OBRABOTKAMETALLOV TECHNOLOGY Vol. 24 No. 3 2022 this material has a high wear rate. A group of researchers attempted to improve the wear resistance of PTFE material by reinforcing it with different fi llers, considering its wide range of automotive applications having sliding contact [1-5]. Sonawane et al. [1] observed better sliding wear properties for 35% carbon fi ber fi lled PTFE material against 25% carbon fi lled PTFE when using Al6061 as countersurface. AISI 304 is the most used austenitic stainless steel in household, automotive and industrial applications. With a view to consider PTFE composite as an alternative material for automotive applications, Chinchanikar et al. [2] performed dry sliding wear characteristics of PTFE composite reinforced with carbon fi ber (35 wt.%) against AISI 304 stainless steel. Their study observed development of transfer fi lmwith increase in pressure at sliding interfaces that assisted in decreasing specifi c wear rate. However, further studies are required on the development of transfer fi lm on the sliding surface considering the effect of normal load, sliding velocity, and temperature. Unal et.al. [3] investigated the wear of PTFE, PTFE+17% glass fi ber, PTFE+25% bronze, PTFE+35% carbon fi ber. Their study found a decrease in friction coeffi cient for the PTFE and composites up to a certain normal load beyond which friction and wear rate increased. Their investigation observed the formation of thin and uniform transfer fi lm in the case of PTFE and disruption of transfer fi lm in the case of bronze- and carbon-fi lled composite. Sachin [4] studied the wear behavior of PTFE and its composites including glass and carbon as fi ller. Their study observed an increase in volume loss with the increase in load and distance. However, volume loss decreased with the increase in grit size and was considered to be a dominant factor for the wear resistance of the materials. Their study showed that carbon-fi lled composites had greater wear resistance than fi berglass-reinforced PTFE matrix. Venkateswarlu et al. [5] investigated mechanical properties such as hardness, tensile strength, and elongation of pure PTFE and different PTFE-composites with varying fi ller concentrations. Their study observed an increase in hardness with the optimum fi ller content and beyond this value hardness was decreased. On the other hand, tensile strength and elongation of PTFE-composites decreased with the increase in fi ller content. Their study found bronze as a promising fi ller material for obtaining higher tensile strength and lower elongation. Wang et al. [6] experimental study revealed that single incorporation of short carbon fi ber and graphite signifi cantly reduces friction in the case of composites based on PI and its wear resistance. Song et al. [7] investigated the effect of addition of glass fi ber and molybdenum disulphide (MoS2) on wear and friction of PTFE-composite with chopped carbon fi ber (20 wt.%) as fi ller. Their study found an increase in friction coeffi cient with the sliding speed and its decrease with the load when used steel ring as counter surface. The addition of MoS2 to PTFE composite increased its scratch resistance and therefore reduced the wear rate. Gujrathi et al. [8] experimental studies also observed reduction in the wear rate due to fi ller materials addition. Their study observed that the development of a protective layer between the pin and counterface assisted in decreasing the wear volume loss. Shen et al. [9] investigated the tribological performance of PTFE fi lled SiO2 particles-epoxy composites. Their study observed that adding 10-15% of PTFE yields in lowest coeffi cient of friction and wear rate under dry sliding with bearing steel balls as counterface. In another study, Shen et al. [10] compared the abrasion resistance of PTFE using Al2O3 particles with sizes in the range 5 to 200 μm. Their study revealed that the abrasive size signifi cantly infl uences the tribological characteristics of tribo-pairs. Sawyer et al. [11] observed the wear resistance of PTFE composite reinforced with 40 nm alumina particles increased with fi ller concentration. Kim et al. [12] study found a decrease in friction coeffi cients with the normal load and sliding velocity. Wear rates observed as decreasing with the rise in normal load. However, initially wear rate increased with the sliding velocity and then decreased. Wang et al. [13] investigated the wear properties of textured stainless steel opposed to polymer surfaces. EDX analysis performed by them showed different wear behavior. Desale and Pawar [14] studied the wear and friction characteristics of solid lubricant PTFE reinforced with carbon, MoS2, glass fi ber, polyether ether ketone particles under dry and wet conditions against SS304 stainless steel. They observed the minimum wear rate for the PTFE composite fi lled with 15% glass fi ber and 5% MoS2 particles.
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