Market Requirements

There are many everyday examples of complex metal and metal/composite structures that must maintain structural integrity throughout their useful life, despite significant wear and tear as well as accidental or intentional damage. These structures include aircraft skins, ship hulls, highway structures, pipelines of all kinds, in ground fuel tanks, off shore drilling platforms, semiconductor manufacturing equipment, etc. The list is virtually unlimited.

Corrosion is a major factor in reducing the structural integrity in the life of these structures. Paint is used in many structures to protect the surface of these structures. Due to many reasons, moisture may penetrate between the paint and the metal, causing hidden corrosion. This type of corrosion is difficult to detect and correct. In many structures, metal failure, or extensive and expensive maintenance are the traditional methods to determine elements of the structure where corrosion may have occurred. The Analatom Corrosion sensor technology provides a cost effective way to determine whether critical hidden (e.g. painted) parts of a structure may be suffering from corrosion.

Today, the traditional method of repairing these structures requires drilling and riveting of plates over damaged areas. This method introduces inherent reliability problems, usually associated with increased stress and danger of corrosion at the rivet holes. A newer more reliable method is to adhesively bond plates over the damaged areas or to bond other structures together to form a new solid integral structure. This methodology has had one major flaw to-date, namely a cost effective and reliable technique for the through-life non-destructive evaluation (NDE) of adhesively bonded structures for potential failures like bond separation and corrosion of the structure. The adoption of the Analatom in bond sensor would be expected to redress this problem and lead to increased use of adhesive bonding and thus a larger market.

Key NDE market drivers for the aerospace industry are high replacement costs which will keep aging equipment in operation and for the aging highway infrastructure the industry is looking for cost effective means of meeting regulatory safety requirements.

Analatom's solution to the detection of corrosion in hidden metal and metal/composite structures is to develop a "smart material" consisting of a number of micro-scale (MEMS), independent, wireless sensors that can be mounted underneath the metal coating or within the adhesive bond-line. These sensors will fulfil a major corrosion sensing need, namely the need for a nondestructive test for corrosion detection or for partial bond degradation detection without requiring the removal of protective coating on the structure or disbonding of parts of the structure.

The MEMS "smart material" concept must be achieved with minimal impact on the structure. This immediately rules out systems with a multitude of wires connected to each individual sensor. Also, the coating and adhesive bond line can be as thin as 80µm, determined by the thickness of an internal support/spacer scrim. As a consequence the sensors must be largely autonomous and fabricated to be less than 80µm thick. This implies internal control circuitry, preferably CMOS for low power requirements, fabricated on wafers that can be back thinned to produce less than 80µm thick devices. Under a SBIR U.S. Air Force contract Analatom has prototyped and tested such devices.