Testing Thermal Spray Powder Flow Using a Hall Flow Meter

       Powder fluidity is expressed by the time it takes for a certain amount of powder to flow through a standard funnel with a specified aperture. The usual unit is s/50g. The smaller the value, the better the fluidity of the powder.



The measurement steps of physical quantity fluidity are:



1) Weigh an appropriate amount of sample, accurate to +/-0.1g.



2) Block the small hole at the bottom of the funnel, and pour the weighed sample into the funnel. Note that the powder must fill the entire small hole at the bottom of the funnel.



3) Start timing while opening the small hole of the funnel, and stop timing when the powder in the funnel runs out.



4) Record the time required for all the samples in the funnel to flow out, and repeat it three times, take the arithmetic mean, and the time record is accurate to 0.2s.

5) If the powder does not flow when the orifice is open, tap on the funnel to start the powder flow. If the powder still does not flow out or the powder stops flowing during the measurement, the powder is considered non-flowable or unmeasurable. The device for measuring powder flowability is shown in the figure below.