Tribological Laboratory


United Protective Technologies operates a macro, micro, and nano scale tribological testing laboratory. Wear, abrasion, and coating adhesion tests are carried out at UPT. Testing performed at UPT conforms to ASTM, DIN, and MIL spec standards.

WEAR

In materials science, wear is the erosion of material from a solid surface by the action of another surface. It is related to surface interactions and more specifically the removal of material from a surface as a result of mechanical action.

UPT operates a high-tech surface failure analysis laboratory that performs wear, friction, adhesion, and other tests on coated parts.

Wear Test Methods: Tribometer

A Tribometer is used for testing a surface for friction and/or wear. UPT uses a pin on disk type Tribometer that consists of a stationary "pin" under an applied load in contact with a rotating disc. The pin can have any shape to simulate a specific contact, but spherical tips are often used to simplify the contact geometry. The friction coefficient is determined by measuring the deflection of the elastic arm that holds the pin. The wear coefficient is calculated from the volume of the material lost during the test.

(ASTM – G99, G133, G77 DIN – 50324, 51834)

tribometermicro scratch track

Figure 1: Tribometer test stand (left) w/magnified wear track (right).

ADHESION

One of the primary requirements of any coating is excellent adhesion of the coating to the substrate, a property that can be defined as the interfacial forces between two surfaces.

Scratch Test Methods: Revetest

The scratch tester moves a Rockwell diamond tip with a radius of 200µm across the coated surface of a substrate at a constant velocity while an increasing normal force is applied with a constant loading rate. The scratch test introduces stresses to the interface between coating and substrate causing delamination or chipping of the coating. The critical normal force at which the first failure of the coating is detected is termed the critical load. UPT uses a CSM Revtester for this type of testing.

(ASTM – C1624, D7187, D7027-05 DIN –7071)

test

Figure 2: Progressive scratch captured with Revetest.

Coating Thickness Test Methods: Ball Crater

A rotating steel sphere of known diameter is pressed onto the surface of a coated test piece or component. When slurry (diamond or silica) is applied to the contact area a crater is abraded through the coating to the substrate. Wear diameters on the coated surface are measured with an optical microscope and the coating thickness is calculated.

ABRASION

Abrasion is the process of scuffing, scratching, wearing down, marring, or rubbing away. It can be intentionally imposed in a controlled process using an abrasive. Abrasion can be an undesirable effect of exposure to normal use or exposure to the elements.

Abrasion Test Methods: Severe Abrasion Test

The severe abrasion test is performed by rubbing the coated surface with a hand held, spring loaded hardness tester that has been calibrated to 2.5lbs of force. The calibrated hardness tester utilizes a MIL SPEC certified pumice eraser to abrade the surface during the testing process. Subsequent to the testing process the sample cleaned, dried and visually examined. The coating passes if there is no visible abrasion and no coating has been removed.

(MIL-F -48616, MIL-C-48497A or MIL-C675C)

Falling Sand Abrasion Test

Optical coatings and substrates erode under severe environmental conditions. Even sand at very low velocities will severely degrade optical coatings and sensors over time. UPT has adopted a sand drop test that will quickly and efficiently compare optical coatings and substrates in a sand environment. The test can be tailored to be more or less aggressive based on the media that is used in the test.

(ASTM – D968-05)

OTHER AVAILABLE SERVICES

  • Contact Profilometry
  • Raman Profilometry
  • Optical Microscopy
  • Indentation Hardness Test
  • VDI 3198 Adhesion Test
  • Accelerated Aging ASTM D4329, ASTM D4597
  • Extreme Velocity Impact Analysis Chamber (EVIAC)
  • Rain Erosion
  • Sand Erosion
  • Large Particle Impact

TECHNICAL POINT OF CONTACT

Jeffery Neurauter (Engineer / Account Executive)
704 888 2470 x.30
jneurauter@unitedprotec.com