Radioactive Wear
Office of Automotive Engineering

Contact Information

email icon
Contact us:

image: specialized equipment

Specialized equipment and procedures are used when handling radioactive components.

image: schematic of radioactive tracer detector counting and processing radiation from 
					radionuclide tracers

To determine wear data, the SwRI-developed flow-through radioactive tracer detector is coupled to a high-speed multichannel analyzer to count and process radiation from radionuclide tracers.

image: graph showing wear of rings and bearings by time

Radioactive tracer measurements show changes of wear with changes of engine speed and load.

For more than 50 years, radioactive tracer technology (RATT® ) has been used by Southwest Research Institute (SwRI) to make highly accurate and sensitive real-time wear measurements in operating engines and other mechanical systems. Friction and wear are typically measured in engines to evaluate lubricant chemistries, component design and surface coatings. Wear measurements of components can be made using bulk-activated as well as surface-layer-activated methods.

Advantages of Radioactive Tracer Technology

Using sophisticated instrumentation, engineers study real-time wear to instantly detect wear and wear rate changes. Advantages of radioactive tracer measurement techniques include:

  • High sensitivity
  • Cost-effective testing
  • Repeatable measurements
  • Real-time wear data
  • Meaningful results for short tests
  • Easily measured transients
  • Identification of cause and effect relationships
  • Association of wear with
    • Specific design parameters
    • Fuel and lubricant characteristics
    • Engine operating conditions
  • Continuous testing without disassembly for parts inspection
  • Ability to measure wear that is not detectable or measurable by other means

SwRI's radioactive tracer technology can quantify very small changes in wear information in a matter of minutes, whereas conventional test-and-measure procedures can require hundreds of hours to develop a single data point, without the benefits of historical data and trending. Because periodic physical inspection is not required, RATT avoids possible changes in the way materials fit together or in the system's wear state; hence test-to-test continuity is maintained and sequential experiments yield more meaningful results.

Radioactive Tracer Technology Techniques

Three radioactive tracer techniques are typically used to measure internal combustion engine component wear and wear in other mechanical components.

  • Bulk activation (BA)
  • Surface-layer activation or thin-layer activation (SLA/TLA)
  • Nuclear recoil implantation (NRI)

SwRI selects the appropriate method based on specific test objectives, component material composition, and configuration or site particulars. Bulk activation and SLA/TLA are often employed together to increase the number of wear surfaces that can be interrogated simultaneously. For non-metallic parts, or for metal parts that do not produce suitable radioactive tracers during standard irradiation, wear is measured using radioactive atoms implanted into the test piece by NRI. The white paper, Overview of the bulk-activation RATT® method, has more details about bulk activation.

Related Terminology

wear measurement  •  RATT  •  radioactive tracer  •  bulk activation  •  surface layer activation  •  SLA  •  thin layer activation  •  TLA  •  radionuclide tracer  •  RNT  •  real-time wear  •  wear measurement  •  nuclear recoil implantation  •  NRI

Benefiting government, industry and the public through innovative science and technology
Southwest Research Institute® (SwRI®), headquartered in San Antonio, Texas, is a multidisciplinary, independent, nonprofit, applied engineering and physical sciences research and development organization with 9 technical divisions.