Whipping up a metallic frappe.

Using only a kitchen blender and a laser, researchers have come up with a faster cheaper and cleaner method of producing ultrafine metal powders, such as the silver used in making solder dental fillings, and high-speed photographic film. They can produce either individual particles or clumps of particles, such as the clusters of 10-nanometer particles of nickel and nickel oxide shown here.

Jogender Singh, a materials scientist at Pennsylvania State University's Applied Research Laboratory in State College, developed the process to produce silver and nickel powders. By firing a laser into a whirling solution of inexpensive chemicals, Singh and his team create hot spots where the materials react to form tiny particles of metal, they report in an upcoming issue of the Journal of Materials Science.

The researchers can control the size and to some extent the shape of the particles by varying the concentrations of the chemicals in the blender, the intensity of the laser, and the blender's speed

The technique can create particles of silver metal ranging in size from 1 to 100 nanometers--smaller than the smallest bacteria--at rates of up to 3 grams per minute, Singh says. This yield exceeds that from any other technique except grinding, which cannot generate such small particles. The silver powder is also purer and more uniform, he adds.

Production of increasingly fine metal powders "is a growing area of interest," says Steve Lampman of ASM International, an engineering materials society in Materials Park, Ohio. "Everybody wants to get powder size down for a variety of reasons--better mixing better reactivity, and lower processing temperatures.