Thermal Stability and Lubrication Properties of Biodegradable Castor Oil on AISI 4140 Steel

Abstract

Lubricants have much importance in several industries, principally serving to reduce friction and wear in mechanical elements. In this study, the influence of Castor oil as bio-lubricant on the friction and wear performance of AISI 4140 steel was investigated. For that purpose, pin-on-disk friction tests were conducted according to ASTM G-99, by using pins of tungsten carbide (WC) as counterparts. The experiments were performed at two different temperatures. This work also presents the Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR) and 1 H-NMR analyses for the chemical characterization of oils and a study of their degradation by oxidation. The analysis of the damage caused to steel due to friction was deepened by analyzing its microhardness and microstructure in the worn zone. As a reference, the same experiments were performed with a commercial oil. The friction behavior of 4140 steel/WC with Castor oil lubrication at the two temperatures was notably better than that obtained under the reference oil lubrication. The kinetic friction coefficient (µ k) was up to 76% lower. However, a slight increase in steel wear was observed under Castor oil lubrication. Despite this, these results suggest that Castor oil could be used as bio-lubricant in systems which are susceptible to levels of high friction.

Improvement Effect of Green Lubricants on the Tribological and Mechanical Performance of 4140 Steel

“…The minimum film thickness can be obtained by the equations of B. J. Hamrock and D. Dowson [18] for point contacts, as applied in [6]. For that purpose, the values of the pressure-viscosity coefficient (α p ) of the lubricants are required.…”

“…Green lubricants exhibit low toxicity, excellent biodegradability, and, usually, they are derived from natural vegetable oils [2,5]. The most commonly employed natural oils for producing bio-based lubricants are rapeseed, sunflower, canola, soybean, palm, coconut, and castor oil, to name a few [1,2,[5][6][7][8]. Generally, vegetable oils have excellent lubricating properties, and they also present high viscosity indexes (VI) and high flash points [2,5,8].…”

Optimization of ethanolic transesterification ultrasound‐assisted from oil mixtures utilizing Box‐Behnken design

“…Thus, it is interesting that the legume that produces a limited amount of oil and is produced on small farms should be used in the production of biodiesel. For example, castor seed presents high oil content, ranging from 44% to 60% of dry mass and has the characteristics of large amplitude of thermal conditions and high oxidative stability . Similarly, the peanut seed is very promising for biodiesel production, because it presents a high oil content of 45% to 55% .…”

“…For example, castor seed presents high oil content, ranging from 44% to 60% of dry mass 10 and has the characteristics of large amplitude of thermal conditions and high oxidative stability. 11 Similarly, the peanut seed is very promising for biodiesel production, because it presents a high oil content of 45% to 55%. 12,13 These two seeds, castor and peanut, are produced in family farming, and their use in biodiesel production would lead to significant additions to the financial and economic value of the vegetal culture in semiarid areas of Brazil.…”

Enhanced Ricinoleic Acid Preparation Using Lipozyme TLIM as a Novel Biocatalyst: Optimized by Response Surface Methodology

“…Ricinoleic acid (RA), also known as cis-12-hydroxy-9-octadecenoic acid, is the only industrial fatty acid containing a hydroxy group in nature [1] and can be used as raw material for skin care products, plasticizers, emulsifiers, lubricants, and nanomaterials [2][3][4][5][6][7][8]. Castor oil (CO) is one kind of nonedible oil derived from the plant seeds of Ricinus communis [1,9].…”