Our customer had sourced large glass parts from Red China for an outdoor application, expecting them to withstand the test of time. However, within just a few months, a concerning issue arose – the glass became discolored and, in some instances, began to crack. This unexpected deterioration prompted a thorough investigation into the composition of the glass, especially given that a specific borosilicate glass type had been initially specified, one known for its resistance to ultraviolet (UV) radiation.
To delve into the heart of the matter of the glass discoloration, we employed X-ray Photoelectron Spectroscopy (XPS) to quantitatively analyze the elemental composition of both the specified borosilicate glass and the yellowed glass, excluding hydrogen. The results were staggering. The glass supplied from China exhibited a mere one-ninth of the boron concentration present in the specified glass. Furthermore, the Chinese-supplied glass had significantly elevated levels of sodium, measuring three times higher than the specified glass, as well as doubled concentrations of barium. Additionally, unexpected traces of calcium were found in the Chinese glass, a factor absent in the specified composition. Potassium, chlorine, and zinc were also detected in the yellowed glass, elements entirely absent from the clear, specified glass. Moreover, the substituted glass lacked the small concentration of fluorine observed in the specified glass, and its carbon content featured carbon-oxygen bonding, a characteristic not found in the specified composition.
Upon further analysis, it was discovered that the specified borosilicate glass possessed a lower coefficient of thermal expansion (CTE) compared to the substituted glass obtained from China. This discrepancy in CTE proved pivotal, as it explained the occasional cracking observed in the Chinese-supplied glass parts. The mismatch in thermal expansion between the substituted glass and the structural materials that held it in place led to these cracks, highlighting the importance of aligning the glass’s thermal properties with its intended application and surrounding materials.
This detailed analysis not only shed light on the composition disparities but also emphasized the significance of adhering to precise specifications, especially in applications where environmental factors, such as UV exposure and thermal expansion, play a crucial role. Understanding these intricacies is essential for ensuring the longevity and integrity of materials in real-world applications and preventing materials failures such as glass discoloration.
We invite you to reach out to us to address any concerns you may have regarding your glass materials. We are eager to engage in a discussion about your specific challenges, and we are more than willing to explore tailored solutions to help you pinpoint and resolve the issue at hand. Your satisfaction and peace of mind are our top priorities, and we look forward to the opportunity to assist you effectively.
