Which of the following statements describes why ion exchange of 99% SiO2 - 1% B2O3 in a salt bath of molten postassium chloride (KCl) is not an effective way to increase the surface strength of the glass sample?
a -The ion exchange works correctly, however both air-cooling and water-quenching are more efficient ways to induce a surface strengthening effect.
b -The glass is composed of only 1% B2O3, which is not a large enough proportion of B2O3 to undergo ion exchange, and therefore does not increase the surface strength of the sample effectively.
c -The potassium ion is smaller than B2O3, so when ion exchange takes place the surface is actually being weakened instead of strengthened.
d =The sample described above is composed of SiO2 and B2O3.
e -Neither of these components are network modifiers, so ion exchange does not take place to strengthen the surface of the glass.
f -The surfaces of the glass sample are not cooled quickly enough to create a high internal strain energy that leads to strong surfaces.
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