ASTM F1147 Test Fixture

Description

ASTM F1147 – Standard Test Method for Tension Testing of Calcium Phosphate and Metallic Coatings

 

ASTM F1147 covers tension testing of calcium phosphate and metallic porous coatings adhering to dense metal substrates at ambient temperatures.

It assesses the degree of adhesion of coatings to substrates, or the internal cohesion of a coating in tension normal to the surface plane.

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ASTM F1147 / Significance and Use

The tensile test method is recommended for tension testing of calcium phosphate/substrate or porous metal coating/ substrate combinations and can provide

information on the adhesive or cohesive strength of coatings under (uniaxial) tensile stress.

The test method may be useful for comparative evaluation of adhesive or cohesive strengths of a variety of types of coatings.

Coatings may be applied using a variety of methods, including, but not limited to, plasma-spraying and sintering.

Information developed using this test method may be useful for certain quality control and design purposes.

The test should not be considered to provide an intrinsic value for utilization directly in making calculations such as determining the ability of a coating to withstand

specified environmental stresses.

Processing variables such as substrate preparation prior to coating, surface texture, coating technique variables or postcoating heat treatment variables may

introduce a significant effect on the results of the tension test.

The specimen being evaluated must be representative of the actual end-use coating.

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ASTM F1147 / Apparatus

Testing Machines—Machines used for testing shall conform to the requirements of Practices ASTM E4.

The loads used in determining tensile strength and yield strength shall be within the loading range of the testing machine as defined in Practices ASTM E4.

See also Test Methods  ASTM E8/E8M.

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ASTM F1147 /Gripping Devices

General—Various types of grips may be used to transmit the load applied to the specimens by the testing machine.

To ensure axial tensile stress, it is important that the specimen axis coincide with the centerline of the heads of the testing machine and that the coating test plane

be perpendicular to the axial load.

Any departure from this requirement (that is, any eccentric loading) will introduce bending stresses that are not included in the usual stress calculation (force/

crosssectional area).

Yoke and Dowel Pin Grips—A schematic diagram of a typical gripping device for specimens with holes drilled for pin loading is illustrated in Fig. 1.

There should be two perpendicular pins in order to maximize off -axis loading

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ASTM F1147 / Summary of Test Method

The tensile test method consists of subjecting a specimen assembly composed of one coated and one uncoated component to a tensile load.

In the case of the calcium phosphate coatings, the components to be tested must be bonded together by use of a polymeric adhesive.

In the case of the metallic coatings, the components may either be bonded with the adhesive, or sintered together.

The adhesive may be in film form or bulk form, but it must have a minimum bulk tensile strength of 34.5 MPa (5000 psi) or as great as the minimum required adhesion

or cohesion strength of the coating, whichever is greater.

The tensile load must be applied normal to the plane of the coating utilizing a tension machine which is capable of determining the maximum strength of the coating

or coating attachment to the substrate interface.

*** Before conducting ASTM F1147 , it is important to read the entire specification. Standards can be obtained from appropriate standard authorities.

 

***PARSROS  offers several types of grips and fixtures which will enable you to perform a variety of tests

  that are accurate and repeatable.