Engineers focus on ceramics sintering technique

Leicester, UK - Researchers at the University of Leicester, led by Prof Jingzhe Pan of the Department of Engineering, focused on the critical sintering step in the manufacture of ceramics. This method eradicates the trial-and-error approach and applies computer modelling techniques to the manufacturing process.

Manufacturing advanced ceramics, even in this era of ‘precision’ techniques, is still very much a trial-and-error process, according to Pan. Ceramics, he explained, are produced from firstly compacting powders into a solid and then firing the powder compacts in a process called sintering. During this, powders are heated to a temperature where they adhere to each other.

At this stage, materials are essentially repacked more closely, such that overall volume decreases or shrinks, while the density increases. Ceramics are intrinsically brittle, making post-production alterations in dimensions very difficult. Failure to accurately estimate the final dimensions of ceramic parts, therefore, lead to a waste of materials, time and money.

The team’s technique helps to minimise errors during the sintering process.

“Predicting change in dimension during sintering is challenging, requiring extensive data on the material in question," Pan said. “Obtaining the required physical data has been difficult and expensive.  “Our method simply uses density measurements of different ceramics during sintering in our computer software that can predict changes in dimensions, even before production begins.

“This method does not depend on the physical properties of any one ceramic material - it simply uses densification data from a small sample of the material and extrapolates the data, such that it can be applied to larger quantities used in manufacturing. It can, thus, be applied to a wide range of ceramics,” he added.

However, several challenges need to be overcome before this method reaches daily application in industry.  For example, the system will need to be converted into a more ‘user-friendly’ format for industrial use. The technique will also have to be demonstrated in a range of industrial products.

Pan, who has been investigating this process for the last 10 years, added that the ceramic industry is aware of the enormous potential of computer and mathematical modelling and of the benefits of shifting emphasis from historical data to a more predictive approach.