Testing Laboratory

During the early 1980's, The APS Materials Testing Laboratory (APSMTL) was born out of the needs of our aerospace coatings division. Since that time, our customer's coating requirements have made the use of a test lab a necessity for every industry we serve.

Our in-house testing capabilities give APS the ability to closely regulate the quality of the coatings we produce and provide for our customers. By monitoring the coating process, we are able to precisely engineer coatings to fill our customer's specific needs. All laboratory testing results are recorded and subjected to statistical analysis, and statistical process control is routinely used to ensure quality in our coated products.

The following specific tests are routinely performed by our test lab.

Tensile Strength
Lap Shear Strength
Shear Fatigue Strength
Macrohardness (Rockwell)
Microhardness (Vickers)
Metallography (Microstructure)
Tabor Abrader (Wear and Abrasion)
Krouse Rotating Beam Fatigue Tensile Test (ASTM C-633-79)*

Tensile Test

Tensile testing provides us with a quantitative measurement of the bond strength of a particular coating to a particular substrate. The type of coating failure during the test can provide important information about the coating-substrate system. Critical applications, such as plasma coatings on biomedical implants and jet engine components, usually require the periodic tensile testing of test specimens to ensure that the process is controlled. Aerospace companies have adopted a process similar to tensile tests known as lap shear strength tests to determine the maximum shear force required to fracture a coating. Our experienced technical staff is capable of providing a detailed analysis of any coating failure.

Shear Strength Test

This is a standard method of measuring the shear strength of coatings for biomedical implants and other applications. The test specimens are similar to those used for tensile strength tests. However, the tensile machine test fixture is designed to apply a shear force parallel to the coating surface. At failure, the maximum shear strength of the coating is determined.

Macrohardness

This test is particularly useful in determining the physical characteristics of brittle materials, such as ceramics. Similar to macrohardness, it is an important indicator of the coating density, wear resistance, and particle-to-particle cohesion.

Metallography

Metallography examines the microstructure of materials in order to evaluate coatings and their substrates. A material's microstructure is a helpful indicator for determining coating quality. In many cases, the evaluation is aided by the use of photo standards of similar microstructures with various types of defects. Coatings are routinely examined for evidence of unmelted particles, metallic inclusion, voids/porosity, spalling, micro-cracking, and embedded contaminants. Metallic coatings can also be examined for oxide content.

Rotating Beam Fatigue Testing

The application of coatings to titanium alloy and other substrates can, if done improperly, result in lowered fatigue strength. The APSMTL performs fatigue testing to measure any changes in fatigue properties after processing by employing a test machine to apply reverse bending loads to straight-shanked specimen bars. Typically, the bars are subjected to a large number of reverse bending load cycles until either a failure or a successful run out of 10 million cycles occurs.

Tabor Abrasion Testing

Abrasion testing provides information concerning the wear resistance, toughness, and overall stability of a material subjected to a light load rubbing or shearing action. It also has been found to provide valuable information about the formation of debris in biomedical coatings. The FDA and others have adopted test methods to evaluate a variety of coatings. The APSMTL can perform this test to determine the quality of a particular coating or material for a customer’s application.