Metal Finishing Laboratory Testing

Coating Thickness

Coating thickness is an important variable that plays a role in product quality, process control, and cost control. By recording and monitoring the thickness of the coating, we can keep a tab to avoid over and under application. This helps in keeping the surface finish right while maintaining the performance as well. The test is often performed on parts that go through Cadium Plating and Anodizing. This is a destructive test.

Coating Weight

Coating weight is determined on a test panel or part with a known surface area is first weighed as-is. This test is performed to measure the coating weight on the part in comparison to specifications requirements. Coating weight is typically performed on Anodize, Chemfilm, and Phosphates. This test is destructive to the coating.

Copper Sulfate Testing

The copper sulfate test in intended to test the surface passivity of corrosion-resistant steel parts. The test determines the presence of free iron which is often transferred onto the surface of a part during fabrication with steel components.

Cross Hatch

The Cross Hatch Test Method is widely used to assess the adhesion of paint coatings and provides an instant assessment of the quality of the bond to the substrate.  The cross hatch test is a visual comparison method for paint and powder coatings up to a specified thickness. This is a destructive test of the coating, so it is typically performed on a representative panel.

Dry Tape Adhesion

The tape adhesion test method uses pressure-sensitive tape to determine the adhesion quality of a coating. In order for coatings to perform properly, they must adhere to the surface on which they are applied, and the tape adhesion test can determine whether or not a coating is properly adhering to it’s substrate. This test should be non-destructive if coating has bonded successfully.

Dye Spot (Anodize Seal)

This test can verify the integrity of an anodize seal but shall not be performed on dichromate seals.  An acid solution may be used to prepare the surface and dyes are applied to see if the coating resists the dye or absorbs it.  This is a potentially destructive test and is typically performed on a representative panel.

Electrical Resistance (Chem Film)

Electrical Resistance is performed in accordance with MIL-DTL-81706.  This test is designed to ensure that chemical conversion coatings do not exceed electrical resistivity requirements of the conversion coating.

Ferroxyl (Passivation)

Ferroxyl test is used on stainless steel to detect iron contamination, including iron-tool marks, residual-iron salts from pickling solutions, iron dust, iron deposits in welds, embedded iron or iron oxide.

Humidity Testing

Humidity testing is an environmental test to identify any anodic surface contaminant of corrosion resistant steel including free iron. This test is performed for post-passivation verification.

Salt Fog Testing

Salt fog is a type of accelerated corrosion test that is performed to assess the comparative corrosion resistance of certain materials when exposed to salt fog or salt spray at increased temperature levels. In this test, specimens are put inside a chamber or cabinet for salt fog testing, with constant salt water spray or indirect fog, while the climate is maintained during the test. This is used for periodic testing to ensure anodize, chemfilm, cadmium plating, and other coatings meet requirements.

Oxalic Acid Spot (Black Oxide)

This test is designed to evaluate the integrity of the black oxide coating.  An acid solution is placed on a finished part or panel, rinsed clean and evaluated to see if there is any attack to the coating.  It is an acceptance test which is destructive.

Taber Abrasion (Hard coat)

Taber abrasion is a method used to determine the ability of a material to withstand wear. Taber abrasion is evaluated using what is known as a Taber abrasion test or Tabor abrader. Taber abrasion uses two abrasive wheels that the material being evaluated is rotated underneath for a given time and under a given load. This is primarily to ensure the hard coat anodize can stand up to the wear resistance that parts with this coating will undergo. This is a destructive test.

Wet Tape Adhesion

Wet adhesion refers to the physical property of a coating whereby it has the ability to strongly affix to a substrate material in the presence of moist environmental conditions such as rain. Wet adhesion is particularly important when protecting exposed metal surfaces against corrosion because they are exposed to the atmosphere and therefore are prone to moisture contact and electrochemical reactions. This is a destructive test.