-W alloy coating formed at optimized current density (500 A/cm2) are transformed to the uniform W-rich reinforced bimetallic carbide (Fe3W3C) layers at a carburizing temperature of 850 °C. The sample Fe-50WC (850 °C) shows enhanced hardness and highest wear resistance with a lowest specific wear rate (10-7 mm3/Nm) as compared to the as-electrodeposited Fe-W alloy and other Fe-W, Co-W, and hard chromium coatings reported in the literature. The present strategy can be applied to develop alternative, low cost, and environmentally friendly W-based composite coatings to replace the toxic chromium coatings.
ABSTRACT
The objective of the current experiment was to determine the effects of sodium bicarbonate (SBC) and chromium propionate (Cr) supplementation on dry matter intake (DMI), growth performance, blood indices, feed sorting behavior, and digestibility of nutrients during the hot and humid condition in Beetal bucks. Twenty-eight Beetal bucks were randomly assigned to four concentrates treatments (n = 7 bucks/treatment) under 2 × 2 factorial arrangements. The factors were (1) chromium supplementation, basal diet without any supplementation (C) and basal diet with Cr @ 1.5 mg Cr/head/day (Cr), and (2) sodium bircbonate supplementation, basal diet supplemented with SBC @15 g/kg of DM (SBC) and diet containing SBC @ 15 g/kg of DM) and Cr @ 1.5 mg/day/animal (SBC + Cr). Chromium was drenched to each animal during the morning feeding. The average daily noon temperature-humidity index (THI) was 86.37 ± 4.01. The daily DMI and ADG was higher (P < .0001) in the SBC, and trend for daily DMI was observed (P < 0.01) for the Cr. The feed to gain ratio was tended to improve (P = 0.056) by the supplementation of Cr. Plasma glucose, cholesterol, and catalase concentration were lower (P < 0.05) in the Cr supplemented, whereas plasma BUN and TPP were not influenced (P > 0.05) by the Cr or the SBC supplementation. The feed selection index indicated that supplementation of Cr and SBC had no effects on selection or rejection of feed particles. In Cr-supplemented bucks, there was a trend for higher ADF digestibility. Digestibility of dry matter, organic matter, NDF, and ADF were not affected by Cr or SBC supplementation. In conclusion, co supplementation of Cr @ 1.5 mg/d and SBC @ 15 g/kg resulted in highest DMI, ADG and improved the feed efficiency in heat-stressed fattening bucks by alleviating negative impacts of HS.
