Method and apparatus for supercooling and solidifying substances

US4389904A · kind A · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventors

• Lewis L. Lacy · Diemelstraße, US
• Michael Robinson · Huntsville, US
• Thomas J. Rathz · Huntsville, US
• Lester Katz · Huntsville, US
• Daniel B. Nisen · Huntsville, US

Key dates

• Filing date: Mar 23, 1981
• Grant date: Jun 28, 1983
• Expiry date: Mar 23, 2001

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C30B29/60
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method and apparatus for preparing and studying samples of materials supercooled and solidified in a containerless, low-gravity environment in bulk form is disclosed which includes an enclosure 10 in which a containerless environment is provided in which a sample specimen 52 is positioned. Method contemplates heating the specimen 52 in the containerless environment, dropping the specimen melt through the tube 12 wherein it cools by radiation, and alternately backfilling the tube 12 with an inert gas whereby the specimen melt cools by both radiation and convection during its free fall. During the free fall, the sample is in a containerless, low-gravity environment which will enhance supercooling in the sample and prevent sedimentation and thermal convection influences. The sample will continue to supercool until nucleation occurs which is detected by silicon photovoltaic detectors. The sample will solidify after nucleation and be completely solid before entering the detachable catcher. The amount of supercooling of the specimen can be measured by knowing the cooling ratio and determining the time for nucleation to occur.