What should be paid attention to when selecting a vacuum sintering furnace?
1. Temperature
For heat treatment processes, the primary issue is temperature. Vacuum sintering furnaces heated by resistance wires are limited by high temperatures. There are three different insulation materials here: ceramic fiber insulation materials, and metals (molybdenum or tungsten) Anti radiation barrier and graphite felt. Iron chromium aluminum and silicon molybdenum rods are two common heating elements. Ceramic fibers with low thermal conductivity are used to isolate heat. These two types of heating elements need to be heated in an oxygen atmosphere to form an oxide protective layer on their surface. The insulation material of heating elements made of molybdenum or tungsten is a radiation resistant sheet made of its own material. These radiation shields are composed of multiple layers, used to reflect thermal radiation and provide insulation. This type of heating element and insulation material is prohibited from containing an oxidizing atmosphere. Due to the low vapor pressure of metal materials, high vacuum can be achieved. The insulation material for graphite heating elements is graphite felt, and it is prohibited to contain an oxidizing atmosphere. Due to the influence of graphite vapor pressure, carbon elements are inevitably released into the vacuum sintering furnace during the heating process. Different heating methods have different temperatures. The range is from 30 to 1300 degrees Celsius, and the second range is from 1300 to 3000 degrees Celsius
2. Atmosphere
The next question is to determine which atmosphere the heat treatment process is to be carried out in.
. Temperature ranges under different atmospheres and different heating elements. It is important to match the heating elements with different atmospheres. Even carbon monoxide, helium, and ammonia can be introduced. According to the following rules: at a temperature of 1800 degrees Celsius, it can be air or atmosphere, such as air, oxygen, nitrogen, argon, hydrogen, and various vacuum levels. If the working temperature is between 1800-2200 degrees Celsius, the heat treatment process should be carried out under nitrogen, argon, hydrogen, and various vacuum levels. If a high-temperature furnace with a temperature between 2200 and 3000 degrees Celsius is required, the process must be carried out in an argon atmosphere At this point, the temperature and atmosphere conditions of the vacuum sintering furnace heat treatment process have been clearly introduced. The relationship between heating elements, temperature, and atmosphere can be referred to, and these rules can be applied to different furnaces. In addition, the selection of furnace is also related to effective space, loading, etc
