Accession Number:

ADA067078

Title:

Microwave Techniques for Nondestructive Evaluation of Ceramics--Phase II

Descriptive Note:

Final rept. 30 Jun 1976-9 Dec 1978

Corporate Author:

SRI INTERNATIONAL MENLO PARK CA

Personal Author(s):

• Bahr, Alfred J.

Report Date:

1979-02-01

Pagination or Media Count:

92.0

Abstract:

The ability of microwave energy to penetrate some kinds of ceramic materials at frequencies of 100 GHz and higher suggests that microwave techniques may be useful for the nondestructive evaluation NDE of such materials. The work described in this report demonstrates the basic feasibility of these techniques for detecting and locating various types of inclusions including voids in seeded plates of Si3N4. Inclusions as small as 0.005 inch in diameter have been detected using frequencies near 100 GHz. Microwave cross- polarized C-scan images of inclusions have been obtained with a resolution of about one wavelength 3 mm. Some of these images exhibit distinguishing features for different types of flaws. Various practical aspects that affect the ultimate utility of microwave NDE for ceramics are also discussed.

Descriptors:

• *MICROWAVE FREQUENCY
• *NONDESTRUCTIVE TESTING
• *SILICON NITRIDES
• CERAMIC MATERIALS
• CLUTTER
• CROSS POLARIZATION
• DEFECTS(MATERIALS)
• DETECTION
• ELECTRONIC SCANNERS
• FEASIBILITY STUDIES
• HOT PRESSING
• IMPURITIES
• INCLUSIONS
• MICROWAVE EQUIPMENT
• MICROWAVE TRANSMISSION
• PLATES
• RESOLUTION
• SILICON CARBIDES
• SPATIAL DISTRIBUTION
• SPECULAR REFLECTION
• VOIDS

Subject Categories:

• Ceramics, Refractories and Glass
• Test Facilities, Equipment and Methods

Distribution Statement:

APPROVED FOR PUBLIC RELEASE