For thousands of years, wood has been used as a construction material in homes, furniture and flooring. It is particularly prized for flooring due to its combination of natural beauty, durability and restorability.
Hardwood floors are preferred over other materials, such as carpet, as they keep their color for a long time and are easily cleaned and maintained. However, being a natural material, the majority of wood flooring requires protection that is applied in the form of a surface finish. This protects from various kinds of damage such as scuffing and chipping over time. This article will describe how a Nanovea Tribometer was used to measure the wear rate and coefficient of friction (COF) of three wood finishes, in order to gain a better understanding of their comparative performance.
Importance of Comparing Wood Finish Wear and COF
One important factor in how a wood species is chosen for a particular service is the wear resistance. Different species of wood have variations between the individual cellular and fiber structure, which contributes to their different mechanical and tribological behaviors.
These differences are expensive to determine through actual service tests, as they are difficult to duplicate and require long periods of testing time. As a result, it becomes valuable to develop a simple wear test that can provide reproducible, reliable and straight forward results.
Versatile Wear and Friction Tester
Speed Control from 0.01-5000 RPM
Robust with Open Platform
Large Range of Environmental Conditions
This study was designed to showcase the capability of the Nanovea Tribometer in evaluating the tribological properties of wood in a controlled and monitored manner. This was done by simulation and comparison of three types of wood.
The Courtship Grey Oak and Santos Mahogany samples are laminate flooring types. Courtship Grey Oak is a low gloss, textured slate gray color with an EIR finish, whereas Santos Mahogany is a dark burgundy color, prefinished, with a high gloss which allows surface scratches and defects to be more easily hidden.
Antique Birch Hardwood has an aluminum oxide finish, consisting of 7 layers to provide everyday wear and tear protection. Figure 1 shows the evolution of COF during the wear tests of the three wood flooring samples. It can be seen that there is different COF behavior between each of the Antique Birch Hardwood, Courtship Grey Oak, & Santos Mahogany samples.
From the graph it can be seen that the only sample that kept a constant coefficient COF for the entire test was Antique Birch Hardwood. The sharp increase in COF and then gradual decrease observed in the Courtship Grey Oak could be indicative that the sample’s surface roughness largely contributed to its COF behavior. As the wear on the sample increased, the surface roughness dropped and became more homogenous which would explain why the COF decreased: the sample surface became smoother from mechanical wear.
At the beginning of the test there is a smooth gradual increase in the COF for the Santos Mahogany, which then undergoes an abrupt transition to a choppy COF trend. This may indicate that as the laminate coating started to wear, the steel ball (counter material) came into contact with the wood substrate underneath. This substrate could then have worn at a quicker and turbulent manner creating the noisier COF behavior towards the end of the test.
Table 1: Test parameters for COF and wear measurements
||Antique Birch Hardwood, Courtship Grey Oak, & Santos Mahogany
|Normal Force (N)
|Wear ring Radius (mm)
|Duration of Test (minutes)
Sample of Antique Birch, Courtship Grey Oak, and Santos Mahogany (left to right)
Antique Birch Hardwood
Sample of Antique Birch
Figure 2: 3D view of scan taken for Sample Antique Birch Hardwood
Figure 3: Volume of a Hole
Courtship Grey Oak
Sample of Courtship Grey Oak
Figure 4: 3D view of scan taken for Sample Courtship Grey Oak
Figure 5: Volume of a Hole
Figure 6: 3D view of scan taken for Sample Santos Mahogany
Figure 7: Volume of a Hole
A summary of the results of the wear track scans and analysis on all wood flooring samples after the wear tests were performed and can be seen in Table 2, with more detailed information and images for each sample shown in Figures 2-7. If the Wear Rates of all three samples are compared, we can deduce the sample with the least resistance to mechanical wear is the Santos Mahogany.
Table 2: Result Summary of the wear track analysis.
||Volume Lost (μm³)
||Wear Rate x10-5 (mm³/Nm)
|Antique Birch Hardwood
|Courtship Grey Oak
Antique Birch Hardwood and Courtship Grey Oak had very similar wear rates however their wear behavior differed significantly over the course of their tests. There was a more linear trend observed in the Antique Birch Hardwood, while the wear track of the Courtship Grey Oak was shallow and pitted due to the pre-existing surface texture and finish
This study showcased the controlled and monitored manner in which Nanovea’s Tribometer evaluated the coefficient of friction and wear resistance of three types of wood, Antique Birch Hardwood, Courtship Grey Oak, and Santos Mahogany. As Antique Birch Hardwood possessed superior mechanical properties, it showed better wear resistance.
It was also shown that the texture and homogeneity of the wood surface plays a critical role in how the material wears. The gaps or cracks between the wood cell fibers that were part of the surface texture of the Courtship Grey Oak may become the weak spots where the wear initiates and propagates.
This information has been sourced, reviewed and adapted from materials provided by Nanovea.
For more information on this source, please visit Nanovea.