Pinchbeck (alloy) Pinchbeck (alloy) Pinchbeck is a form of brass, an alloy of copper and zinc, mixed in proportions so that it closely resembles gold in appearance. It was invented in the 18th century by Christopher Pinchbeck, a London clockmaker. Since gold was only sold in 18-carat quality at that time, the development of pinchbeck allowed ordinary people to buy gold 'effect' jewellery on a budget. The inventor allegedly made pinchbeck jewellery clearly labelled as such. Pinchbeck jewellery was used in places like stagecoaches where there was a risk of theft. Later dishonest jewellers passed pinchbeck off as gold; over the years
Sodium-potassium alloy In this continuous process, a distillation column is fed with potassium chloride and sodium. In the reaction zone, potassium chloride reacts with sodium to form sodium chloride and potassium. The lighter-boiling potassium is enriched in an upper fractionating zone and drawn at the column head while molten sodium chloride is withdrawn from the bottom. Sodium-potassium alloy Sodium-potassium alloy, colloquially called NaK (commonly pronounced ), is an alloy of two alkali metals, sodium (Na, atomic number 11) and potassium (K, atomic number 19), and which is usually liquid at room temperature. Various commercial grades are available. NaK is highly reactive with