DiaPac - Determination of Physical Data

Determination of Physical Data

for average particle size:

measures the air resistance offered by the powder under test (the air resistance is inversely proportional to the average size of the powder’s particles, normally expressed in microns)
average particle size knowledge is an important guide to the properties of the matrix in manufacture and service

for specific gravity (theoretical):

determined from the actual specific gravities of the components within each matrix powder (actual values will often be slightly less)

for apparent density:

we determine this weight by using an apparatus that controls the flow rate of powder into a container
apparent density knowledge will specify the powder weight to fill a mold (thus affecting mold design and manufacturing technique)

for hardness:

determined by using a Rockwell hardness testing machine (values quoted are on Rockwell C scale)

for relative strength:

determined by measuring the minimum force (in kgs.) required to fracture the standard coin specimen (a 2.7-cm-diameter steel ball bearing, a 3.02-cm-I.D. steel ring, and a hydraulic bench press are used)

for percentage infiltration:

the ratio of the bond metal weight to the finished standard coin’s total weight (expressed as a percentage)

for control screen mesh (99%):

we carefully control each powder’s mesh size to ensure uniformity (our technical data pages in this catalog show the size through which 99 percent of the powder will pass)

for manufacture of the standard coin:

to determine hardness and relative strength properties, a “coin” is prepared using techniques appropriate to the matrix (for example, infiltration, hot-press, sinter)

infiltration test coin specifications