Student helps assure diamonds stay forever

A WSU graduate student hopes his undergraduate research project results in a few less broken hearts this Valentine’s Day.

In the research project, sponsored by Pounders Jewelers and Hi-Rel Laboratories in Spokane, Colin Merriman worked with David Bahr and Grant Norton, professors in the School of Mechanical and Materials Engineering, to better understand the problem of losing diamonds out of ring settings.

Every year, millions of dollars worth of diamonds or fine gems are lost when they fall out of their gold ring settings because of corrosion at the microscopic level of the material holding them in place. The gold is particularly susceptible to corrosion when it is bent to hold the gemstone.

Merriman studied the corrosion resistance of three types of 18K gold, immersing the materials in a variety of liquids that people commonly use, including a cleaning solution, pool water and hot tub water. He found that, contrary to popular belief, the higher karat gold alloys do corrode, suffering from intergranular failure.

Merriman also found that a new type of white gold, made up of palladium and gold, was far more corrosion-resistant than the traditional nickel white gold and yellow gold alloys.

He has recently published a paper on his work in Gold Bulletin, a trade journal put out by the World Gold Council.