Method for preventing example from being oxygenized by double silica tube

Abstract

The present invention provides a method which adopts double quartz tubes to prevent the sample from being oxidated, which relates to the method which can prevent the sample from being oxidated. The method comprises the steps as follows: (1) the sample is placed in a small diameter quartz tube with one end sealed; the other end is neck-sheared by flame and is connected with a rotary sheet vacuum pump; after 30 to 40 minutes of vacuum pumping, the shear neck is sealed quickly by flame. (2) The sealed small quartz tube is placed in a big diameter quartz tube with one end sealed; the other end istreated by neck-shearing by flame, so a double layer of quartz tubes is formed. (3) The neck sheared big diameter quartz tube is connected with the rotary sheet vacuum pump; the vacuum pump is started; after 5 to 8 seconds of vacuum pumping, the sheared neck is sealed quickly by flame. Compared with the traditional high temperature heating oxidation preventing method, the present invention is of simple and easy experiment operation, lower experiment expense, lower experiment risk and higher experiment efficiency.

Description

technical field [0001] The invention relates to a method for preventing oxidation of samples, in particular to a method for preventing oxidation reaction of samples during heating by using double quartz tubes. Background technique [0002] When heating the sample at high temperature, in order to prevent the sample from being oxidized, the commonly used protection methods include gas protection method and vacuum protection method. The gas protection method is to use hydrogen or inert gas to isolate the sample from the air to prevent the sample from being oxidized, and the vacuum protection method is to heat the sample in a vacuum furnace to prevent the sample from being oxidized. The above two methods can both play the role of high temperature oxidation prevention. However, these two methods have shortcomings in application. If hydrogen is used for protection, there is a danger of explosion if it leaks; if inert gas is used for protection, the price is relatively high. The ...

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Problems solved by technology

The effective vacuum requirement for this method is 10 -2 pa, while the outside standard atmospheric pressure is 1.01×10 5 pa, the pressure difference between the inside and outside of the quartz tube is 10 7 Pa, because the wall of the quartz tube will become soft after being heated at high temperature (above 1000°C), and will leak under a large negative pressure, failing to achieve the purpose of anti-oxidation

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