Coefficient of friction measurement

Fig. 23 Contact fatigue behaviour of methylmethacrylate random copolymers under fretting conditions. White circle Glutarimide co-monomer (76%), black circle cyclohexyl malemimide co-monomer (25%). The maximum value of the tensile stress has been calculated at the edge of the contact, where cracks initiate, and for values of the coefficient of friction measured at crack initiation...

The upper phase had high viscosity. When this phase was used for lubrication studies it gave low coefficient of friction. A strong correlation between coefficient of friction measurements and wear-scar diameter was seen and was observed previously. 

Figure 2.18 Coefficient of friction measured as a function of temperature for (a) C/C and (b) C/BN.

SRR varies from 0 to 200% with SRR = 0% ( bau = disk) representing pine rolling and SRR = 200% for complete sUding conditions. A SRR of 10% was used for all experiments to maintain the conditions of near-pure rofling. Using the manufacturer s software (PCS Instmments, MTM version 1.0, London, UK) the speed can be varied from 0 to2500 mm/ s. A load of 10 N was appUed (Hertzian contact pressur-e = 0.42 GPa) and the coefficient of friction measured as a function of the mean speed of the disk and the ball. A temperature of 25 °C was maintained by means of a water bath. New disks and balls were used for every measurement. 

Coefficient of friction measurements have been reported for nitrile rubber [96]. 

Miyata and Yamaoka [152] used scanning probe microscopy to determine the microscale friction force of silicone-treated polymer film surfaces. Polyurethane acrylates cured by an electron beam were used as polymer films. The microscale friction obtained by scanning probe microscopy was compared with macroscale data, such as surface free energy as determined by the Owens-Wendt method and the macroscale friction coefficient determined by the ASTM method. These comparisons showed a good linear relationship between the surface free energy and friction force, which was insensitive to the nature of polymer specimens or to silicone treatment methods. Good linearity was also observed between the macroscale and microscale friction force. It was concluded that scanning probe microscopy could be a powerful tool in this field of polymer science. Evrard et al. [153] reported coefficient of friction measurements for nitrile rubber. Frictional properties of polyacetals, polyesters, polyacrylics [63], reinforced and unreinforced polyamides, and polyethylene terephthalate [52] have also been studied. 

Tables 8.1 and 8.2 summarize, respectively, the coefficient of friction measurements from AFM for different trichlorosilane SAMs and the corresponding dichroic ratios obtained from NEXAFS measurements. In both tables, the given values are compared with those for uncoated (bare) silicon. A remarkable correlation is seen in the trends for the order in the dichroic ratio and the coefficient of friction. SAMs with higher dichroic ratios have lower coefficients of friction. Combining the measurements from NEXAFS and FTIR with the AFM measnr ents of friction coefficient, the C12 film emerges as the most ordered systan with the lowest friction. This conclusion is also supported by molecular dynamics simulations [37]. Mikulski and...

Coefficient of Friction Measure of the resistance to sliding of one surface in contact with another surface. See Friction. 

Coefficient of friction measurement TMI slip and friction tester The peak angle (static) and average force (kinetic) are measured. An emulsion polymer with low glass transition temperature is required for high sHde angles. 

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