Alloy are relatively similar in size, the atom exchange method usually happens, where some of the atoms composing the metallic crystals are substituted with atoms of the other constituent. This is called a "substitutional alloy". Examples of substitutional alloys include bronze and brass, in which some of the copper atoms are substituted with either tin or zinc atoms respectively. In the case of the interstitial mechanism, one atom is usually much smaller than the other and can not successfully substitute for the other type of atom in the crystals of the base metal. Instead, the smaller atoms become trapped in the
Sundown Tin and Copper Mine Sundown Tin and Copper Mine Sundown Tin and Copper Mine is a heritage-listed mine at Little Sundown Creek, Stanthorpe, Southern Downs Region, Queensland, Australia. It was built from to 1920s. It was added to the Queensland Heritage Register on 28 July 2000. Tin was discovered at Sundown in 1893, and a reward claim was granted for 40 acres, but at that date there was no machinery on the ground. Mining had ceased in 1894 for want of equipment, and copper prices were at rock-bottom at that time. The copper and tin deposits were on opposite sides of Little Sundown Creek,