Measuring dewpoint to control the hydrogen to moisture ratio is essential to achieve consistent properties in metal powder sintered parts. If moisture is uncontrolled or measured with poor quality instruments negative impact e.g. on the dimensional stability of the part or its hardness are likely due to carburization or decarburisation occurring.
Sintering may be carried out in a vacuum however it can also be carried out at atmospheric pressure in an inert gas, with added hydrogen. Due to the powdered composition of the raw material, exposure to moisture inside the furnace can cause clumping, resulting in large holes being created in the finished product. Accurate measurement and control of moisture content is necessary to avoid this. For sintering carried out 600°C, maintaining a constant dew point of -60°C is necessary. The gas is sampled at several points in the furnace and it is necessary to have a fast responding moisture measurement method, so action may be taken quickly if moisture levels rise above the allowed maximum values.
Sintering processes use relatively low temperatures (around 600°C) to bond powdered metals. Sintering results in products that are both light and strong, which makes them suitable for a variety of applications from machine parts to shell casings for ammunition. As an example, sintered metal filters are available with many of the Michell moisture sensors. The sintering process creates a strong product, which is still porous. It provides a finer filter than would be possible with gauze or by machining.
Plug and play, expandable GC design with low ppb capability.
Compact analyzing solution for multiple trace gases.
Functionality of two GCs in one plus trace moisture and O2