Research on Influential Factors for Producing Nanoparticle Enhanced Sol-Gel Composites

Abstract

The sol-gel process provides a cheap and simple method for making ceramic materials. The benefits of producing ceramic materials through the sol-gel process are production at significantly lower temperatures than traditional methods and the ability to be produced in intricate 3D shapes. A major problem holding back the sol-gel ceramics is their lack of structural integrity. This research aimed to find the optimal processing conditions to increase the hardness of the ceramic. The impact of HCl pH, Titania particle amount, Dry temperature, Drying time, and mixing time were investigated through an L16 (45) orthogonal design. The data from all 16 experiments showed that the amount of titania particles had the largest effect on hardness. Hardness increased as the titania particle amount increased. The effect on drying time and drying temperature showed a sweet spot around 2 days and 50℃ where the hardness increased without the risk of fracturing the ceramic. If the sol-gel was dried at too high of a temperature and/or for too long, the resulting ceramic would thermally degrade. The pH of the HCl used in the solution was optimal at a pH of 3. The mean hardness values of pH 1 and 2 were not much lower, but the mean hardness was significantly lower at a pH of 4 and was the most inhibiting factor throughout all the experiments. The mix time was shown to have an optimal condition of 3 minutes of mixing before drying. This goes against intuition, however, it can be noted that there existed room for error due to the hand mixing of the sol-gels. The experiments provided a great insight into how the processing conditions of the sol-gel affect the final ceramic. Further experiments are required to decode and optimize the conditions for a structurally stable sol-gel ceramic. The mitigation of human and machine error alongside an investigation into the effect of shape on hardness as well as finding optimal conditions for creating a single large grain will be required to create a sol-gel ceramic that can be applied industrially.