# Selected Properties of Overlaid Magnesium Based Composite Panels for Flooring
## 3 Results and Discussion  
Overall properties of the samples are displayed in Table 1. The highest MOE and MOR values of 4406 MPa and 3478 MPa were found the oak and linoleum overlaid samples loaded on the side of magnesia substrate. Oak overlaid samples had significantly higher bending characteristics as compared to those of linoleum samples due to nature of solid oak veneer. As it is a well-known fact that wood is a natural composite having much higher strength properties as compared to any kind of wood based composites such as particleboard or fiberboard. When strength properties of oak veneer are compared to that of linoleum, soft and pliable properties of linoleum would be responsible for such finding. Similar results were also observed in a preview study carried out panels made using walnut wood veneer as overlay [2, 15]. MOE and MOR values of the samples are also illustrated in Figure 3. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & & & & & & & & & & \\ \cline{5-10}
**PANEL** & **MOE** & **MOE** & **IB** & & & & & & & \\
**TYPE** & **(MPa)** & **(MPa)** & **(MPa)** & & & & & & & **24 h SOAKED** \\ \cline{5-10}  & & & & **2 h** & **24 h** & **R\({}_{\text{a}}\)** & **R\({}_{\text{Z}}\)** & **R\({}_{\text{a}}\)** & **R\({}_{\text{Z}}\)** \\ \hline A1 & 2822 & 21.16 & 1.10 & 0.13 & 0.18 & 8.30 & 56.20 & 9.30 & 70.5 \\  & (190.18) & (1.82) & (0.10) & (0.01) & (0.09) & (0.61) & (2.2) & (1.5) & (3.4) \\ \hline A2 & 4406 & 38.15 & 1.13 & 0.14 & 0.19 & 7.90 & 54.39 & 8.88 & 74.9 \\  & (410.20) & (3.71) & (0.12) & (0.09) & (0.08) & (0.45) & (2.9) & (2.1) & (4.3) \\ \hline B1 & 2716 & 10.54 & 1.06 & 0.11 & 0.12 & & & & & \\  & (230.40) & (1.32) & (0.08) & (0.08) & (0.01) & - & - & - & - \\ \hline B2 & 3478 & 22.29 & 1.08 & 0.10 & 0.13 & & & & & \\  & (310.22) & (2.14) & (0.09) & (0.09) & (0.12) & - & - & - & - \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Test results of the samples. (Numbers in parenthesis are standard deviation values). Application of load during the service life of the flooring panels is not that critical however it was the objective to determine magnitude of brittleness of magnesium substrate within the scope of this work [15; 16; 17]. It appears that both oak veneer and linoleum overlaid samples developed higher resistance resulting in enhanced bending properties of the panels in the case of application of load on substrate direction. When load was applied on overlaid direction, both types of overlays had lower stiffness resulting in lower MOE values consequently also lower bending strength values. Internal bond strength values of the samples ranged from 1.06 MPa to 1.13 MPa revealing no noticeable difference between two types of specimens as can be seen in Figure 4. All samples had failure between magnesium substrate and overlays with exception of several glue failures. Overall findings of IB strength values suggest that the glueline between magnesium substrate and overlays were quite strong and no peeling or separation would be expected during service life of these flooring panels [18]. Figure 4: Internal bond strength values of the samples. Figure 3: Bending characteristics of the samples. Linoleum overlaid samples had very insignificant thickness swelling ranging from 0.10% to 0.13% for 2 h and 24 h water soaking, respectively, as shown in Figure 5 Being hygroscopic material solid wood veneer overlaid samples had higher thickness swelling values of up to 0.19% which is still considered very low. As a result of water soaking test none of the samples showed any deterioration with exception of oak veneered samples had some roughness due to their hygroscopic nature. It appears that such products can be used where there is high humidity fluctuation without having any problems [19; 20]. It can be stated that dimensional stability of the samples is satisfactory. A past study investigated walnut overlaid magnesium substrate flooring panel also determined comparable thickness swelling values of the samples [2].