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Different Hardness Sol-gel Surface Treatment of A390 Aluminium Alloy and its Tribological Effects

Research Article Open Access
John Presin Kumar1* and R. Rajavel2
1Mechanical Engineering Department, Singhania University, Pacheri Bari, Distt, Jhunjhunu (Rajasthan), India
2Mechanical Engineering Department, International City, Manipal University, Dubai-345050, UAE
*Corresponding authors: John Presin Kumar
Mechanical Engineering Department
Singhania University, Pacheri Bari, Distt
Jhunjhunu (Rajasthan), India
E-mail: jpk_1977@yahoo.co.in
 
Received January 02, 2012; Published July 26, 2012
 
Citation: Kumar JP, Rajavel R (2012) Different Hardness Sol-gel Surface Treatment of A390 Aluminium Alloy and its Tribological Effects. 1: 177. doi:10.4172/scientificreports.177
 
Copyright: © 2012 Kumar JP, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
 
Abstract
 
In this work, the suitability of aluminium A390 for bearing application is analyzed by means of sol-gel surface coating of Chromium nitrate Cr(NO3)3 of different hardness values. A380 is better known for its application as aluminium bearing material but it is little more costlier than A390. Therefore the ways in which A390 can be improved in properties like A380 is worked out in this work and sol-gel treatment technology associated with dip coating is utilized as the surface treatment technique. Wear loss and Specific Wear Rate analysis are done for these materials for comparing A390 with A380. In terms of specific wear rate, it is found that A390 hardened to 55 HRC has equivalent properties to A380 and cost effective.
 
Keywords
 
Sol-gel; SEM; EDAX; XRD; AFM; Pin-on-disc
 
Introduction
 
Aluminium alloys should possess better wear resistance and anti friction properties especially those used for bearing applications. Where is the removal of the material from the surface of a solid body as a result of mechanical action of the counter body. A380 and A390 are important aluminium related bearing alloys which finds many conventional usage for the same. Chromium nitrate Cr(NO3)3 is selected as the coating material for A390 alloy because of its anti-wear properties. In sol-gel technology, the coating material is first synthesized and then coated on the material using dip-coating for different hardness values such as 55HRC, 65 HRC etc using variations in heat treatment furnace temperature, aging time duration etc. Wear test is done using pin-ondisc apparatus and the specific wear rate results are compared for both the alloys (Table 1).
 
Table 1: Symbolic Name for the Different Specimens Used.
 
Methodology
 
Aluminium alloys A390 and A380 are compared for tribological behavior after surface modifications using different hardness sol-gel treatment.
 
Wear Testing
 
The pin-on-disc apparatus wear tests are done in three trials in order to incorporate the various changes in heat treatment furnace temperature, aging time duration etc. These tests were carried out at a constant load of 3 kg and a sliding velocity of 3 m/s with different sliding distances of 250 m, 500 m and 1000 m keeping other parameters constant and the results are presented in the tables below. Secondly wear tests were carried out for a constant sliding distance of 1000 m with a sliding velocity of 2 m/s and under various load conditions of 2.5 kg, 5 kg and 10 kg.
 
Conclusions
 
The dry sliding wear behavior was studied on aluminium alloys for bearing application in this work. In overall, A390 Hardened to 55 HRc (C1 specimens) performs better than untreated specimen and also A380 alloy but its performance is less compared to A390 Hardened to 60 HRc (C2 specimens) (Table 2). A390 hardened to 55 HRc is found to be equivalent to A380 and cost effective. The SEM examination suggests that the mechanism of material removal is due to plastic deformation. In detail, The reducing agent called Poly Vinyl Alcohol (PVA) (Table 3-5) proved to be a better reducing agent.
 
Table 2: Symbolic Name for the Different Specimens Used.
 
Table 3: Reducing agent called Poly Vinyl Alcohol (PVA), Temperature of size reduction 210°C, Aging time duration of 8 hours, Temperature of heat treatment of the order of 800°C, Time duration of 5 hours inside the furnace, Particle size of coating material of 180nm, Aging time duration of 10 hours, Temperature inside the furnace of 350°C for dip coating, Time duration inside the furnace of the order of 7 hours.
 
Table 4: Reducing agent called Poly Vinyl Alcohol (PVA), Temperature of size reduction 210°C, Aging time duration of 8 hours, Temperature of heat treatment of the order of 800°C, Time duration of 5 hours inside the furnace, Particle size of coating material of 180nm, Aging time duration of 10 hours, Temperature inside the furnace of 350°C for dip coating, Time duration inside the furnace of the order of 7 hours.
 
Table 5: Reducing agent called Poly Vinyl Alcohol (PVA), Temperature of size reduction 210°C, Aging time duration of 8 hours, Temperature of heat treatment of the order of 800°C, Time duration of 5 hours inside the furnace, Particle size of coating material of 180nm, Aging time duration of 10 hours, Temperature inside the furnace of 350°C for dip coating, Time duration inside the furnace of the order of 7 hours.
 
• Temperature of size reduction 210°C before aging showed to be the proper temperature.
 
• Aging time duration of 8 hours seemed to be better over other values.
 
• Temperature of heat treatment of the order of 800°C was the perfect one.
 
• Time duration of 5 hours inside the furnace for heat treatment proved to be ideal.
 
• Particle size of coating material of 180 nm promised to be best.
 
• Aging time duration of 10 hours was the correct value over other possible durations.
 
• Temperature inside the furnace of 350°C for dip coating seemed to be giving better results.
 
Time duration inside the furnace of the order of 7 hours proved to be best out of all other values.
 
 
References